Wood, Plastic, Fiberglass

[Barry]

Does it offer anti fouling due to the nature of either its composition or surface slickness?

 

[sdowney717]

Does it offer anti fouling due to the nature of either its composition or surface slickness?

Unfortunately, no.

barnacles like it a lot, just like most surfaces. But you do get a dry sealed boat.
The planks were originally wooded, and then the seams were cleaned, and I used PL Premium construction adhesive mixed in 30 to40% sawdust.
Forced that into the hot mid summer open seams. Then sanded it smooth and top coated with the polyurethane mix. The plank seams and Sanitred Permaflex was done in 2005

However on the 2014 haulout, I noted the Santred permaflex was not sticking well to the white oak keel, it was not falling off or loose. But it did stick well to the mahogany planks. So as another experiment, I coated with Black PL to a wooded keel, the bow and stern of boat leaving the mid section as is.

So now I go in and out of the water with no need to swell up planks. It has worked very well for me. The hull is stronger than new as the planks are all like one unit, glued together.

 

[Rumars]

The builder of that boat, if you watch his other videos, has used these plastic frames before in wood boat repair. This is not a one off boat.
And the planking aids in aiding stiffness.
Since he has the experience, I dont view this as an experiment.

Repairing and building new are two different things. When you sister a broken frame you are just adding strenght, not removing stiffness. Even if you replace some of the frames completely with plastic, it's not a problem, there is enough stiffness redundancy (carvel boats are strenght limited) in the remaining wooden frames. The advantage for repairing is ease and speed of install.

When building new, there is no advantage. To get the required stiffness you would have to use much deeper frames, cut not bent. Screws cost more then epoxy, plastic costs more then wood, and the speed of framing is not that much greater then steam bending or laminating. Not to mention that it does not really make sense to laminate the skin and mechanically attach the frames.

My point is, if you want to use plastic frames it's fine, but please understand how the given structure works and use them correctly.

 

[sdowney717]

Repairing and building new are two different things. When you sister a broken frame you are just adding strenght, not removing stiffness. Even if you replace some of the frames completely with plastic, it's not a problem, there is enough stiffness redundancy (carvel boats are strenght limited) in the remaining wooden frames. The advantage for repairing is ease and speed of install.

When building new, there is no advantage. To get the required stiffness you would have to use much deeper frames, cut not bent. Screws cost more then epoxy, plastic costs more then wood, and the speed of framing is not that much greater then steam bending or laminating. Not to mention that it does not really make sense to laminate the skin and mechanically attach the frames.

My point is, if you want to use plastic frames it's fine, but please understand how the given structure works and use them correctly.

Think about his planking setup. Double planked, diagonally. Mahogany, edge glued and screwed together. And the double planks sides glued to each other. That planking is going to strengthen the ship a lot is what I think. the mast stays are going to try to pull the hull in like collapse it, and the hull design will be even tighter. I dont see any problems here at all. Plastic frames cant out stretch the planks. The frames are going to be passive, not working against the planks. Plastic that might stretch by itself in the summer sun, is not going to move when fixed in place.

Only think I dont like about plastic frames, is they probably cost a lot more money, than using locust wood etc...Not that I have bought any to know, just my guess, hope I am wrong. Personally I dont like bent wood frames, prefer sawn cut or laminated frames. My experience is the bent wood ones break and cause a lot of problems and effort to repair when they fail.

Boat builders constructed a lot of crappy wood boats over the years. I consider mine one of them, but I improved it from their lousy job. I dont think they intended them to last more than 10 years.

 

[Rumars]

They do not use diagonal planking, all the layers are longitudinal. But the point is they are not using the material properly. Once you laminate the skin (diagonally or not) the frame scantlings can be recalculated. Some of the frames are now superfluous because the skin is stronger, and the rest don't have the required stiffness because of the plastic. All that's keeping the boat shape are the bulkheads and the deck.
The entire build shows many of such inconsecvential decisions. They want the carvel look, but instead of doing a proper double planking they strip the first layer, so the inside does not look carvel. When stripping they bother to progressive bevel the strips, then cover it with a second layer. Laminate the skin, use screws to attach the frames. Plastic is good enough for the frames but the deckbeams are laminated wood. Etc.

I am not against using plastic for the frames as long as it done properly. Simply changing the material and keeping the dimensions only works for the occasional sistering, if you want a new build you have to do the math.

 

[sdowney717]

They do not use diagonal planking, all the layers are longitudinal. But the point is they are not using the material properly. Once you laminate the skin (diagonally or not) the frame scantlings can be recalculated. Some of the frames are now superfluous because the skin is stronger, and the rest don't have the required stiffness because of the plastic. All that's keeping the boat shape are the bulkheads and the deck.
The entire build shows many of such inconsecvential decisions. They want the carvel look, but instead of doing a proper double planking they strip the first layer, so the inside does not look carvel. When stripping they bother to progressive bevel the strips, then cover it with a second layer. Laminate the skin, use screws to attach the frames. Plastic is good enough for the frames but the deckbeams are laminated wood. Etc.

I am not against using plastic for the frames as long as it done properly. Simply changing the material and keeping the dimensions only works for the occasional sistering, if you want a new build you have to do the math.

Did you actually listen to the video?
He said there is an inner plank layer, and a second plank layer will be run at an angle to the inner layer.

 

[Rumars]

Did you actually listen to the video?
He said there is an inner plank layer, and a second plank layer will be run at an angle to the inner layer.

I actually watched the videos, and what he is doing is laying a traditionally spiled planking layer longitudinally over the strip plank. There are places where the seams of the two layers cross at an angle, primarily at the ends, but this is only the result of the spiling and the hull shape, it's not diagonal planking. He is not running the second layer keel to shear, it's still stem to stern.