diagonal planking

LMAO
no Im not going to build it here
thought had crossed my mind but the idea kept going fortunately
although I did start overbuying on wood for the various summer projects
turns out this new mill is pretty generous with the quantities and now I have way more than I ever needed
they loaded up about half again what I ordered no charge
and I over ordered to begin with
now to see how the stuff surfaces out
I start planing it off tomorrow
for as much as I hate surfacing wood I hate how badly a job the mills tend to do so I just broke down and got a Jointer

no worries
Im not building in Colorado
that was a very fleeting thought
cheers
B

oh
and I might have given up on the transoceanic requirement
at this point Im thinkin serious coaster but no real open ocean work
inside passage and northwest west coast Alaska to Portland and the Columbia river area
if I had to pick a nice spot along the coast were the fishing is still good and the land unspoiled
that would be it
it does have some serious waves though
besides there is a nice inlet I can anchor in somewhere up there with my name on it
that and a bar stool in some local pub not to far away

 

? on the cutts what size cable do you use?

thanks patrick

 

I'd like to double plank with the seams staggered and the planks parallel to one another. A bit like making batten seams with the battens as large as the planks. Dolphinite or sim would seem reasonable between the planks. With planks on top of one another how should the 1st screws be located so as to not interfere with the screws of the 2nd planks. On any double plank would wood preservative or anti-fouling paint be worth the trouble?

Easy Rider

 

anti-fouling is always worth the trouble. On the screws its been a long time and someone with more experience than I should chime in but I seem to remember both staggering the screw pattern and also sometimes removing the ones that were going to be in the way. Depends of the situation.

best of luck
B

 

STLNOBLE, the Cutts method is a proprietary building technique and you'll need to contact the "old man" in Maryland.

Easy Rider, you describing a known method often called Ashcroft planking. It's one of my favorites to work with, because it's the quickest way to mold a hull. Typically, you mark the second layer for first layer fasteners, as you lay the planks. Dolfinte or other sealant between the layers would require the fasteners to bear all the loading, which takes the planking out of the loop to a large degree.

The ideal method is not to seal the two layers, but bond them tightly, so they act more like plywood. This way the planking skin becomes a monocoque shell, not a lightly assembled bunch of planks, riding on frames. If you glue them, you don't need frames, but if you just use sealant, you do need frames, lots of them.

Most round bilge build methods can be converted to Ashcroft, but it does require an experienced designer or NA to perform the conversion. I make conversions like this a few times a year, it's a fairly common request.

If it's a boat that will spend it's life on a trailer, then you don't need anti fouling paint. In fact, I have an Ashcroft built runabout I built over 20 years ago. It's never had a drop of paint of any kind, anywhere on the boat and though it will get a varnish job this winter, it's no worse for wear. It's a trailer boat and lives indoors when not in use.

 

EasyRider your idea brings back memories of my Dad's observations. I had an old Cedar boat which I loved. I had the same I dea you mention. I'll just put another layer of boards over the seams of my big 22' Cedar Skiff.

Dad said: "That's Hill billy Siding!" what we'd call board and batton of it were vertical on your house down in Southern MO. But it works very well in houses.

On my Cedar boat, I had 3/4" Cedar boards about 6" wide.
Cotton/Oakum and caulk in between each.
That was one meeezzerrrrrbulll job! I did both sides, the full lenght of that boat by myself.
I had a mallet and three ripping tools, four Packing tools and the energy of youth.

Up in Thorne Bay you should be able to come up with enough Torrredos to eat a Cedar boat in a years time.
What kind of wood would you use? If you used Yellow Cedar, how would you keep the Torredos out?

 

An Ashcroft build doesn't need caulked seams, just good contact between the inner and outer layers.

 

cutts patent

thanks PAR

Some one told me the the cutts Patent time ran out so it was legal to use it

patrick

 

resorcinol glue. ,, and good quality ply (Thames ply) with Monel staples (dont have to be pulled) does a fine job for a really lightweight stiff hull.

Interior bulkheads and simple stringers define the hull , little waste , little weight.

Very low labor skills required to diagonally ply , a 6x30 table sander to take care of edge fitting is about it , roofers hammer stapler is enough to set the staples , no worries about oil contamination from an air tool.

FF

 

STLNOBLE, I've seen the Cutts method up close and I see absolutely no advantage to this system at all. I know the patent was coming up, but I'm not sure if it's finally spent. If you want to pull the patent and find out, that's great, but frankly, I don't see the need. It's a difficult, costly technique and you can have hulls just as strong without all the rabbets and high tech cordage.

 

Hey Thud,
Whats zis about Torredos? I've heard of them but not up here. We have both yellow and red cedar and several mills to cut to whatever.
Easy Rider

 

Yes I can relate to the high strength achieved by fastening or gluing all the planks together but how on earth would one repair the latter. One of the remaining virtues of building a wood boat is that you can take it apart. If one used glue, and the glue held I would think the planks would break apart with expansion and contraction. Staying together with 6" wide planks? .. hard to belive.
I was thinking in terms of a modified flat bottomed Atkin cruiser rendered as an open skiff and cross planked on the bottom. Absolutely everything in Yellow Cedar except the outer topside planks in Red Cedar (just because it's so beautiful varnished). I hope the Yellow Cedar would have the fastener holding power for frames ect. The boat would be on a trailer and I meant for the anti-fouling paint to go between the planks. The Bay here is about 6 miles long and 1/2 to 3/4 mi wide. It's alive in the summer with aluminum skiffs, 25' aluminum boats and a few aluminum barge like catamarans. Ugly boats all and I even have a skiff. Thanks PAR,Boston and FF for your input.

Easy Rider

 

Teredo navalis
is a clam, known as "ship worm" it eats a wooden boat for breakfast when there are enough of them around.

A epoxy coated and properly painted hull is safe. (they do´nt know there is wood under the plastic crap)

Regards
Richard

 

If you build using traditional methods (plank over frames) then you are working an assembly of pieces, which usually requires little glue and lots of caulk. If you use modern methods, you're building a monocoque structure, with lots of glue and probably no caulk. There is a huge engineering difference between the two and as a rule, they can't be intermixed successfully (at least it's very difficult).

Double planking can be done both ways. If a traditional method, the planks are narrow and sometimes caulked on the outer layer. This limits movement (big pieces have big movements with moisture gain) so it doesn't rip itself apart.

If it's a modern build you can use huge planks, like full sheets of plywood. This is because the planking is stabilized and not going to move, the moisture content remains constant.

Ashcroft method (which is veneer molding, not double planking) if traditional uses 7 - 9 pound shellac between the layers which is a very effective glue. Modern methods use regular adhesives.

A neat trick old timers use to defeat the Teredo and other water born beasties, is to simply nail a nice fresh hunk of balsa at the LWL, so it's well exposed. No paint, nothing to interfere with their dinner. They'll eat it first before chowing down on your bottom planks. When it gets about half eaten, replace it with a new "entree" and they'll leave you boat alone. A 12" 4x4 hunk is common, nailed to the transom at the LWL.

 

....PAR...sacrificialy docking plank is what we use here in Australia, does exactly the same thing and serves both purposes.