80 ft wood houseboat flat hull needs shell

i have an 80x20 foot rectangular houseboat with a flat wooden hull that is seriously rotting. the boat was built in 1929 (it's old). for about 50 of those years it has been in the water year round. the boat sits at a dock in the fall winter and most of the spring, and in the summer it is taken out to a mooring. over the years the wood has been warped from the anchor pulling down one end and batteries at the other ( this was my father's doing- i have fixed that, and the warping has stopped but it is still curved). therefore there is only one expensive way to lift the boat out of the water. so maintainence on the hull is extremely limited.
we have already wrapped the hull in a large sheet of firestone rubber which has done well for 3 years but we recently found at least 5 sufficient rips.

so we need a new hull/ or casing for our existing hull.
here are our limitations/requirements
-we are in brackish water (material cannot deteriorate in any type of water)
-we are limited in travel, we are located just north of the bay bridge in the chesapeake bay in maryland. we need a location on the east coast.
-it needs to last at least 50 years with MINIMAL maintainence
-we cannot pull out of the water more than once in 5 to 10 years.

any ideas on
-choice of material/hull
-company to contact
-location

please help

 

Is the wood individual planks or plywood?

Getting rid of all the rotten bits and gluing 20mm marine ply over the good bits with epoxy, and doing an epoxy and fibreglass coat over all, springs to mind.

Any half assed boat builder could do that for you.

 

its individual planks, and atleast 10 inches thick
and do you know how long fiberglass and epoxy last?

 

Epoxy/Fibreglass in the environments you specify should last another 150 years or more.

10 inches thick sounds amazingly huuuuuge! If that is the case though, maybe by the time you take out the rotten bits, you will have large voids, but the whole things should still all hang together without a lot of bracing.

Many of the voids will need re-filling, either with new timber or an epoxy/sawdust misture for smaller ones.

The "black hat" in me would expect the whole hull to be so far gone that it would be cheaper to build a new one in ply and epoxy. It might be possible to tear off the old planking alltogether, and then rebuild, and re-plank the frames.

What sort of plank fastenings are used? If they are steel wire like the barges I have worked on, you will have major issues. Copper roves are easiest to deal with. With that thickness, they probably used steel bolts, which will have rusted out and cant be removed easily, and will wreck any kind of power tools.

You have to hope for the best, but be prepared to pay for the worst scenario.

Oh - do you know what sort of timber it is as well? With planks that size, you may at least have a valuable source of well seasoned wood to sell or re-use.

 

Without photos it's hard to know.
But....what about building a new Hull bottom.
Then.....raising the house, replace the old hull at the joint of the Hull and the house with a 'Pony-wall'...
Then....set the House/pony-wall down onto the new hull.

Or build a new Hull bottom of steel or even Fiberglass.

Whatever you do, you MUST get all that old rotted wet wood out from under the house.

You may not know it, but Wood rot's on purpose. It's mother nature's way of keeping the dirt in the world visible. Without wood rot the earth would be covered by hundreds of feet of old trees etc.
So to do a good job of rotting wood away, you need an enclosed, warm space and some moisture. That's why Boat people know more about wood rot than almost anybody else.

Because this thing is so huge, your not going to be able to do the work and keep it all dry at the same time, so plan on being able to pump the bilges and keep them aired (as in breezy) forever.

Thats gonna be a lot of Wood. You'll need to have that all drawn up and a construction sequence all laid out before you start.
Somehwere I read that White Oak is the right wood for Ship building because of Rot resistance. You can find all that on the internet though.
Also, Cypress is still available in large long length's.

I ran onto some guys who made a living by locating and raising Cypress that had been long sunk in the Creeks and Bayou's of Louisiana.
All down in the Southeast U.S. there are Huge Oak's ripped up and strewn about by the Hurricanes.
You might try contacting some of the small logging companies in Louisiana, Mississippi, Georgia, Florida and Texas about getting some timbers made of those Oaks already on the ground.
You should be able to get all you need on one Semi-load.