New timber - how big should gaps be ?

[Dave-Fethiye]

I have had to replace some of the pine hull planks because they were a bit soft. I got some timber cut and machined to the same size as the boards I pulled off.

I am placing them on - see the photos - but the gaps seem to be rather wide

I will need to use cotton caulk, but is 1/8 - 1/4" too much of a gap to caulk ? Should I get some slightly wider planks or will these ones swell up sufficiently when in the water ?

Would really like some help on this as I have to decide what to do within a day or two !

Thanks
Dave

[Steve Rust]

Dave
I think that your interest in getting the boat in the water is getting ahead of the learning curve on how to do it properly. First of all knots of that size are not acceptable for hull planking and there are what appear to be cracks in two of the planks. Also three of the planks all butt on the same frame. The plank at the turn of the bilge will probably have to be hollowed out on the back(inside) so that it beds firmly against the frame. The others may be okay as the hull is fairly flat there. The planks also need to be beveled on one edge to accept the caulking and seam compound. The bevel depth should be 2/3rds-3/4 the planking thickness and 3/32-1/8" wide. The planks should fit fairly tight on the inside 1/3rd-1/4 of the planking thickness. This is to hold the caulking in place. Without it you will just pound the cotton thru the boat. There is much more to it , I am just covering the basics here as to not give you information overload. Now add the fact that the hull is all dried out with gapping seams. I wonder if the hull needs to be soaked a bit to try and bring things back to where they should be before attempting to fit new planks. My best advice would be to do some serious research before proceeding or hire a boatbuilder you feel comfortable with and offer to be his helper and learn from a professional. It does not look like that difficult a job for someone who is familar and skilled in the craft. I am not trying to rip on you but you need to slow down a bit and do some research.

[Tropic Cat]

Dave,
I posted the link to the wood boat building / repair manual in the other thread you started.

I think Steve has pretty much covered the rest.

Rick in Florida

[Steve Rust]

A little added information. In the shorter lenghts you need for planking it should not be too hard to find some acceptable stock. The way mills cut lumber for the construction market produces fewer planking quality boards but does give them more board feet for the less decerning construction market. When I go to the local builders supply to pick out western red cedar for the decks I build(house decks, not boat), I fell lucky if I find 5 good planking quality boards for every 100 I look thru. I keep these for myself. Look for quarter sawn boards with the growth rings perpindicular to the face of the board (when viewed from the end) with little or no grain runout the lenght of the board. Very small tight knots are okay but in the shorter lenghts you should be able to find some clear stuff. It may be a hassle to look thru a whole stack of lumber but I do it all the time and look on it as treasure hunting. When I see a high quality board I buy it whether I need it or not at the time.

[Dave-Fethiye]

Thanks Steve for the detail you have gone into.
Although it looks like a complete disaster - it won't be. If I hadn't done this yesterday - I wouldn't be learning how to do it right!

Looks like I have to change the wood. The timber merchant did offer me ceder but I thought it best if I stick to the same type of wood that the boat is made out of.

So, I'll get some more wood. And it will have to be wider, with no knots etc.

With regard to the placing. In my photo, the 3rd plank from the left, if that one is made longer - down past the length of the others (will be about 1.5m long), would be the correct placement ?

Thanks again,
Hopefully I'll get there.
Dave

[Steve Rust]

Dave
It has been many years since I had a wood boat so it is taking awhile to jog my memory so some advice may come randomly. I don't know how lumber is processed in Turkey but here much of what is used in the construction industry is kiln dried (using heat to speed up the drying process) and is to dry to be used as planking. Much of this wood is poor quality so it is a moot point anyway with the exception of western red cedar which is readily available green with a high moisture content. This cedar is an excellent planking lumber and certain types of pine are also commonly used. There are differant types of pine and cedar and not all are acceptable and they also differ in differant parts of the world so I can't advise on what's best for you to use. Using the same as what the current planking is probably best. Most boat builders either mill their own stock or work with a mill. This wood is cut green and air dried out of direct sunlight to a certain moisture content and then it is ready to use. Kiln drying makes the wood to dry and it will never be acceptable as planking stock. It would seem to make sense to me to use lumber that is not to dry for the replacement planks and make them fit tight. Hopefully the rest of the planking will swell back to it's original shape and the new will swell just enough to tighten up the new tighter fitting seams.
The caulking bevel is only on one edge of the plank and this edge fits against the straight edge on it's neighboring plank. This bevel changes along the plank lenght depending on the curve of the frames and twist in the plank. With flat runs of planking this change may be little to none. Determining bevels is to much to explain here so a good book with diagrams would be the best way to learn the process.
I think that would better if you lenghtened that one plank. One thing to think about is how much is left of the original plank after you have cut off the bad area? If after cutting off the bad area and a majority of the plank is gone it may be best to replace the whole plank rather than have a bunch of short planks. If the planks are fairly long then it is to much work to replace them entirely.