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Peter Haydon's Anima

Page history last edited by Peter Haydon 3 years, 8 months ago

Sailing on Swan Bay, Victoria, Australia (2015)

 

I currently keep Anima on flat water, where I've done most of my sailing the last three years, after my ocean drowning attempt (see below). I keep it on Swan Bay at Queenscliff-Lonsdale Yacht Club, the nicest, friendliest (and cheapest) club I've ever been a member of. They tolerate and even encourage my eccentricities. It's like travelling back to the 50s - you drive down a dirt track, cross a train line which is used daily by a steam train, and end up at a club house which looks like a Country Women's Association hall c.1955.

 

Swan Bay is a beautiful, very enclosed bay about 4km by 10 km. It's almost a salt water lagoon,  with only two narrow channels to Port Phillip Bay. Average depth is about 60cm at low tide, not much more at high tide. It's a gorgeous national park - in the still clear water you can glide over banjo sharks, gummy sharks and stingrays - it's like snorkelling and sailing at the same time.

 

 

 

Anima works quite well in the thin water.

 

But I have mods in mind:

  • Remove one hull and go single-outrigger - this is a config rather than  a mod, I can do it in about 30 minutes, but I've yet to try it. Saves about 5 kg. I'll use an inflatable beach roller as a safety ama.
  • Clean up the messy deck layout - in particular: cleat halyards and downhauls at masts rather than leading them to helm, and running them to deck level rather than the dashboard I currently have; simplify leeboard raise/lower; rudder mods (see below).
  • Cut off the box/seat currently glued to the centre cockpit lid.
  • Remove hinges from hardshell cockpit covers and just make them bungee tie-down (like my Windrider 17). This makes them easy to remove completely on light days (I'd still keep the inner waterproof neoprene hatch cover on the bow hatch) and saves a little weight.
  • Build a NACA 0012 section quarter cassette rudder and remove foot pedal steering option. This simplifies the deck a LOT, and should be larger, lighter and more hydrodynamic than my current aluminium plate rudder
  • Build a new wider & deeper NACA 0008 section leeboard.
  • Make an optional very light camping deck that fully decks the ladders.

 

 

You can see the ladders used for side-benches. The box I'm going to remove is in front of my feet.

 

 

Despite its low freeboard I find this fairly dry boat for the sailor (even in nasty 1 metre chop - It pounded but I wasn't that wet.) I think it's because it is not super-fast (gets up to about 12kmph in 20 kmph of wind) and perhaps also because I'm sitting quite high and far back from the bow. Ideally heavy stuff is stowed forward of the helm position.

 

And some pretty reflections...

Anima takes a couple of people plus modest gear quite comfortably - it's based on an enormous 6.5m high-volume tandem kayak.

 

I haven't given up on the idea of ocean coastal cruising in this boat, but I've been preoccupied with the Windrider 17, a much "bigger" boat (even though it's shorter). The Windrider 17 is going to Tasmania soon, and I'll pay more attention to Anima then and do some more cautious ocean testing.

 

Almost ready (2013)

 

Over the last year and half I have made a number of changes to Anima, many expressly designed to make the vaka more ocean-worthy:

 

  • rear hatch is now permanently sealed at the deck.
  • front hatch/maststep is to be permanently sealed.
  • front and rear mast positions now have sealed mast tubes ie water can't get into the boat via mast positions.
  • Rear mast has been moved back about 30 cm so it is at the rear aka, and a new mast partner made to suit. This clears the deck a LOT.
  • front and rear bulkheads now have hatches. There is also a little rudder access hatch at the end of the deck.
  • whitewater flotation bags (two for each compartment) for bow and stern compartments
  • front and rear hatches now have neoprene covers AND hardshell covers.
  • All deck holes (from unused fittings etc) are filled except a centre deck hole which can be used for a third, short-canvas mast position (this would be good for serious expeditions but is optional really). Alternatively I can use the hole to mount a hand-pump.
  • A new much stronger design steering box with adjustable steering line tension has been made for the rear mast position. The old one didn't fail but it did crack.
  • A slight crack in the hull (from falling on the trailer during a windstorm at home) is fixed such that it is now stronger than the rest of the hull
  • The trailer now has customised long padded runners to reduce the risk of hull cracks.
  • The rear hatch cover now has a box on it which can be used as a seat for paddling. Front steering pedals for use while paddling have been made but not yet rigged.
  • The starboard side side-deck is now moveable and can be pushed out of the way to provide paddling space.

 

I estimate another 20 hrs of touch-up work to make the boat sailable, less if I don't worry about the forward steering pedals - these may not be strictly necessary. It's mostly rigging and re-rigging and some painting to do at this stage.

 

Sinking, not sailing - April 14th 2011

Sometimes I need to do stuff to get whacked in the face by underlying
design problems.

I would like to say I pondered this as Anima
slowly sank off Bell's Beach, but actually I was scared witless and
desperately trying to find my damn handpump.

Executive summary of what follows:

I have a basic design problem which I found out the hard way - not
enough freeboard for my current hatch setup to keep water out in some
conditions.

The long version:

I was setting off on a 3-day coastal-camping ocean trip, my first sail
of more than a couple of hours. It was about 10-15 kts wind, sloppy
short wind waves, quite confused, around a metre high.

 

I packed in a *real* hurry - very stressed, over-tired - I felt this might be the

last decent day of sailing for the year - only my fourth sail of the summer/autumn.


It went really well for the first leg from Anglesea to Point Addis,
though the boat sat very low in the water with all the camping gear and
20 litres of fresh water. To lay my course it was mostly upwind, as high
as I could point. For the first timke I had a GPS working (I love that
thing) so I could see I was going upwind at about 5 -6 kmph and reaching
at about 10-12 km/ph - hardly stellar performance but it seemed quick
enough to me, and a modest tide was against me.

