One Man Dayak Part One .... this plan set is still a work in progress!



The written part of the Dayak plans is not finished and possibly (probably?) never will be. The dimensions are here. This is enough information for an experienced builder to work with but not for the beginner.

This one-off fiberglass construction tennique is well suited for the hobby boat builder. This is not a mass production technique. There is only one Dayak in existance. I built it about 5 years ago (now 2017 as of this edit). I used a one-off all fiberglass technique where I built a boat-shaped plug out of wood scraps and cheap AC construction plywood. Then I covered the plug with thin 4mil visqueen. Then covered the visqueen with 3/4" Plascore honeycomb core material. And then covered the Plascore with fiberglass. Popped that off the mold. Straightened up the hull (which always comes off the form somewhat crooked) and fiberglassed the inside. And then built a deck.

For the first two years I bolted the deck down onto a 1/2" inch closed cell foam gasket. Then I glued the deck down permanently. That was a mistake. The removable deck was better. I like decked boats a lot. I will never build an open boat again. I will never permanently fasten a deck to the boat either. Bolt-down decks work and it's a lot more convenient to work on the boat when you can take the deck off.

I built all fiberglass over a honeycomb core. The Dayak could be made with 3/8" inch marine plywood (or its millimeter equivalent) and soaked with oil. Or it could be made with plywood skinned with fiberglass, stitch and glue style. A Plascore boat is the same as a stitch and glue plywood/fiberglass boat, where the only change is substituting honeycomb core for the plywood.

Fiberglassing skills are essential in the construction of the boat, at least if you don't go the all wood way. Epoxy resin is used for all the gluing in the boat as well as for fiberglassing. There are a number of epoxy resin systems on the market that are suitable for boat building, but these instructions assume the use of Gougeon Brother's WEST SYSTEM epoxy products and/or Raka Resins. Read through the entire text of these instructions before beginning any work.

The Montana Riverboats Dayak is a one man boat vaguely similar to a small one man pontoon raft. But there are important differences. Pontoon rafts I am familiar with tend to be narrow and equipped with relatively small oars. The Dayak is wide and it uses big oars. 8-1/2' foot or 9' foot oars. The Dayak is wide and stable. I often stand on the boat while it is drifting (not in big water). The Dayak has consiserable dry storage below decks too. Most of all the Dayak is stable and very fast. The Dayak is the fastest boat I've ever rowed. One man pontoon rafts have their place. But now that have my Dayak there is no way I'd ever go back to a pontoon raft.

Part One Tool and Material lists

Plascore -- (800) 630-9257

Call Plascore and talk to a salesman. Tell them you want:

4 sheets of 4' x 8' foot Plascore (with resin barrier) 3/4" thick.
The Plascore itself is not expensive but the shipping is roughly equal to the cost of the Plascore. That's the way it is.

You will have to scarf the Plascore pieces together to make some longer than 8' feet and some wider than 4' feet, which is time consuming but not hard.

Raka Resin and Fiberglass

4 gallons resin
1 gallon slow hardener
1 bag microfibers
1 bag colodial silica
1 bag micro balloons
1 roll 6" 9oz fiberglass tape
60 yards fiberglass fabric.

Overall Big Picture for glassing the boat

The layup details for the bottom panels, sides and deck, will be discussed in greater detail later on. This discussion now is a way to make sense of the materials list and to create a preliminary picture of events to come.

Bottom Layup

I used to think a 54" wide bottom meant I had to buy 60" inch wide fabric so I could cover the bottom with large seamless layers. Not so. Any layup can be accomplished with overlapping patches or overlapping rows of fabric. The last time I bought fabric Larry at Raka had a closeout price on some 4oz 38" wide fabric. So I bought a whole roll. Fabric width is somewhat arbitrary. It doesn't matter if it's 30" inches wide or 60" inches wide. If you have it you can make it work.

I used that 4-oz 30" wide fabric in different ways for the OneMan. For the bottom I made two diagonal rows of overlapping fabric oriented at 45 degrees to the long axis of the boat. One row slanted 45 degrees to the right and the other 45 degrees to the left. Each new row of fabric overlapped the previous one by half, so each such row made ended up as two layers thick. Two layers slanted this way and two layers slanted that way ended up as a bottom layout 4 layers of 4oz fabric thick at any given spot. .

Sides Layup

I made the sides of my first prototype OneMan Dayak 12" high above the chine, measuring at the oarlock position. It's a great boat but I new recommend 15" high, primarily as a way to gain more dry storage space below the top deck. The form dimensions given above show a 16" side, so how high you make the sides (how high the vertical distance between deck and bottom) is largely up to you. For the side panels I skipped the diagonal layup and made two layers end to end, with full length strips of fabric, two layers outside and two layers inside.

Deck Layup

For the deck I went back to overlapping rows again, but this time at right angles to the long axis of the boat rather than at diagonals, where each successive layer overlapped the previous layer by half, making the layup two layers of fabric thick inside and out at any given point.

Chine and Deck Fastening with Tape

For fastening the deck to the sides and for reinforcing the chine

So, for fabric call Larry at Raka and tell him you are building a home made fiberglass drift boat and that you need approximately 60 yards of fabric. And that you want to know what his best deals are right now. The above square footage was based on the idea of 4 layers per panel, 2 layers inside and 2 layers outside everywhere except the outside bottom, which gets 3 layers. All of 6oz fabric. You could easily use 4oz fabric and add an additional layer to every surface. Talk to Larry.

Remember this: saving money is not the reason to build your own boat. If your primary motivation is saving money, buy a used plastic or aluminum boat.
Build this boat if you like building things. And if you want a unique hotrod that rows better than any other boat.

Big Picture Sequence of Events from start to finish

1) build AND STRAIGHTEN the plug or form (1/4" construction grade plywood plut 1/2" wafer board)

2) Scarf two sheets of 3/4" Plascore to make a 4x16. Now cut out the side pieces and the two transoms.

3) Scarf up a bottom panel blank.

4) Cover the form with thin 4mil visqueen

5) Attach side pieces and transoms to the form. Glue the edges together

6) Trace out the bottom panel. Cut the bottom panel as marked in the tracing process. Preglass the inside surface only. Attach the the bottom.

7) Glass up the outside

8) Pop the hull off the form. Straighten it up one more time. Glass the inside

9) Scarf up a deck panel.

10) Trace out the deck panel. Cut the deck panel as per traced. Preglass the inside surface only. Attach the bottom panel.

11) Cut a hole for foot well. Make the foot well. Make the foot well. Attach the foot well

12) Mark fastening points for what ever seat mechanism you will use. Fill a few of the honeycomb core cells surrounding any bolt holes or screws.

13) Cut out for any locker lids. Add 3/16" inch shim strips to the edges of the locker lids. I used MiraTech fascia board material, which is a water proof plastic board material. Has little strength but it doesn't swell. And it's only a shim.
Add a rim all the way around the (now shimmed out) lids. Add matching inside rims to the inside of any access hole (you can make flush lids if you are ambitious).

14) Make raised oarlock towers with Plascore scraps and fiberglass. And PVC water pipe for 5/8" inch oarlock pin liners (drill out PVC water pipe with a 5/8" inch twist it 1" PVC? I think so....I'll look it up and fix this later).

15) The rest is hardware details and fiberglass finishing. Autobody work and paint.