Keith Poe wrote:[
I think the Douglas fir will be fine i build with it all the time it holds up great to building codes and attached to steel beams etc.
if it does start to sink in i can always easily add a longer plate.
.....replace at any time and they are inexpensive.
..... wanted to be able to remove them with a few bolts.
..... cost about a buck i can easily make new ones in minutes if needed.
I'll see how well everything performs and if she requires more strength or durability I'll be all over it.
.....i really like being able to remove the decking and framing with a few screws.
I believe with the supports on the tank it will be strong and if it's not i will add the stringer supports up to the 2x12 from the stringers on the sides of the tank but do not believe it will be necessary.
The flat 2x12 should offer a lot of support to the diamond plate keeping the thickness 3/16 light weight and coast down.
As it is the space between the 2x12 is only 12".
Interesting... So your desired characteristics in your major below deck structural systems are that they are inexpensive and easily replaceable? I have never seen anyone intentionally seek out these traits for their materials used in structural components in a boat rebuild.
I tend to go the opposite route and spend 3 times as long on the initial install to properly encapsulate any and all bare wood with several layers of laminate complete with radius tops, and thickened resin fillets on the bed before laying the glass. Once I do the work, I want to be done with it... not a never ending project.
Douglas Fir, while being naturally rot resistant, sure does like to rot. I can't begin to tell you how much rotted dougie fir I've
replaced & epoxy patched in the last year alone, in both architechtual and marine applications. Tongue and groove ceilings, doors, handrails, transoms, soffits, bulkheads, soles, etc, etc. It can only take so much fresh water exposure and it's black mush... But if you're planning on treating your structural components as disposable and making it so you can easily remove and replace, well, ok then.
The cockpit deck supports... If you like the aspect that they're removable with a few screws, and plan on doing so to access the various components below, keep in mind that by the second or third time you remove and rescrew the fasteners into the fir, the fir is not going to hold the screws very well any more. You can shoot a little resin in the holes to hold better, but thats pretty limited and will give up the ghost as well, before too long.
Your 2 x 12's could give a lot better support if you ripped them into 2 x 6's, and then reconfigured them so they were oriented vertically - i.e.: 6"tall by 2" wide. That 12" width aint doing anything for you.
Utilizing the fuel tank for a support... come on man. What if it ruptures your tank in heavy seas when a swell comes over your transom because of your set-up- then you've got a swamped vessel, leaking fuel, and if crash valves are your answer- what if you get enough seawater in the fuel to get past the racors and it ingests into the cummins?
For how you propose to use the boat, in the extreme sea conditions, with the inherently risky aspect of the sea anchor off the transom to tempt the sea into your cockpit, etc... I would think you'd want her to be overbuilt to the maximum, with a completely watertight cockpit sole.
I may be off in my thought process, you may not be concerned with either. But as it is now, she exhibits neither aspect...