But as I was passing Bell's Beach (of world surfing fame) I noticed
that the boat was definitely sitting lower in the water. No need to
panic, I thought, I'll just sheet in the mizzen, ease the foresail and
let the boat hold itself to wind while I check inside the hatch. Then
things started to go to pieces rapidly.

(To understand the next bit:
There is a fore hatch to the fore sealed compartment which I didn't
touch, two cockpit hatches I made to cover the original fore and aft
cockpits of the kayak-based vaka, and an original large square rear hatch  - annoyingly hard to seal,

and missing its inner liner - to the rear "sealed" compartment.)

Sure enough there was water in the hull - at least 60% full in the main
central compartment. I started to panic and looked for the handpump
which I had packed somewhere inside the hull - but which hatch? I opened
the front cockpit hatch, couldn't find it. Opened the rear cockpit
hatch. Immediately water started washing in from the sea and my drybags
started popping out. Really panicked now, I opened the rear hatch (which
I swore never to do at sea. Now the rear compartment, also more
than half-full, filled completely in seconds. I was an idiot and I was going to
die, or have to set off the EPIRB - not sure which was the worse prospect.

Then the rear hatch over floated away. Did I mention I had already lost
a hatch cover in a previous trip? Had not yet provided a tie for it...Slow learner.

By now the rear half of the deck was completely awash. I had finally
found the pump, forced most of my drybags back in the hull for whatever
floatation they might offer, then started pumping - a waste of time
because even with the mid-hatch partly on, more water was getting in
than I could possibly pump out. Meanwhile I was drifting steadily in the
onshore wind towards the cliffs at the south end of Bell's.

After a short time I gave up on the pumping, realised I didn't seem to
be sinking any further and decided to see if the boat would still sail - I

needed to get out of there
With most of the boat submerged, both amas deep in the water and the
rear two thirds of the deck constantly awash, amazingly it still sailed...quite fast
cracking up to about 8 km/ph on the reach. My sails were probably moving
at least half a ton total boat weight through the water at this point. Even
so the boat felt relatively easy to sail except when draggy deck
infrastructure like aka mounts (usually well above water level) slammed
into waves. I sailed back to Anglesea, freezing (because I dared not
search for my spray jacket) and made it to the boat ramp at sunset.
I wrapped myself in the space blanket I had on me, and called friends

to come and help me bail the boat to the point
where I could get it out of the light surf, de-rig and trailer home.

Lessons:
1) A fundamental design problem with my craft which should have been
obvious but needed a longer sail, a full cruising load and nasty chop to
really bring home  - my vaka just doesn't have enough freeboard for rough
water, and I fear that my very large cockpit hatches and large rear
hatch will NEVER seal well enough to keep out the water that sluices
over the deck.
2) Have key safety gear, pump etc where I can get at it WITHOUT opening
a hatch. Spray jackets and drinking water count as safety gear. But
ultimately this would not have got me out of the situation caused by 1).
I was underprepared and rushing for a very small circumstantial window
of opportunity to launch for this 3 day trip - and I knew it and should
have simply cancelled - no excuse.
3) My boat, despite its design flaws, has a serious amount of
redundancy. I know now that even with all three compartments flooded

it would not sink so long as the amas are attached, and that it can sail quite nicely
underwater.

Some possible solutions:
1) Replace the vaka. It is a bit on the heavy side, and being a sea
kayak with a sloping deck, can never have much freeboard and will always
invite water over the deck, especially driven at sailing speed through
chop with the extra weight of amas, akas and sail rig. (This would,
however, be a heart-breaking lot of work and expense.) Not until I have

the space to build a 24 ft hull - could be years.
2) Add freeboard by remodelling the deck of the kayak, at least the bits
encompassing the cockpit hatches. This would be complex and add weight,
but might provide some other advantages. Replace the rear hatch
with one or even two 8" screw-in type hatches to access the long rear
compartment (I have plenty of other spots to put big things) so only
the cockpit section of the boat would be enclosed with extra freeboard.)
3) Use the sea kayaker neoprene spray skirts I have on the cockpit
hatches, with something inside them (not me) to hold them up.

 

After thought and consultation, I am doing the following:

 

1) Permanently sealing the rear compartment to the outside, and putting a screw hatch on the vertical inner bulkhead instead (access from rear cockpit, not while sailing). I am also putting a little screw-n hatch right near the end as a maintenance hatch for the rudder bolts. After sealing, I will put in two whitewater long buoyancy bags and inflate , so that even if the compartment floods it will still have a large proportion of flotation.

2) Permanently seal the front hatch - again putting a screw hatch on the inner bulkhead, flotation bags - pretty similar to the rear compartment.

3) Mast alterations: I have a schooner rig with identical sails fore and aft. To simplify support structures I'm moving the aft mast back about 40 cm- if this causes too much weather helm I can (in the short term) reef the rear sail and in the long term ponder other solutions to bring the COE forward or the CLR back - change leeboard position, larger foresail, larger rudder... Both masts now bury into the fore and aft compartments. Instead of the dubious seals I had, I will used bonded-in sealed mast tubes for both masts. I'll probably put in a third central mast position to set a single reefed sail in really heavy weather

4) Add a deck pump: I have a hand pump permanently installed through the deck so I can pump out without opening the cockpit.

 

A few other things like strengthening and altering the tiller design.

 

 

 

 

 

A nice afternoon sail - Jan 26th 2011

 

 

My most pleasant sail to date and the only one with a companion. A beautiful day off Anglesea (Victoria Australia) in light winds and a swell around 1 metre or less. Everything worked, nothing broke. My new sheet bags finally solved the problem of sheets falling off the sloping deck.

