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Two Dierking Tamanu Canoes

Page history last edited by dstgean@... 11 years ago

Dan St. Gean and Brian Rugg, Illinois 


We're building a pair of Tamanu canoes designed and prototyped by Gary Dierking while on vacation in Fiji.  Scroll back in his blog for Easy Rider entries--awesome stuff!




(From Dan) This page will be mostly pictures of the build Brian and I are doing right now.  So far we have constructed the 6 bulkheads for both canoes and made the side panels for the canoes as well.  These will get epoxy sealed on the inside and outside with a glass layer on the bottom extending over the chine.  I'm building the sides out of 4mm--as is Brian on the one he's building. 


Our plan is to each end up with a Tamanu single outrigger to keep at home, while having the option to join each outrigger into a cruising double canoe of some capacity.  This has been brewing in my mind for a long time.  I originally though I'd do it with my Ulua featured on another page here Dan's 21' Ulua and written up in a Duckworks piece titled “Boats can be crazy things”.  It can still be found at http://www.duckworksmagazine.com/05/projects/crazy/index.cfm   However, the open nature of the Ulua doesn't necessarily make for the best cat hull.  The Tamanu corrects these potential problems by being divided into three watertight compartments and being fully decked.  The self bailing footwells are a nifty feature as well.


Here is Gary Dierking’s Tamanu design as a single outrigger. It can also be built as a double outrigger 
 or a double canoe.


When planning this build, I thought of doing it myself, but my crew on the Texas200 got into it enough that he wanted an outrigger of his own.  We are going to be using them both as single outriggers AND as cat hulls with my Hobie 18 rig and details.


That's Brian on the tramp prior to putting the H18 together (enjoying a novel from that literary genius, Clive Cussler). 


We found the boat fun and fast, but overloaded and WET! Note the lack of freeboard.



Brian helming the second time ever on the 18—in 20 to 25 knot breeze with higher gusts.  Note the lack of freeboard aft.  The outrigger hulls we will be using have 2' of freeboard both in the bow and stern unlike the Hobie which has about 2' in the bow and 11" in the stern.


It was sometime after the T200 that we decided to do a more cruising oriented cat.  I gave Brian several design ideas and let him choose the final design.  He wanted to do a simple boat for his first build and chose Tamanu.  I was already planning on doing a Tamanu (or a Chris Ostlind cat design called Neo, pictured below) based on wanting a cat with more displacement both for cruising and for party barging with the family.


A really cool cat to be sure...but could I get it built before the T200?  

Tamanu won out for the individual outrigger capability for Brian and

the speedy and simple build.  Chris' equally cool A64 might have

worked as well.  So many boats to build....



This bad boy is what we decided on doing.  It fulfills my mission of having a two person canoe, a sailing outrigger, a double outrigger, and a double canoe.  I'm so excited that Gary came up with this design! If you havn't read about it's genesis or stopped by Gary Dierking's blog do so without further delay.  Brian is also psyched about having his own outrigger sailing canoe when not in double canoe mode.



(From Brian) After a number of "gentle" reminders from Dan, I have finally uploaded some photos of our progress.  I am attempting to document the build every step of the way.  Since I am the photographer most of the photos will feature Dan, but don't get the impression that I'm letting him do all the work! 


I am very new to sailing and to boat building so I'll be offering up my perspective as a newbie as the blog moves forward.  If I forget to identify myself when posting comments, you should be able to easily figure out who is who by the terms used.  For example, while Dan may refer to the back of the boat as the "stern," I'll probably just refer to is as "the back of the boat."  You get the idea...




Bulkhead assembly 



I lined up the bulkheads to get an idea of how they'll fit into the hull. 



Side panels


Dan laying out the stringers to assemble a side panel.



(From Brian) Dan and I decided to go with a butt joint to connect the three sections of each side panel. We used epoxy to glue the joints together.  As you can see from the photo below we needed a lot of weight to flatten down the joints after applying the epoxy.  Eventually, Dan raided the school's weightlifting gym for some 45 lb barbell weights. 

(From Dan)  Got 'em back to the weight room too.  That was a workout!  The shop and the weightroom are on opposite sides of the building.  We went with WAY oversized butt blocks since the Tamanu design call for 8' panels front and rear with a 4' piece in the middle.  This 4' piece places the plywood joints in the cockpits for all to see.  Slave to vanity that I am, I didn't want a butt block cluttering up the view.  I also didn't want to scarf 4mm panel sides.  Now the cockpit sides are a bombproof 8mm thick which is good for those klutzy moments. 





