No Name Scull Boat Build......update........ We named her the Double Nickel.........

Great thread! I have been lurking from the beginning, just curious have you come up with a name for it. I will continue to follow along keep up the great work.
 
I'm really, really loving following this thread, mold building and glass boats are completely foreign to me and I love getting to see how it's all done. That design looks great, and I can't wait to see it on the water. A sculling boat is high on my wish list, I'm pretty sure I would have the only scull boat in Utah if I built one!
 
Dale~

Regarding your plastic film - I agree about using cellophane packing tape. Cellophane has long been a standard but I have not found a goods source for it - except for craft/hobby stores. I think sheet cellophane taped down with packing tape would be a good combination.

Polyethylene plastic definitely does NOT work with polyester resin (although fine for epoxy). I learned it the hard way because the plastic puckers and wrinkles from the styrene.

Wax paper can also work for small projects - but it seems to melt from the heat of a hull layup and so loses its value as a barrier. We used it taped with cellophanr on one boat - but it gave us too much anxiety during the "popping off" stage.

Great post - and congratulations on all the progress.

SJS
 
Great thread! I have been lurking from the beginning, just curious have you come up with a name for it. I will continue to follow along keep up the great work.

Chris, No Name yet. You got one for us ?
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Cody,


There is a guy that goes by Toasty on the scull boat forum, I'm pretty sure he is near salt lake.


Dale
 
Dale~

Regarding your plastic film - I agree about using cellophane packing tape. Cellophane has long been a standard but I have not found a goods source for it - except for craft/hobby stores. I think sheet cellophane taped down with packing tape would be a good combination.

Polyethylene plastic definitely does NOT work with polyester resin (although fine for epoxy). I learned it the hard way because the plastic puckers and wrinkles from the styrene.

Wax paper can also work for small projects - but it seems to melt from the heat of a hull layup and so loses its value as a barrier. We used it taped with cellophanr on one boat - but it gave us too much anxiety during the "popping off" stage.

Great post - and congratulations on all the progress.

SJS





Steve, What we found, is that anything that is wide, had a tendency to wrinkle with the complex curves. The carpet sheeting was somewhat stretchy. That avoided some wrinkles. But it has tiny imperfections that caused seeping of the resin. The tape was narrow enough to conform to the complex curves well. We found it in bulk packages at home depot.

Dale
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Now, it’s time to install the transom. First step was to encapsulate the plywood. Almost every Humboldt style boat that I have ever messed with has some rot in the transom. We designed this boat to have the plywood totally encapsulated. And I figured out a way to make a collar to attach the oar boot, without screws penetrating the transom. OLD Leonard came up with a perfect way to attach the leather to the oar hole without using having to remove and replace the screws every time. With these new ideas we won’t have to worry about water seeping into the wood. I’ll go over these ideas later. To encapsulate the plywood we used two layers of 1 1/2 oz. chopped strand mat. After that kicked off, we used a sheet of chopped strand mat between the transom and the rear of the boat. this will act as a gasket between the two, so there are no air pockets, and help bond the two. We made a filet of thickened resin along bottom three sides. Then a couple layers of mat over the filets. We then bored the oar hole. We rounded over the edges. I ground the thickness of the hull down a little around the oar hole, to make room for additional fiberglass cloth, wrapping the inside of the oar hole. That way the transom will be flat, and not have a bump around the oar hole...... More to come..........

 
Good morning, Dale~

I hate to throw a wet blanket on your fine work, but....this is one job where I would use epoxy. Although you certainly did a thorough job encapsulating the wood with the mat, the fundamental risk is that polyester resin is never truly waterproof. This is why factory-built 'glass boats no longer use wood for transoms or stringers or other framing. And why 'glass hulls have gelcoat between the polyester and the sea. Water vapor can/will penetrate the polyester skin and ultimately saturate the enclosed wood enough to enable fungus to flourish. An option here would have been to encapsulate the wood with 2 or 3 coats of epoxy resin. You could then cover with mat and polyester if you thought physical protection was needed. Or, the inside face of the transom could simply be painted or saturated with a wood preservative - to allow any moisture to escape. The edges could be sealed with epoxy.

Another option would be to use PVC "lumber" (like Azek) for small jobs like this.

Having said all that, a dry-sailed boat stored with ample air flow probably minimizes the risks. So, no need to lose sleep - any I was already up anyhow!

All the best,

SJS
 
Frank~

Good thinking!

I've got some in the shop - I use it on boats that'll spend a season afloat.

All the best,

SJS
 
Good morning, Dale~

I hate to throw a wet blanket on your fine work, but....this is one job where I would use epoxy. Although you certainly did a thorough job encapsulating the wood with the mat, the fundamental risk is that polyester resin is never truly waterproof. This is why factory-built 'glass boats no longer use wood for transoms or stringers or other framing. And why 'glass hulls have gelcoat between the polyester and the sea. Water vapor can/will penetrate the polyester skin and ultimately saturate the enclosed wood enough to enable fungus to flourish. An option here would have been to encapsulate the wood with 2 or 3 coats of epoxy resin. You could then cover with mat and polyester if you thought physical protection was needed. Or, the inside face of the transom could simply be painted or saturated with a wood preservative - to allow any moisture to escape. The edges could be sealed with epoxy.