 

First sail with a twin mast:

 

 

Here's some video which givess a good idea of the layout of the hull and the speed of the boat through the water (sorry, no GPS on this trip).

http://www.youtube.com/watch?v=bnUShJcVoQM

 

Dec 5th - launch

 

 

This was the launch after five years of messing around. Apart from breaking a tiller extension, most of the untried systems worked. It sailed slowly, I needed a good paddle position and it was very heavy.

So I did some adaptation immediately after - added a sail/mast, reduced the size of the deck boards and the supporting structure and created a paddle position.
After a second sail in somewhat heavier conditions with two sails I was happier with the speed, but the tiller position was a pain so I created some indirect tiller control via lines (ie the tiller is not directly attached to the rudder). This is a little sloppy but is still a great improvement. I also lost my hatch (and miraculously found it again) so resolved to tie it into the boat.

November 21st 2010 - First water - no sails

 

 

I launched Anima for the first time today. It went well, although the amas ride too low in the water - I need to raise the mounts by 2" via an addition to the top of each mount. (Yes that is a spirit level on a ladder - I was trying to find fore-and-aft vertical for various load placements.

 

The picture above show an unbalanced load with my considerable weight behind the aft cockpit, hence the skying bow. For cruising weight will be further forward, sitting at the front on side decks not yet fitted (the ladder is the framework for one of these decks). There may also be a paddling position just in front of the front ama over the rear of the front cockpit - I'll play around.

 

The photo above shows how the outriggers work. In the foreground you can see the hose clamp that holds the elbow of the aka onto an AL cylinder set into the ama - the cylinder is split so the clamp crushes it onto the elbow. There is a second hose clamp visible holding the outer aka to a telescoping inner aka (the rig is currently in "narrow" mode). The outer aka is held onto the mounts with SS/poly ratchet straps.

Both the elbow and the inner aka are built up slightly next to the clamps so they can't easily slip.

 

How this page is organised

 

For information about the main build of the boat, progress from top to bottom. Latest progress and information is at the top of the page.

 

There's a fair bit of text, so skim the headings to find the interesting bits!

 

If you want to contact me directly to ask a question or make a comment, my email address is pah@netcall.com.au.

 

Introduction

I've been working on this project about four years. I spent most of that time thinking up with and discarding designs. As of the end of February 2009, it is about two months away from launching.

 

Update

Ah, ha ha ha! At the end of Feb 2009, I was in fact nearly two years away from launching. As almost everything I am building is a one-off prototype to no design but my own, everything takes three times as long as you'd think. In October 2010 I am not launched but getting hopeful - see at the bottom for progress.

 

Anima -  the executive summary

Anima is a tacking double-outrigger with low-volume amas. The main hull (vaka) is a 2nd-hand David Pyne-designed fibreglass Tasman Twin tandem sea kayak - a large volume design. The amas are glass/epoxy over foam. The akas are telescopic aluminium tube.

 

Specs:

LOA: 6.46 m (21.2 ft)

BOA: 3.8 m (12.5 ft)

Ama length: 3.6 m (11.8 ft)

Ama volume: about 65 litres each (about 150 lbs flotation submerged, less ama weight of around 10 pounds) - don't know the percentage in traditional tri ama volume terms but it's probably down around 15%!

Sail area: 38 sq ft - (eventually, a second mast will likely be added with another sail of undetermined size.)

Akas: Al tubing - 50mm OD, 2mm wall/44mm OD 1.6mm wall. Max free span about 1.5 m.

 

I did a rough assembly the other day for the first time, temporarily held together with straps. This gives you some idea of what my finished craft will look like - note the flat wineglass transom:

 

 

 

Where I live

I live on the south-west coast of Victoria, Australia,on the well-known tourist route the Great Ocean Road.

I live near the lighthouse:

 

 

This stretch of coast can have fair-sized large surf - 2 metres is common. There is little or no protected water, and out to sea is Bass Strait or the Southern Ocean - both scary bits of water. Some of the coast is sandy beach, but a lot of it is rocky. Weather can change quickly and strong winds of 30 - 40 knots are not uncommon. There are a few lakes and navigable rivers within a 2-hour drive, but the coast is my main destination.

I want to be able to sail off this coast in any reasonable conditions - up to 20 knots of wind and 1.5 metre swell. I want to be able to cruise and get ashore safely in conditions far worse than that.

 

The original spec

I have always wanted a small single-handed cruising boat. I've raced dinghies extensively, and sailed keelboats, but I like a little cruising vessel.

There are no harbours and few boat ramps in my part of the world.

 

This was my original spec:

 

  • Sailing capability
  • One person handling, two person capacity.
  • Can be transported to beaches without boat ramps.
  • Handles well in surf and open ocean.
  • Reasonably fast.
  • Snorkelling platform.

 

(Maybe a developed sea kayak - sit-on, maybe with removable outriggers (maybe outriggers have the keel/daggerboard), unstayed mast and smallish single sail. All sailing gear can be stowed in hull while on board.)

 

...added to...

Needless to say, I added to this spec over the years. Items now include:

 

  • Fast setup/pulldown.
  • Lots of redundancy (and forgiving failure modes) for better safety and self-rescue.
  • Moderate cost.
  • Decent length (for surf management)
  • Not rotomoulded polyethylene (hard to modify) - so, wood or fibreglass.
  • Not sit-on (at least, some sit-in-ability.)
  • Possibility of sleeping/shelter onboard.

 

My personal rules for this project

I am allowed to make mistakes, even expensive ones - it's a prototype!

