first time builder questions...

[ndpoole]

Hello all
I am building a 17' dion dory using white oak (frames/transom/ stem), and yellow cedar (planking/bottom). I have not yet chosen type of wood for gunwale caps and thwarts. I am building at my cabin at 70 mile BC. I am frequently out of internet access and am using dial-up so i must ask questions in a bundle...sorry.

Firstly, I plan to sail this dory more(mostly on lakes but hope not to restrict myself to closed water) so i was considering installing sailing seats from stern bench to thwart 2. The beam is 4'6 and am wondering if this type of modification for a boat like this is permissible and practical.

Second, the plans call for a white oak false bottom of 5/8" but am wondering if i could use marine ply. would this affect performance given a lighter weight?

probably crude questions, but are popping up nonetheless. at the moment, I am fairing for planking and there is enough uncertainty to keep me on my toes and nervous.

Any feedback would be helpful. Thanks

[paladin]

I am not familiar with the term "false bottom" used in marine context. In another world it is a temporary structure used to seal a caisson in a dam. So if I use it in that context to mean possible a watertight door or bottom somewhere in the boat, Plywood should work....however........where solid wood gets wet and seals and then dries out, the plywood will not suffer as well. Structerally it may be most sound and practical. In that respect, I would very carefully seal the sides and edges with epoxy, and even go so far as to coat all sides with a very thin layer of fiberglass and epoxy.
However...I could be totally wrong in my interpretation of the problem.
Best of luck.

[Candyfloss]

A false floor in a sailing dinghy implies a buoyancy compartment so that water in the boat flows out thru holes in the transom. Normally ply would be used for this purpose, but by "normal", I mean a ply boat, not a planked one. I am concerned about the stresses such a rigid structure would impose on a relatively flexible hull. Being a ply fan myself, I would say go for it, but wiser council may prevail.

And, welcome to the Forum.

[Thorne]

False bottom is a perfectly correct term, used by Gardner and others.

Here is the false, or sacrificial bottom on my dory skiff, made from lumberyard doug fir painted with red lead paint and bedded in Dolpinite. It goes below the actual bottom planks to protect them from impact and abrasion, and can easily be replaced.
http://www.luckhardt.com/bottom-planks2.jpg


http://www.luckhardt.com/bottom-planks3.jpg


My boat was built with a ply false bottom but it quickly rotted and caused some rot in the solid fir bottom planks. So I recommend using solid wood for the false bottom on a solid wood boat.
http://www.luckhardt.com/dory1.html
http://www.luckhardt.com/falseplybottom.jpg


To answer your questions, yes running thwarts/benches fore and aft from the rear to center thwart is fairly common for sail and oar boats. You can also make the rear seat - called "sternsheets" - in a curved shape so it provides both rear seating and side seats. My dory skiff is set up that way.

But dories being as tender as they are under sail, you'll often sail the boat from the floorboards, and the curved part of the sternsheets makes a comfy backrest if you have a passenger to balance the weight forward. But if you are sailing solo you often need your weight further forward, so I built this removable backrest to let me sit closer to the center of the boat -

http://www.luckhardt.com/backrest1.jpg

http://www.luckhardt.com/elk_mesailingweb.jpg

I'd consider using Doug Fir for the gunwale caps and thwarts, as it is lighter than the white oak, stronger and more impact-resistant than the cedar, and fairly cheap in your area. My gunwales and thwarts are DF and it works out very well.

[Candyfloss]

Oh. That sort of a false bottom. My brain is locked into racing dinghys. Please ignore my previous.

[ndpoole]

Thanks all for the posts. Thorne- thank you for the insight into the false bottom, seats, and wood-of-choice for the gwale caps and thwarts;l did not think of doug fir- a fine looking wood when finished aswell. Is your deck and bowsprit doug fir aswell?
I am especially glad that you replied because i have another question that i was hesitant to put in the first post: i saw a picture of your boat some months ago and loved the look of the deck and bowsprit. I am thinking of doing the exact same on mine... what is the purpose of the bowsprit?... besides looking awesome that is
Thanks again

[Thorne]

The bowsprit is not proper or correct for dories, and if you must add one, it should be of the thinner plank variety (like the SF Pelican bowsprits) to avoid adding excess weight. The bowsprit and all other spars are DF. Everything on the boat is Doug Fir or White Oak, except the new centerboard which is Meranti marine ply.

I had to add a bowsprit because I messed up the placement of the centerboard and mast. Unwilling to tear out the forward thwart for the old-style 'humpback' CB case, I lengthed & thinned the CB profile and moved the mast forward perhaps 8".
http://www.luckhardt.com/cb-design1.jpg

These combined were enough to make the boat suffer from extreme weather helm when the winds picked up -- it would round up and go into irons in strong gusts. Even placing a jib on the stem wasn't enough, so I had to move it out on a bowsprit to balance the helm.

No deck on my dory, but some Swampscot dories have lovely ones, including this one built by Forumite Elad from the Mendocino area -

http://www.luckhardt.com/dale-doryST09.jpg

http://www.luckhardt.com/dale-dory2ST09.jpg

[wizbang 13]

Seein' as how you are usin' a fine wood like Alaska Yello for plankin', too bad ,in 25 or 30 years the oak will go ka-put. Please see about framing the boat with Alaska yello.( for your great grand kids)