After the epoxy dried we mocked up the hull with the bulkheads to check the fit. 


After we epoxy the side panels (no fiberglass...) we'll be ready for the next phase: Assembly!


(Dan) We've got the bulkheads epoxied as well as the interior of the side panels.  We are hoping to get the exterior epoxied tonight as flat panels (no drips) and then we'll be gluing them together.  We'll be glassing the bottoms of the outrigger hulls, but not the sides.  We shouldn't experience checking since we're using 1088 ocoume ply.  On to assembly!  Any hints on how to accurately assemble 6 bulkheads before the epoxy kicks?  I'm thinking of starting with the two bulkhead 3's (aligning, gluing, screwing, and clamping them) and onto to BH 2, 1 and finally bow and stern.  Good idea?


Well Brian and I managed to get two hot coats on the hull side panels with a squeege laying it on thin first coat and then squeegeing (is that a verb?) lightly and rolling a second coat on.  With almost 160 square feet of hull sides, the aroma of epoxy was a bit much and we bolted prior to adding a third coat.  We'll sand and do the third with some fairing compound.  It is amazing how much weight three thin coats of epoxy adds to a panel.  Like Gary says on his site, I don't believe this hull is the best for cartopping--unless you've got a suburban beater like I do.  Even then we'll be mostly trailering this beast. 


After sanding the bulkheads on Sunday for one of the hulls, I hit them with a third coat of epoxy.  I managed to get 5 of the 6 done with one mix of epoxy and subsequently managed to bugger up a small mix of epoxy even though it is 2:1 ratio.  It turns out that it partially kicked and got semi hard, but wouldn't cure.  I scraped the mostly thickened sludge, looked up how to deal with the problem online.  Advice?  Scrape.  Then laquer thinner, acetone, or alcohol.  Clean up the mess and wire brush it to get anything else off that will come up + add a bit of tooth for the next coat (which will happen Friday the 13th--been a bad one so far...  Hopefully the 14th won't be so bad).


Assembly should be this coming weekend along with attaching the bottom panels.  More photos forthcoming.


Well Brian was able to get to the shop on Sunday and we were able to get one hull together.  We had a bit of a problem with twist, but it worked out once we used screws rather than clamps.  Epoxy is slippery stuff and the bulkheads didn't want to stay square once clamped.  I think for the second hull, I'm going to prefit the bulkheads, screw the mess together and then simply back out the screws and use a sealable baggie with the corner nipped off to put the fillet in place.  I've got to add the pictures and then it will be real.


Four panels stacked in the shop. 





Here's the first of the two put together.  We had a bit of an alignment issue at first while everything was clamped up.  If I'd remembered to reread the assembly manuel, we'd have had an easier time of it.  In the end we used screws just like the manuel said to.  Hull #2 will benefit from experience.  That should get put together this week or weekend.


You can see some of the alignment issues we were trying to resolve.  Keeping the stems flush top and bottom, meeting in the middle and on centerline is a bit harder than I thought.  A string line would have helped here.  Additionally, starting in the middle and working from the ends is not the order I'd do it in again--indeed, we reversed the order for hull #2.  However, I didn't get the bow plumb in attempt #1.  So, I got to try it again.


On Dan's boat, he got the stem screwed together and found it had been screwed together with a bit of twist.  Time for a redo!


Both boats in various stages of assembly.



Brian beveling the stringers to make them flush with the bottom.  I should have prebeveled these on the table saw and saved a bit of work, but a power planer made it pretty quick nonetheless.  The belt sander was for final touch ups.



Hull #1 with the bottom getting epoxied and screwed on.



Bow view of hull Number two after gluing and screwing the bottom on.  Flipping and smoothing the fillet will hopefully save some interior sanding later.  It doesn't have to be perfect, but smooth enough to not snag drybags and arms reaching in for stuff.



Both sterns.  Note the different bulkhead materials in the two boats.  The lighter one is the 6mm underlayment while the darker one is 6mm occoume.



Both stems from down low.  These boats have huge volume!  I'l bet each hull to the 12" waterline is equal to my whole Hobie 18.  That said, I think a cruising load could easily be only about 6" of draft. 


(Dan)Well I got the deck stringers started on my hull.  I will be adding additional stringers to the seating areas to make the deck a bit more bomber at the expense of a bit of weight.  Brian also cut out footwell stringers and ply for the footwell bottom.  We're going to add stringers there too to make for a really strong floor.  All this adds a bit of weight, but should make the hull really strong where we sit and stand most. 