 

Some other design principles

Make as few permanent alterations to the kayak hull as possible. So far, it's down to drilling about 20 small holes (mostly in the deck) and one big one for the mast - maybe a few little ones for sail rigging. The idea is that I can tranfer the outriggers/sail rig to another vaka in future if required.

Oh, and try not to put holes/pins in aluminium tubing, especially in a stress situation. It's OK but it is asking for wear and stress concentration.

 

 

History

 

Early designs

I initially had little source of comparison for what I was doing. At various stages, had I had the money or the opportunity, I would have bought a CLC tri, an Easyrider kayak with sailing kit, a Windrider, a BSD BOSS kayak sail rig with inflatable amas, and just about any of Steve Isaac's (aka Watertirbe Chief) old rigs (I found out about his really interesting new Tridarka Raider design only recently - might still build it!).

 

But, living in Australia, you couldn't even get CLC kits until recently. I was scared of epoxy resin (I'm allergic to a few things). I'm a very modestly skilled woodworker, though I'm improving.

 

I bought a kayak cheaply - it was a Current Designs Storm single of rotomoulded polyethylene. Two years and hundreds of design sketches later, I traded it in for a fibreglass boat. I learned that it is really hard to bond things to polyethylene, and that I really wanted a larger two-person craft.

 

I bought a Australian David Payne design called the Tasman Twin. I had seen some of David's wooden kayak designs and I loved his lines. This hull, at least ten years old, was enormous - 6.5 metres long high volume hull with big bows.

 

At the kayak shop, they called it "the ship" - it dwarfed every other kayak there:

 

 

 

It also had a flat transom stern with a wineglass shape. This is very unusual in a kayak but perfect for retrofitting a chunky, dinghy-style removable rudder. I really didn't like the idea of those top-mounted kayak rudders for sailing - far too much leverage on the top bracket.

 

 

Designing and building the amas

The amas were the first things I designed and built. They were designed around my original Current Designs hull, but transferred OK to the Tasman Twin (except the huge rear hatch is a little obstructed - not as big a problem as you might think).

 

I used a program called BearBoat Pro to design the amas. BearBoat Pro is very easy to use, and works on minimising wetted area for the design paramenters you choose.

 

My design parameters for the ama were:

  • Low volume so I could sink them and right the rig in case I turned turtle.
  • Slippery for most angles so water turbulence couldn't get too much "grab".
  • Up-turned bow to reduce nose-diving (I really should have used high volume in the bows instead)
  • Minimum drag for design length.

 

Beause I knew little about wood-work and had designed my amas freely without regard to what you can do with a flat plane of ply, I decided to shape them out of foam like a surf board. But surfboard foam is insanely expensive. Much research yielded a fine-grain, high density styrene foam, very shapable, which could be supplied in sizes to order.

 

I cut out a central vertical stringer of marine ply which looked like the profile of the ama hull. With the help of a friend with a big bandsaw, I cut my foam blocks to vertical and horizontal profiles (so they looked the right shape from side on and from above).

 

Just made one teeny mistake. Each profile was a half hull, so I had to cut four for the amas - two right, two left.

 

Except I cut four left sides, and my amas are NOT fore-and aft symmetrical!

 

We got around this by simply "flattening" the curved side of two pieces - pulling them in to bond to the central stringer on the "wrong" side. This worked amazingly well, so much so that you can no longer tell which was the "wrong" side on the finished ama.

 

During this process I had some professional help. After bonding each half to the central stringer, we bonded a thick-walled piece of PVC tube vertically into the ama for each aka mounting point, into a cutout in the stringer so it became structurally part of the stringer. This created a potential bury of 140mm at the rear mounting point and 200 mm at the front mounting point.

I shaped each ama like a surf board. From my design program, I had printed out half-sections of the hull for every 20 cm, and every 10 cm at each end where the shape changed more rapidly. I glued the printouts to thin MDF, then jigsawed each half-section out. I marked the hulls for length, then pressed the female MDF half-sections into the foam along each side.

 

Here is the ama in the process of shaping, with the half-sections laid along the top at their measured positions:

 

 

I power-planed off the pressure marks in the foam, then did it again. After days of this messy procedure (I'm still finding bits of styrofoam in my bedroom) I had a good shape, which I longboarded to a pretty nice shape ready for glassing (I had this done professionally as I was still scared of epoxy at this stage).

 

After 2x4oz glassing, with further reinforcement around the mounting points and between the mounting points as a step-upon, I had light strong amas.

 

A couple of ama design decisions caused me much head-scratching later on:

  • In the hope of a more stable movement under load, I maximised the distance between the aka attachment points on the ama - 1.9 metres (just over 6 feet).
  • For various reasons (mounting in a composite foam construction, force analysis etc) I made the aka attachment points vertical cylinders (to accept a tube).

 

The akas

The akas caused more design headaches than any other part of the boat.

 

I had all sorts of trouble arranging the 1.9 m gap between mount points at the ama to fit with the kayak hulls I used - at one stage I was contemplating Al tube precision bent in two different axes just to make it all fit together! I found out it is mightily hard (= expensive) to bend thin-wall aluminium, especially if you are looking for tolerances of less than a degree.

I didn't even discover methods of creating akas by lamination of thin strips of wood until too late in the design process, though I did consider steam-bent wood at one stage

 

I eventually settled on straight, telescopic akas of aluminium, attached to the akas by composite elbows (of which more later).

 

The outer aka tube is 50mm OD,  2mm wall thickness, temper 6060 T5 (this is not ideal by the way - I would rather have 6061 T6 but at the time of purchase was considering bending curves into the akas - the harder alloy doesn't bend very well. I later changed this design but when you have spend many dollars on something that will do the job - you use it!)

The inner aka tube is 44mm OD, 1.6mm wall thickness, temper 6061 T6.

