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Leon's older stuff

Page history last edited by Leon 9 years, 2 months ago

What follows is older content that I moved from my main page to keep load-time reasonable.

 

21st of February, 2009:

Here's a shot of me paddling over the ama side. It seemed to work at the time but I didn't try it for very long. At left is me sitting on the crossbeam and paddling

over the other side. This seems comfortable with my long paddle, but I might think otherwise if I had a movable thwart to sit on in the hull.

20th of February, 2009:

Following proa_file discussion, here are some photographs of my potential sleeping accommodation. The space available is 230x85cm, with 22cm high sides to stop me rolling out of bed. In the shot below I'm reclining on a foam pad with a pillow against the raised bulkhead at the end of the cockpit. I should glue pieces of that foam to the seat boards permanently, and to the footwell cover panels when I make them.

Above right: This shot gives an idea of what the footwells are like. I'm thinking of making a slatted floor to keep things out of the inevitable bilge filth.

Above: Another view of the cockpit area. Just visible through the cut-out bulkhead at the far end is the screw-in hatch which gives access to the adjacent hull section.

Here's a cheap little single-walled tent I bought. It doesn't fit sensibly but perhaps I can make it work. If I just squish it into the cockpit it's actually pretty habitable and tent-like inside, but it looks awful and probably would be unpleasant in the rain with all that saggy fabric and no fly.

 

3rd of February, 2009:

Some new details:

Above: Here is one of the rudders and the side-hull mounting. As you can see everything is all pretty ugly at this stage. I want to go sailing. If it works I'll make it pretty.  

 

Above: One of the nifty over-centring levers that hold the rudders in the down position. The head of the lever is supposed to clamp a line led through the rudder box to the upper leading edge of the blade. When pulled forward (left photo), the lever is teetering on the edge of instability. The tension in the down-haul line makes it tend to release, but the little plastic clip is enough to hold it in position. If the rudder strikes something unforgiving the clip is overcome and the rudder can kick up. The other cleat is for the line which holds the rudder out of the water when not in use. The confusing yellow rope is just holding the assembly in position while I sort the whole mess out.

Above: The view from the cockpit. Standard tiller extension fitting articulates the curved aluminium tiller to the PVC conduit extension.

 

Above: My experimental Ug-Leeboard™ system. The rudder-boxish thing should flip automatically during a shunt, allowing a directional foil to be used, and moving the CLR slightly aft. You can tell it's a prototype, welded mild steel, string, electrical tape and foam. I wonder if it will work? I'll have to trim the top corner of the foil so it clears the windward stay.

 

 

31st of January, 2009:

Here's an update on what I've been doing. I've made a sail and some spars, they're roughly together but need some adjusting to get things looking right. Steering is pretty sorted too, I've gone with beachcat rudders mounted to windward of the main hull. On to the photographs:

 

Above: The poorly rigged boat from two angles. Clearly the sail needs to slide down the yard a fair bit. The windward stay is also excessively extended in these shots. You can make out the mountings for my side-hung rudders, nothing innovative there.

 

Clockwise from top left: Yard heel, mast head, mast base and boom jaws.

 

Above: The complexity at the centre of the ama.

 

 

 

19th of December, 2008:

I've let this project sit idle for several months and now I have a bit of time to get back into it. To refresh my thoughts about the design, I threw the pieces in the river and went for a paddle. My guesses about buoyancy seem to have been reasonable. The boat feels very nimble on the water, but it's difficult to make it turn quickly.

 

 

11th of February, 2008:

I'm trying to work out the cockpit and seating arrangements. The fore/aft beam you see is a hollow box beam and is stupidly overbuilt like the other beams. Never mind. Those little diagonal braces really stiffen up that leeward panel but will interfere with sleeping accommodation. It's probably a long while before I'll need to worry about that though.

 

 

 

5th of February, 2008:

I'm working on a couple of paddles. Oregon shafts, pine blades. The longer one is intended for steering and the other for propulsion but really I just guessed the shapes and proportions. I've only shaped the steering paddle at this stage.

 

Update 23rd of January, 2008:

 

Major Progress!

Well actually the only thing I've done since yesterday is glue up the leeboard bracket, but it dawned upon me that all the major parts are finished enough to do some lawn paddling and see how it all looks assembled.

Here’s an update on my progress as of the 22nd of January:

 

The 6.9m hull is mostly epoxy coated inside and out, decked and has dagger-cases in place. These may or may not get used.

I’ve started some rough fairing of the bottom but I don’t think I’ll take that very far. I hate the poisonous dust and I won’t be racing anyone.

 

After days of scraping, smoothing and epoxy-coating I can finally say the crossbeams are done. I really didn’t expect them to be so time consuming. The web is 9mm plywood. Flanges are strips of timber known as "Oregon" in Australia. I think this is also called Douglas Fir. A thin cap strip of pretty pink flooded gum covers the edge of the plywood web. I'm now convinced that these beams are a bit over-built, but I'll be happy to not have to worry about breaking them.

 

 

While I was fussing over ama designs, my copy of Gary’s book turned up. I decided to go with the simple method for building a diamond section ama he describes, changing the proportions slightly to suit my boat. That ama was the easiest part of the project so far, by a large margin. I’m working on a simple mount to allow a leeboard to be attached to the ama.

 

 

Here's an idea I had for a leeboard. It allows an efficient directional section to be used and has adjustable angle of attack. It would pivot out harmlessly when aback, kick up in shallow water and could be self shunting.

There are more photos in proa_file 6.

 

 

 

Here are a couple of photos of my first proa.  4.3m single chine main hull, deep vee ama. Plywood hulls, solid pine crossbeams. Teenage design and construction. I think this was late 2003, or possibly 2004.

 

 

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