Starting to feel a bit of pressure to get going at the T200 is the second week in June.  Lots to do in the next 7-8 weeks.  We'll try to cut down on the overall work load by trying to reuse everything possible on the Hobie 18 for double canoe use and waiting to construct the other single outrigger stuff in July after the T200.  I'm getting psyched to get the deck on! 

This is the undersides of the aft decking.  Once screwed down we used a router bit to trim it flush.

Gotta do some calcs to see where the hull beams will attach when in double canoe mode as we will likely reuse the H18 beams and make an attachment for them.  The H18 has 84" from bow bridle to mast step and about a foot of bow in front of the bow bridle attachment.  The Tamanu has 83.5" from edge of the bow to edge of the first cockpit footwell.  Will the loss of bow area make for more trouble in pitchpole over the bow situations?  Will the additional bow volume offset the loss of length?  Should I scootch the attachment point aft to the back of the front footwell and now have lots of room up there?  I'll still have lots of boat as it's still 20' long instead of 18', so the shift back shouldn't really hurt anything.  I do have to do something with the mast step first for the boats in single outrigger mode before the decking goes on.  I'll do that according to plan.


I did a little calculating and found that the hobie 18 has 16" from the bow back to the bow bridle, 84" from bow bridle to mast step, and the spreaders are swept 20 degrees.  The tramp is 86" long to the aft beam.  To adapt the geometry to the Tamanu hulls while using as much H18 as possible I'm thinking of moving the front beam aft of the front footwell and giving me 9' to the bow instead of 8'2" like on the H18.  The other option would be to tack the bow bridle to the stem and have the front footwell 84" to the bow.  That would be lots closer than the H18 setup since I'd have no additional area in front of the bow bridle.  I'd rather have some extra bow out there to resist pitchpole.  It also makes for bulkheads right at the beam locations--good for strength.  Pictures soon!


4/14  I got some more epoxy and a bunch of hardware from Duckworks including a bunch of hatches.  I'm psyched to get building.  I have the deck stringers set on my hull.  I'm going to do the rest of Brian's, so we can mess with the mast step, deck blocking for the mast, and getting the thing decked!

We added stringers to the middle of the footwell in addition to the sides to eliminate flex.  Small weight penalty for huge strength gains. 

4/15 Bought some canoe stern pintles from Chuck at Duckworks designed for the 3/8 pin that the H18 rudder uses.  I would have returned the canoes style ones that I bought, but my wife mistakenly threw out the box with the whole mess in there.  Bummer.  Now I do have all the stuff I need to get finished short of paint.  I'll get cranking this Sunday and insert pics of the progress.  At this piont I will have five 8" hatches and one 9x17" hatch in the canoe.  What a world of difference that will be compared to the one 5" Hobie port on the last trip!

Brian epoxying the undersides of the aft decks.  In retrospect it would have looked good to have Gary's recommended hatch size in the aft section, but after struggling with the 5" hatches on the H 18 we went BIG!



Aft deck on Brian's hull Glued and screwed.  We had to place screws every 6" or so to keep the edge flat to the stringer.

Both aft decks glued and screwed.  You can see the center stringer in the hatch locations.  Once the epoxy set, I cut that out for the hatches and put a screw in the edge of each free hanging stringer end.



More pictures forthcoming, but the mid deck and both footwells are in!  I have to noodle the setup I want for the mast step today and then get that installed.  It's tough to find doug fir rather than the crappy SPF that most everyine carries.  The DF porch flooring is the one exception--clear and in 12' lengths.  However it only comes in 3" widths.  I need 5.5" for the mast base.  I found some clear DF at Lowe's!  I'm still not sure which rig I'll be using for this boat solo (not in double canoe configuration).  I'm thinking of doing a stub mast rig or going for the Raptor 16 style rig depending on getting a sail of that sort.  Roller reefing sounds so good.  If I use my mast that I currently have, it is too heavy to step at sea or sometimes even at the dock.  Brian's boat does not have that difficulty since he has a nifty Sunfish lateen rig.


A shot of the sterns with decks cut, screwed, and glued.  Hatches also cut and mocked up.


Footwell with hatch on the aft face. 


Both canoes with some deck on, Brian's bieng further along with footwell cut and mid deck cut as well.



Stern false stem glued on.


Epoxied in footwell with fillits around peremiter.  Thinking about glassing it as well for abrasion resistance.


Both mast steps glued in.


Mast base glued in.  Added stringer in the middle to match chine log thickness and make a mini box beam out of the structure. 


Mast base and deck step in one shot.


Both hulls from the bow showing hatch locations and mast structure.