When the tube is fully extended to design beam there is an overlap of around 450mm of inner and outer tube. I intend to have a thin layer of glass (c. 0.5mm) bonded to the inner, covering this overlap (later change to two 50mm strips at either end of the overlap). This is to decrease the clearance, decrease stress concentration, slightly increase wall strength and remove the risk of Al-Al binding. However, I can reduce beam to 2.5 m, and sail with that reduced beam. I expect to do beam changes on land because it would be tricky to do this while actually on anything but the calmest water - but might try some experiments!

 

Aka mounts on main hull

The aka mounts are of 25mm marine ply bolted vertically through the deck of the sea kayak. One of the trickiest aspects of this was trying to work out where vertical was on a flowing curved hull design. I eventually just found horizontal (by floating the main hull and using a level) then decided that vertical was perpendicular to that!

 

Another slightly tricky issue was shaping the wood to fit he hull (both stringer on the inside and mount on the outside). I used gap-filling epoxy to bed the mount (using releasing agent on the hull).

 

 

 

The mounts bolt through to stringers which spread the load underneath the deck (yes, the kayak is  inverted in this photo!).

 

 

Each mount has a large lashing-point (big chunk of oregon) bonded to it extending slightly beyond the hull, and bolted horizontally through the hull.

 

 

 

I use big chunky SS/polyester ratchet tie-downs ( the strap is 25mm wide) to lash akas to mounts (not shown above):

 

 

The aka mounts would work fine with conventional lashings, rubber inner tubes or what have you. I'm using tie-downs in the hope that they are quicker to rig. They use them for OC canoe outriggers in Queensland sometimes.

 

Elbow pieces

So I have straight horizontal akas, and vertical mounts in the amas. I need a transition.

 

The elbow pieces create a transition between the horizontal akas and the vertical holes in the amas. They cover an angle of 96 degrees (to allow for 6 degrees of heel at nominal loads) with a straight of about 250 mm on either side of the angle - this straight is buried either in the ama or in the aka.

 

The elbows are made of hardwood dowel (cut in 14 degree wedges and end-bonded to create the angle). Here's one in the jig I used:

 

 

The wooden core becomes a former for glass tape wrapped helically around to a thickness of about 2mm - the idea is that most of the load gets carried by the glass, not the dowel:

 

 

The elbows are of two different sizes (two for the larger diameter aka, two for the smaller). They just fit inside the aka tube. 

I later built these up with uni carbon fibre.

 

Here is one in position - you can only see the actual elbow as the straights are buried in ama and aka. The blue elastic strap is not part of the final rig!

 

 

 

Holding it all together

I wanted to avoid using pins through the Al tubing to hold it all in place. I considered cleats and lashings, but eventually decided to use big chunky SS hose clamps at each connection point.

 

All the connection points (ama/elbow, elbow/aka, inner aka/outer aka) have an "outer" of aluminium tube, slit at the end so the clamp can bear. At each clamping point, the outer is axially cut at 6 evenly spaced points around the diameter of the tube. The cuts alternate between 40mm and 50mm, and have slight widening holes drilled in the inner end of the cut for stress reduction and to reduce corrosion points.

I really wanted to get cam clamps like those on bike seat posts, but couldn't find any in the right diameters. My clamps are screwdriver/wrench tightened, which is a minor disadvantage.

 

Because of all the clamping points (3 on each aka, 2 on each ama) there is an insane amount of adjustability - I intend to replace the four aka/elbow clamps with permanent bonds.

In normal use I will only adjust the two outer aka/inner aka clamps for telescoping of the akas for trailering, maybe narrow passages such as small rivers, and

berthing.

 

Rudder

This is pretty conventional - the profile is loosely inspired by Steve Isaac's Watertribe rudder. It has about 15% - 20%  of the area forward of the pivot point to reduce the chance of stalling. Currently it is a flat 4mm Al (5083) blade, but it has cheeks bonded to the blade stock to bring it out to 20mm. This is so I can make a wood/glass foil rudder some idle winter and still use the same housing.

 

Rudder blade with blade cheeks prior to bonding:

 

 

 

The rudder stock is not yet made but here is a diagram - you can see it has a dinghy-style pintle/gudgeon setup. I did a heap of design pics like this in CorelDRAW - not formal drafting, but they helped me to visualise things, and enabled me to print wood and glass fabric cutout diagrams.

 

 

 

Aside: bonding ply to aluminium

It is hard to expoy things to aluminium, because the oxide layer forms so fast (and the oxide layer is not strong enough to bond to). As soon as you sand aluminium, the oxide layer has formed - it takes literally seconds. There are etching kits sold to counter this, using muriatic acid I think, but I found another really cool and simple method on the net. I have tested it, and it works really well - used it on my blade stock cheeks.

 

Basically, you apply epoxy to the unprepared aluminium surface, then sand through it (like wet sanding) with coarse paper (40 - 60). The liquid epoxy stops the oxygen from reaching the surface of the sanded aluminium, thus no oxide layer is formed - you are bonding directly to toothed aluminium metal. The oxide suspended in the epoxy after sanding does no harm to the bond strength. You can then  happily bond the aluminium to sanded ply, or whatever else takes your fancy.

 

Had to share that with you - it appeals to my nerdy sense of elegance!

 

Leeboard - moulding fun for everyone

I bought a sail rig from Mark Balogh of Balogh Sail Designs - he makes very good quality gear. It cost an arm and a leg, especially with the Aussie dollar exchange rate back then, but I wanted something bullet-proof to keep me company on the lonely ocean. It included a beautifully made leeboard which attached to an aka. Update - I am considering carrying a spare leeboard on long trips.

