Eliminating center thwart om the Gardner 16 semi-dory

[madjack]

Hi everyone,

I have been reading The dory book and am interested in building the 16 foot semi-dory. I know and agree you should stick faithfully to designs. - this being my first build, I am all too aware of this fact-, but I am not getting any younger and hope to use the boat well into my old age. I do not want to be scrambling over too many thwarts as I get up there. This leads to my question. Is there any way to reinforce or stay the sides which would make this feasible? I know this is heresy, so you don't need to remind me.
Thanks for any feedback

[wizbang 13]

Semi Dory...is that a dory with a big transom for an ob?
shoot, I've never NOT modified a boat.
I agree with Terry. Side decks,laminated lower knees, a lower thwart?

[Ben Fuller]

I need to check the semi dory plans, but for most dories the seats are removable, rely on the frames for side stiffness. You might be able to set up the center thwart to be removable. That said, side benches add consideraly to side and and longitudinal stiffness.

[gypsie]

You could laminate up a frame that goes athwartships - aka the Nutshell.
Or a low bulkhead with cut away's to allow movement.

[oldcodger]

Something like this?

P1010096.jpg

It "feels" stronger and stiffer than it needs to be so could be pared down and lower the height of the cross bar but has not been used enough to judge by experience.
Also stiff gunwales help.

[Thorne]

Try it and see, you can always add one later unless you drive the boat so hard it comes apart.

[Ian McColgin]

I built the Chamberlain gunning dory Leeward from Gardner's book. At the time I was smarter than Gardner so I modified: Laminated frames about half the scantlings called for; 1/4" planking rather than 3/8 with similar reduction bottom; like that. And no thwarts. Leeward kept her shape through all because the laminated frames had two (inner and outer) runs of carbon fiber, very stiff, and the laminated inwale/outwales, about 3" wide by 1/2" deep, were very strong.

My being "smarter than Gardner" is a reference to my being sure I did not need a strong back to build on. Nothing makes for more work more than a smart guy short cut.

[Ben Fuller]

Having looked at the plans, I'd run the side benches forward another 10 inches into the space that the center thwart normally lives. You might want to run them all the way to the forward thwart. They are fastened to the seat riser but will need support at the inboard edge, which you csn do with struts going down to the frames. If, after doing this you decide you need more stiffness, you can always put back the center thwart. It can be made removable yet still structural, with dowels and into holes and a snug fit into the center frame.