Foredeck cut and coated.  Ready to install tonight.  That will be it for the decking.  On to the details!  Hull glassing and other fun stuff.


Here's a shot of the dashboards attached to the decked hulls.

This is the bow view of the hulls.  Less than a month to go before the T200!


Brian glassed the bottom of his with 6 oz cloth, but a few air bubbles that will need to be filled.  He really does some nice glass work.  My prep work left a bit to be desired though.

Bottom glassed.  One more to do!


I spent the afternoon sanding and prepping my hull for glass, shaping the stem and stern, filling any voids in the squeeze out between the hull and bottom, filling screw heads, etc.  Hoping to finish the prep and glass by this weekend.  I hope I have enough glass to do my boat....


Current items on the To Do List:

  • cut and attach bow false stems--done 5/7 
  • cut (done 5/8) and attach dashboards--done 5/9
  • glass bottoms--Brian did that 5/12 at least to his hull.  Brian added fill coats to his glass 5/14.  I glassed and filled the weave of my Tamanu Sunday 5-17.
  • disassemble Hobie to nab parts--done 5/20
  • Got H16 tramp beams to hold tramp sides.  Will bolt to hull sides
  • dragged H18 hulls into the garage--crap, those things are heavy!  The Tamanu hulls are not much different despite being 2' longer and massive by comparison.
  • make beam attachment mould and parts--began to make mould today 5/21.  Started the mould and proceeded to allow epoxy to drip onto my H18 beams--that was fun to get off.
  • add Hobie hardware to allow rig conversion to the Tamanu--beam mounts well sorta--we got the outboard bolts through the deck and need to fabricate the inboard lashing points, rudder hardware, sidestay and headstay attachment points, & tramp attachments
  • get a paint coat on the boat after fairing the hulls--might wait until after the 200--might roll on some varnish or rattle bomb it for a bit of UV protection 


I'm hoping it can all get done prior to the Texas200!  We'll have to be productive in May.... 


Well it's been a month since I've updated the blog.  We must have been productive enough in May to get to the Texas 200 since we got there with the double Tamanu/Hobie 18 and both started and finished the event.  We had a bit of breakage, but the parts that broke were all Hobie.  I think in general the plan was sound since the event was a success.  We could have had a better ride if we were further down the road construction wise in the project, but we managed to finish in relatively fine style.  Most of the trip was under severely reduced sail to keep the boat from breaking, but that seemed prudent as we were 80 miles from civilization.  We topped out at about 12 knots under main alone with major rudder drag from too much rudder toe in, and surfed at 9 knots under jib alone.  We had three rudder failures--luckily one at a time.  We also broke the main beam beating into 2-3' waves with about 20-25 knots of wind.  The breakage was in the tramp luff grove where the extrusion was welded or something.  As a result we really tried to reduce the stress on the boat for much of the event.  I'll give a trip report on a day by day basis in a link here, but this page will be mostly about the "completion" of the double Tamanu/Hobie 18 and later this summer the hopeful completion of the two single outrigger Tamanu canoes.  Pictured forthcoming on both the construction progress as well as T200 shots. 



Well the boats sat for a full year... that stinks.  After a full blitz of getting them done for the Texas 200, we coasted this year with other priorities.  I had a boy in April and that eliminated me from doing a trip in the summer.  Brian was crazy with work...


Now, however, I'm thinking of finishing the boat in a manner that will allow a nice camp cruisable catamaran.  I have not decided among the three iterations rolling around in my head though.


They are:

1.  A narrow beam cat with a small rig pirated off of the Ulua viewable here on wikiproa.  It would be narrow enough to fit in the garage--so 7'10"?

2.  A narrow beam cat that is 8'6" wide and uses the larger rig of the Hobie 18.  It would need wings and the rig would need two reef points to make for a safe cruiser.  Alternately, I could use the Ulua rig, but it is a bit underpowered.

3.  A folding version along the lines of Woods Wizard without the pod.  It would be about 11' extended and 7'6" or so folded.  Unlike Woods version, this one would ride on its trailer on the hull sides which are flat panels.  It would also use the Hobie 18 rig.


Thoughts?  Comments?






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Comments (2)

Kevin said

at 9:29 pm on May 12, 2009

Go man go! Men. Go men go. You know what I mean.

I'm still messing about on the inside of my big hull, but I'm about to kick it into gear and put the lid on, and get the thing back together. Honest. Less than a month, eh? Boy.

Looks good, keep working!

peter said

at 11:02 am on Oct 27, 2010

Dan and Brian, your post was the inspiration for my own double canoe project. Have you gotten further along in the build? Post pics!

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