 

To keep things simple, I wanted to attach the leeboard to my aka, but it was a different diameter to the one Mark's leeboard fittings were designed for - I had bigger amas and consequently larger diamter tubing. So I had to make my own leeboard clutch. I was getting so cocky by now I decided to build my own moulded part completely in glass and epoxy

 

Here's the diagram. The thick white thing is the thickness of the leeboard and the existing hole in it. The metal ring is an aluminium ring washer, which I made out of the same 4mm plate I used for the rudder.

 

 

Here's the mould, carved from ply - bit of a rough hack:

 

 

The first moulding came out really well (below left). The second was a mess (below left). I've done a lot of work on the mould which will hopefully improve its replacement.

 

 

 

I have now bonded these to the aluminium washers shown in  the diagram, reinforced with a lot of uni carbon fibre, fitted and painted.

 

 

Sail plan

 

Fairly early in the project, I decided to buy a sail, mast and centreboard from Mark Balogh of Balogh Sail Designs. Mark specialises in making all-points sail rigs for kayaks. His gear has a reputation for being bullet-proof, which suited me for solo sailing on an inhospitable coast. His sails have a zip reefing system. I bought the 38 sq ft sail (his largest) which reefs down to about 30 sq ft and 20 sq ft.

 

Before buying these sails, I also picked up a couple of small used windsurfer sails and a fibreglass windsurfer mast, all for about US$60. Again, these were pretty small - about 25 - 30 sq ft each.

 

I like small sails. I don't want to go really fast (although this Tandem Twin hull pushes really easily) - I'm a cruiser by nature. Also, in ocean conditions, I don't necessarily want to be hiking out all the time, and we often get pretty solid winds. I also want the sails to be unstayed, and furthermore I don't have that much bury compared with, say, a Dierking proa.

 

So I have rough sketches of a couple of tentative sailplans with three possible mast positions. Here's the single-sail version:

 

 

The Balogh sail is on an aluminium mast which breaks down into 4 sections for easy stowage. In this mid-mast position, there is about 35 cm of bury, which I hope will be enough. Also, the mast is attached to the aka, which gives lateral support and thus another few cm of effective bury. The only problem with this rig is that people will point and say, "Ha ha, look at the tiny little sail." Unfortunately I don't expect the boat to point very well with this rig - I hope to tack through about 110 degrees.

 

 

And here is the double-sail version:

 

 

As far as I can tell the centre of effort is not that different between the single- and double-sail versions. I'm hoping the centre of resistance is not too far aft of the centreboard, which is attached to the aka.

 

The forward mast position has about 37 cm of bury which I think is probably OK - it is reinforced at that point, and it's more than most kayaks offer.

 

The rear mast position has about 30 cm of bury - not sure if I'll need some kind of mast partner here. Unfortunately it can't be attached directly to the rear aka because that would put it through a hatch. It still penetrates a storage compartment, but will be in a glassed-in tube so the compartment stays sealed.

 

The windsurfer sail is on a cut-down fireglass mast, which I plan to reinforce at deck point with a tapering external FG reinforcement running about 30 cm either side of the deck,. Alternatively I might use the approx 1 metre I cut off the bottom of the mast as a stub mast - not quite sure how this would work.

 

And if I go really crazy, buy another 6061 tube for a mast, I could put up three sails:

 

 

This rig poses interesting sheeting problems!

Update: the likely outcome is to have three mast positions but probably only two sails at any one time. The fore and aft masts positions will be further spaced. This allows a schooner rig which leaves the deck area free (I'll be located near the rear cockpit), allows a single sail in the middle for heavier conditions, and also allows for a hammock tent slung between the fore and aft mast.

 

Some extra notes on the ama displacement and the rig in response to a question from Alex:

 

Hi Peter, I enjoyed reading about how you rigged your boat. I'm
>> working on a similar arrangement for a Pygmy Osprey triple. I'd be
>> interested in hearing how the rig and ama arrangement works out for
>> you. I was considering an ama displacement about 50-75% larger than
>> what you had and am wondering if it would be neccesary to go that
>> large.
>> Any feedback you can provide would be appreciated.
>> Thanks,
>> Alex

 

13 Sept 2009

 

Hi Alex

Not sure if I am the Peter you want, there are a few of them. 

So far I haven't finished rigging my boat - have a very busy contract at the moment so the kayak/sailing tri has been sadly neglected.

The Osprey is a pretty boat and not dissimilar to the double kayak hull I'm using in overall dimensions - a tad shorter and less voluminous by the look of it

Ama displacement is a much discussed question. I went for something I could sink with my bodyweight, as I may be sailing alone in ocean conditions and if I get capsized or turn turtle (heaven forfend!) I want to be able to have a chance at righting the boat alone without using any more special gear than a rope. Hopefully my boat will be finished by this (Australian) summer and I can go out and do some capsize tests in protected water to see how the theory works.

One disadvantage of my smaller amas is that I can't really step on them when tied up to a wharf, so have to find workarounds for this (eg ladder/gangplank from central hull, telescope one side so the pier-side ama is against the main hull etc).

Kayaks are pretty easily driven hulls, especially if not overloaded, so they don't need a massive sail area, especially if you are just cruising with you sailrig - this makes large amas not really necessary for sailing purposes, and larger amas might add to drag and weight a bit.

I partly based my design on a "scale up" of the volume of the Balogh Sail design (BSD) kayak sailing rig - I have a BSD sail of 38 sq ft, and the inflatable amas sold by balogh to go with this are about 30 litres each - less than half mine. Mine would be definitely on the small side if I was to use a triple sail rig, but would be OK for a double sail rig (using a small windsurfer sail of about 28 sq ft which I have). I plan to start with just the single sail and see how that goes - I suspect the triple rig I have on wikiproa will actually be more trouble than it is worth, though it would look cool!