Another option would be to use PVC "lumber" (like Azek) for small jobs like this.

Having said all that, a dry-sailed boat stored with ample air flow probably minimizes the risks. So, no need to lose sleep - any I was already up anyhow!

All the best,

SJS




Yea Steve,

I thought about this. Both our boats live in nice dry garages. With our construction methods, plus all the glass is painted, inside and out, it should out last me.

Dale
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Man, this post is really getting the wheels turning in my head......thanks so much for posting!




Cody,
If you think about it, you could build any small craft with this method.
Dale
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Next step........ Building the boot collar. Most if not all Humboldt style scull boats, use a metal ring, or flange to attach the neoprene boot. This old method is a pain to install. It has screws that penetrate the transom. So I figured out a way to make it a snap, to change an oar boot, with a hose clamp, and a little silicone sealant. To start this off you need a straight sided plastic cylinder. I used a plastic jar. Cut some strips of scrap glass cloth, wet out and wrap around the cylinder. It wants to end up around 1/8” to 3/16”thick. After it cures, cut it to around 1 1/2” tall. It should be around 4 1/2” in diameter. I then held it in place, and checked oar clearance. I ended up installing mine off center. OLD Leonard installed his centered, and had no problems with oar clearance. We then took a very small bead of hot glue and stuck it in place. We used a small filet of thickened resin in and out. Then a couple layers of cloth, in and out. Now to install your boot just apply a small amount of silicone sealant to the inside of the boot, and secure with a stainless steel hose clamp. Ta Da.................



 
Dale~

Great idea - and beautifully executed once again! It's that "attention to detail" that is one of the best parts of boatbuilding - and what separates the good from the great.

And, I just noticed your C on the centerline - gotta have it!

All the best,

SJS
 
Dale~

Great idea - and beautifully executed once again! It's that "attention to detail" that is one of the best parts of boatbuilding - and what separates the good from the great.

And, I just noticed your C on the centerline - gotta have it!

All the best,

SJS




Steve, When I was a kid my folks didn’t have much money. So I didn’t have many toys, but I did have the use of my dads tools. So if I wanted a toy truck, I made one. I also am lucky in that, I had wood shop, and metal shop in junior high. I also was a teachers assistant in wood shop all through high school. Most kids these days see a hammer as a weapon, instead of a tool. Thanks for the kind words, Dale
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Next step, is the motor well. Since I plan on moving the sculling position up a foot. I decided to make a motor well, instead of raising the transom. I want the boat as low as possible. After figuring out the size, and angles. Time to make the mold. I decided to make it out of wood. I made it with a flange around the sides. That way when we do the layup on the deck, it will be bonded to the deck via the flange. I made the mold, then used bondo to fill in any imperfections. After final sanding, I gave it two coats of epoxy. I gave it two coats of pva, then laid it up using the same layup schedule as the hull. After using the boat, I’m super happy with the motor well design. If I ever build another scull boat design I will use the motor well again............ More to come................



 
Time to start the deck mold......there are a few things, that I want to incorporate into the deck design. First thing that I want to eliminate, is the combing. I really don’t care for the shadows that a combing will cast. Most scull boats have an abrupt angle were the combing rises from the deck. This is what the ducks will see coming at them. Also, if the deck is wet, it can reflect the sun, and have bright spots. So my deck will rise up out of the water, with a crowned deck to shed a wave, with no combing. I started off the process, by cutting scrap plywood in segments, to follow the curve of the hull. This will support the mold. I then cut out the cockpit opening out of a 2” sheet of foam. I increased the deck height 1” from my old Lyn Lee. You can see the cut out, for the motor well. The motor well will be recessed down, even with the mold, so it can be bonded in, when we do the layup. I put about a 1” crown in the front of the deck. Once I cut all of the frames, and secured them in place, I glued all the foam in place. I applied 4 layers of blue tape to the edge of the hull, at the joint. This will give a little space between the hull and deck. As I said earlier, I’m going to use a shoe box joint, instead of a flange joint. A flange joint is a weak spot in a Humboldt design. They tend to split open, over time, also if you have to roll the boat on it’s side, it will be way stronger. In a flange joint, it tends to chip the edge, if you do this. Now time to sand and fare, to final shape....... More to come...........

 
Next step....... Time to put a layer of taping mud over the deck. Then sand to the final fare shape. Then a couple coats of oil base gloss paint. We used gloss paint, so the tape will stick. The surface has to be smooth, before the packaging tape will stick. For the deck we used only the tape, and skipped the plastic sheeting. With the tape only, they de molded with zero problems. We sprayed two layers of pva, then used the same layup schedule as the hull. Here again, we could have went lighter. Next time, I would use 3/4 oz. chopped strand mat instead of the 1 1/2 oz. I really like the 7725 modified twill. It drapes very well, over complex curves, like a boat hull. I urge you to give it a try. So both decks are laid up with no problems. More to come...........


 
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