Food for thought Martin one of the good sides of a Forum is ‘You meet people from all over the world’ but this does have a drawback.
When people give advice; the people giving the advice don’t know the capabilities of the person receiving the advice – and, this was the case when I was giving you advice about your hull build.
If we had known each other personally, I could have assessed/known how good of a builder you are.
This may have altered your thoughts on your build.
When we first discussed diagonal planking; and the materials to use and the procedure to use; I for all my sins have to be excused because I took you as a complete novice. I was expecting the planking to have some unevenness and also to have a certain amount of large gaps – WRONG!!!!! So here we go, this is for anyone else who is interested also.
First of all, think of the material that you are going to be planking with; in your case it was 1/16 planking. This doubled up for the two skins and equates to ⅛ inch thick hull. When we look at this and think about the strength of this actual build – you have produced a very, very strong hull – near enough ‘bullet proof’.
This is because of the makeup of the actual material you have used and also the way you have applied it.
I bet now, if you took the boat, you could literally bounce this across a concrete floor without any damage DON’T TRY THIS THOUGH then you proceeded to coat it with another extremely strong material – woven roven or woven matting – and coated that in resin.
Now, if we can stop there and just think about why we are using the woven roven in the resin; because it is going to increase the strength even more to a hull that doesn’t really need strengthening any more. What we should have done is, just give the hull two or three coats of epoxy resin. Not polyester resin, but, epoxy.
This epoxy would have penetrated the first layer of your hull’s outer layer of plywood planking ONLY to the glue bond of the plywood.
Effectively it would create a good true seal from exterior environments. This would have been all that would have been required on this type of hull.
Sorry my mate, but don’t bother trying to remove what you have already done. Dress it up as per plan; and you are going to have a slightly heavier hull – but, immensely strong!!!!
Now for other builds; there are many way of building hulls with many materials and a lot of these materials, plus workmanship would not stand up alone to the environment that we use them in.
Let us take for instance, a large hull built from balsa wood – which is very practical – a lot of people build this type of hull very successfully using balsa wood. However, one of the drawbacks with this is, if the outer skin is damaged, it absorbs water pretty quickly. Joints will begin to spring with the absorption of water through the damage – if left unattended that is.
To counteract this, what a lot of builders tend to do is give the balsa wood a coating of polyester resin and then, over the top of that, sometimes they will use car body filler to fill any discrepancies in on the hull.
Then, over the top of that, when it has been sanded they will apply either a layer of chopped strand mat and resin, sand it to a smooth finish or, tissue mat and resin. This does two jobs;
a) it gives an effective barrier between the exterior elements and the balsa wood and
b) also slightly increases the strength of the hull build
If we go one stage further and add matting to the inside of the hull, which we should do, this will also protect the hull from water penetration on the inside. It will also add a little more strength to the hull.
In actual fact, this type of hull can be classified as a true composite build – like that which is seen on some real/life sized boats – i.e. pleasure boats/sailing boats etc.
The other type of construction is when we use tougher materials; the more tough the material is, the less exterior protection we have to add – well that is in theory. When we say protection we are referring to either an epoxy or a polyester barrier between our elements and the exterior of the hull.
The other reason we use a polyester/mat/tissue is – if we have had to do a lot of reshaping of the hull – say if we have left a lot of gaps in the planks and we have had a lot of hollows to fill in with car body filler.
When we apply a skin of epoxy or polyester laminate e.g. when I say laminate, I mean mixed with chopped matting or woven roven. This actually bonds all the materials together in one harmonious structure.
Hope this gives you some thought Martin and everyone.