I also kept my ama size moderate because I wanted to control the maximum static stress on the akas. If their displacement is about 70 kg each more or less, then that is the max static stress on the end of the 6ft lever arm formed by each aka and the main hull. Dymanic forces are probably proportional to things like profile (my akas present a rounded low drag profile at almost all angles) and to a lesser extent drag. These dynamic forces also tend to be smaller on smaller akas. I'm not really sure how strong my telescopic AL tube akas are, and I'm building to a design philosophy that says "be safe rather than really fast". Also I am not wild about my aka/ama joint design (elbows) but for a number of reasons to do with convenience, maintenance, speed of assembly, weight, profile and aka/ama design, it seemed the best workable solution.

Because you have a triple, mast location might be a little complicated if you have more than one sail. Can't comment on that much as I haven't rigged my boat yet. In fact, take all my comments with a pinch of salt - plenty of theory informed by wide research and good advice, but I still haven't sailed a foot in this boat!

 

 

If you want to contact me directly to ask a question or make a comment, my email address is peteyak1960@gmail.com.au. 

 

October 2010

The outrigger hulls are finally painted. Lesson - don't go fancy on a prototype. I used Bote-Cote system, a very good epoxy 2-part paint system made in Australia. It uses a high-build undercoat which you sand back to improve fairing. It looked OK after 30 hours sanding and four top-coats - not professional but OK.

I completed the centreboard rig, reinforcing the clutches with windings of uni carbon fibre. I also reinforced the elbow pieces with carbon fibre. Rudder and headstock is now complete, and all components are painted.

I tested my minimum beam (the akas are telescopic and adjustable) and it came to 2.490 metres. The trailering width limit in Australia is 2.5 metres so that worked out just fine. I can sail with minimum beam (straight off the trailer) or undo 4 straps and 3 clamps to extend to an "expedition" maximum beam of about 3.6 metres.

Instead of a glass overlap sleeve on my inner telescopic aka, I put two 50mm strips of glass spaced apart to build it up closer to tolerance - I added a third strip for the "minimum beam" sailing position. So it is designed for two sailing beam positions rather than an infinitely variable beam between max and min.

 

 

 

 

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Sometimes I need to do stuff to get whacked in the face by underlying
design problems.

I would like to say I pondered this as my kayak/tri/outrigger Anima
slowly sank off Bell's Beach, but actually I was scared witless and
desperately trying to find my damn handpump.

Executive summary of what follows:

I have a basic design problem which I found out the hard way - not
enough freeboard for my current hatch setup to keep water out in some
conditions.

The long version:

I was setting off on a 3-day coastal-camping ocean trip, my first sail
of more than a couple of hours. It was about 10-15 kts wind, sloppy
short wind waves, quite confused, around a metre high.

It went really well for the first leg from Anglesea to Point Addis,
though the boat sat very low in the water with all the camping gear and
20 litres of fresh water. To lay my course it was mostly upwind, as high
as I could point. For the first timke I had a GPS working (I love that
thing) so I could see I was going upwind at about 5 -6 kmph and reaching
at about 10-12 km/ph - hardly stellar performance but it seemed quick
enough to me, and a modest tide was against me.

But as I was passing Bell's Beach (of world surfing fame) I noticed
that the boat was definitely sitting lower in the water. No need to
panic, I thought, I'll just sheet in the mizzen, ease the foresail and
let the boat hold itself to wind while I check inside the hatch. Then
things started to go to pieces rapidly.

(To understand the next bit: My vaka used to be a tandem sea kayak.
There is a fore hatch to the fore sealed compartment which I didn't
touch, two cockpit hatches I made to cover the original fore and aft
cockpits, and an original rear hatch to the rear sealed compartment.)

Sure enough there was water in the hull - at least 60% full in the main
central compartment. I started to panic and looked for the handpump
which I had packed somewhere inside the hull - but which hatch? I opened
the front cockpit hatch, couldn't find it. Opened the rear cockpit
hatch. Immediately water started washing in from the sea and my drybags
started popping out. Really panicked now, I opened the rear hatch (which
I swore never to do at sea. Immediately the rear compartment, also more
than half-full, filled completely. I was an idiot and I was going to
die, or have to set off the EPIRB - not sure which was the worse prospect.

Then the rear hatch over floated away. Did I mention I had already lost
a hatch cover in a previous trip? Slow learner.

By now the rear half of the deck was completely awash. I had finally
found the pump, forced most of my drybags back in the hull for whatever
floatation they might offer, then started pumping - a waste of time
because even with the mid-hatch partly on, more water was getting in
than I could possibly pump out. Meanwhile I was drifting steadily in the
onshore wind towards the cliffs at the south end of Bell's.

After a short time I gave up on the pumping, realised I didn't seem to
be sinking any further and decided to see if the boat would still sail.
With most of the boat underwater, both amas deep in the water and the
rear two thirds of the deck constantly awash, amazingly it still sailed,
cracking up to about 8 km/ph on the reach. My sails were probably moving
about half a ton total boat weight through the water at this point. Even
so the boat felt relatively easy to sail except when draggy deck
infrastructure like aka mounts (usually well above water level) slammed
into waves. I sailed back to Anglesea, freezing (because I dared not
search for my spray jacket) and made it to the boat ramp at sunset.
Luckily I had friends to come and help me bail the boat to the point
where I could get it out of the light surf, de-rig and trailer home.

Lessons:
1) A fundamental design problem with my craft which should have been
obvious but needed a longer sail, a full cruising load and nasty chop to
really bring home (I'd had only modest water into the hull in my
previous three sails) - there just isn't enough freeboard for rough
water, and I fear that my very large cockpit hatches and large rear
hatch will NEVER seal well enough to keep out the water that sluices
over the deck. There are various possible kludges - have a permanently
mounted electric or hand pump for the centre compartmen (at present I
can only pump through an open hatch), install venturi-effect drainers in
the hull bottom - but a proper design would keep the water out in the
first place.
2) Have the safety gear, pump etc where I can get at it WITHOUT opening
a hatch. Spray jackets and drinking water count as safety gear. But
ultimately this would not have got me out of the situation caused by 1).
I was underprepared and rushing for a very small circumstantial window
of opportunity to launch for this 3 day trip - and I knew it and should
have simply cancelled - no excuse.
3) My boat, despite its design flaws, has a serious amount of
redundancy. I know now that I would have to flood all three conpartments
to have even a chance of sinking, and that it can sail quite nicely
underwater.

Some possible solutions:
1) Replace the vaka. It is a bit on the heavy side, and being a sea
kayak with a sloping deck, can never have much freeboard and will always
invite water over the deck, especially driven at sailing speed through
chop with the extra weight of amas, akas and sail rig. (This would,
however, be a heart-breaking lot of work and expense.)
2) Add freeboard by remodelling the deck of the kayak, at least the bits
encompassing the cockpit hatches. This would be complex and add weight,
but might provide some other advantages. Maybe replace the rear hatch
with one or even two 8" screw-in type hatches to access the long rear
compartment (I have plenty of other spots to put big things) so only
the cockpit section of the boat would be enclosed with extra freeboard.)
3) Use the sea kayaker neoprene spray skirts I have on the cockpit
hatches, with something inside them (not me) to hold them up.

Pete

Comments (6)

paul.lis.bowker@... said

at 12:38 am on Mar 16, 2009

To me the three sails look much too complicated, what about a single mast, put 2 shrouds .. polyprop rope. to the amas or kiatos, and a forestay, then fly a small jib. The jib cab be backed to help you tack. If you can lower the main then running downwind under jib alone will be safe and easy. Nothing highly tensioned. An opti dinghy has 35sq ft of sail so I don't think the Balogh is too big espescially if reefing is easy.


With shrouds the mast bury is no problem.

Paul Bowker

Peter Haydon said

at 2:15 am on Mar 19, 2009

Yeah, I thought about that but there are a couple of design constraints which means this would work too well for me.

Firstly, I want the masts to be quickly completely removable and stowable while at sea - this is in case of really nasty squalls where even bare poles are too much, and for difficult surf landings. Because the main hull is a kayak, I anticipate making surf landings and outings using paddle more than sail, unless conditions are pretty benign.

Secondly, I think quick and flexible rigging is really important to the useability of the boat for me - I want to keep actual rigging time to a minimum. The longer it takes to rig, the less I will use it.

For both these reasons, I'm not keen on a stayed mast - quite tricky to derig at sea while staying in the boat, and longer to rig and set up on the beach.

The three sails are more complicated, true, but I would most often be using one sail only - extra sails are for lighter winds. Not sure if I would ever use the three-sail combo - we'll see.

dstgean@... said

at 12:44 pm on Mar 23, 2009

You might want to put some unidirectional glass or carbon on your ama connections as the glass fibers are short and potentially a weak spot. On my Ulua I carved a block of wood to fit over the ama and made a direct attachment that I could lash quickly. As a no hassle backup, you could add a lashing to your ama to aka.

Dan

Peter Haydon said

at 4:10 pm on Mar 23, 2009

I've never used carbon so I don't really have a feel for it's strengths and weaknesses. I've got some glass tape with a carbon thread down the middle which I have been thinking of using to reinforce the ama-aka connection. With this and/or more fibreglass, I'm building up the exposed section of the elbow. I'm also doing a resin pour with the bury of the elbow inside an aluminium tube (coated with releasing agent) of the same diameter as the aka/ama points - this is to even out stress loading within the aka tube (and the ama mount tube). There will be a stress concentration at the point where the elbow enters the tube, but I can't think of a simple way round this without completely changing the design.

The lashing backup idea is good - I'd prefer not to mount it permanently, but I've been planning to always carry enough lashing cord to replace all aka/vaka straps, and to jury-rig an aka/ama connection - this last would be clunky because the ama is all smooth curves but hey, if it gets you home...

One thing I've been wondering is, "Where do I want it to break?" Hopefully not at all, but if I'm capsized in surf with one ama in the air and the other being pounded on the bottom with the full loaded weight of the vaka, I think I want the connection elbow to break before the ama breaks in two. Just a cheerful thought :-)

Peter Haydon said

at 12:09 am on Sep 13, 2009

Follow up to last commen about elbows:

I've put uni directional carbon along each elbow as dstgean suggested, four strands on the large elbows and three on the small, with an extra built up of carbon on the bends of each elbow piece, tapering out to avoid stress concentration. I tried the resin pour idea - had to cut the AL former off, but it otherwise looks ok. Made some elaborate slit moulds, then just decided to wrap 50mm glass tape around the ends and close to the bend of the elbow piece - lighter, more controllable stress concentration at the bend, fits the aka better and much, much easier to make compared with a resin pour into an Al mould.

Radian said

at 3:04 pm on Sep 30, 2009

hi peter
great site.i have just purchased a 2nd hand valley knordkapp sea kayak for my trimaran project
and its great to see someone else doing it.im,e going for a reefable main sail (prob a converted large windsurf sail)
and a front jib.i was stuck on how to fix the aka,s to the kayak,but i like your removable strap idea-fantastic
so i have lots to do over the winter months,i should have it built for summer 2010
i have a pb account so will record my progress and send you the link
all the best
tony
essex
england
united kingdom

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