The Amador is a classic twin screw wooden river tug about 70' LOA, 19' of beam, and a 6' draft. It was built in 1951 at Broderick, CA, just across the river Sacramento. It was originally powered with a pair of Cleveland 8-268A diesel engines, which had been removed from a WWII minesweeper. Some other parts of the minesweeper were used in the construction as well, such as the beautiful wooden doors that grace her interior and the aluminum portholes in her galley.
When I purchased the boat, in Petaluma CA, it was in pretty tough shape. One of the doors to the galley was missing. Every time it rained there was a cascade of water that ran down the walls and though the decks. Not to mention the steady flow of water coming in from the bottom. The boat had not been out of the water in 12 years. This is a long period for a wooden boat to go without the aid of antifouling paint.
Step 1: Haul the Boat Out
A haulout is not strictly necessary to convert a tug. But its a good and expensive idea, expect to spend between 10 and 50k depending on the size and condition of your boat. Over the years I saved quite a bit of money by doing the work myself. The Amador is heavily built so the (considerable) toredo worm and crab damage that occurred over the years was easy to fix. For the worm hole use a propane torch, point it into the worm hole and heat until the worm is dead, a minute or so usually does it. then fill the hole with vinyl concrete patcher, available at your local hardware store. The crabs usually eat away at the wood around the water line you can use the vinyl concrete patch here as well, but on the larger holes prime them with 2 part marine epoxy and while the epoxy is still wet, slather the patch mixture in.
Step 2: Install the Engines
What fun is a boat without a sail or engine? Again this is not a necessary step. But its the path I chose. My tug came without engines so I scoured the waterfront and found 2 Detroit diesel 6-71 engines and reverse gear. Using a lathe I made some adapter plates to mate them up to the existing propeller shafts. I jacked, pulled and pried the engines into position and mounted them using orange chocking compound.
Step 3: Pre Considerations
You may want to consult with a naval architect before starting on any kind of construction just to be sure your vessel can handle the additional top-hamper (weight above the deck) as you don't want to be standing on the side of the pilot house during a strong wind. The Amador was originally drawn up on the back of a napkin so I skipped this step. The Amador had a fairly clear space behind the deck house so all I had to do was cut away the engine room casing and stack (part of which I planed to use later) and some other odds and ends. these parts comprised of steel so they were easily cut away with a gas ax (cutting torch). You may need a gas free certificate before you start cutting depending on your local. I ruined some clothes by cleaning out the toxic flammable muck that filled the bilges.
Step 4: Build the Deckhouse
I started by bolting 2x4 Douglass fir sill plates to the deck and then used fairly standard 2x4 framing for the rest of the deckhouse. the roof consisted of 4x6 Douglass fir beams 16 inches on center, then covered with 1x4 T&G with fiberglass on top. We covered the exterior walls with #16 felt and used a combination of exterior plywood covered with Airbol/yellowjacket and wainscoting consisting of 1x6 redwood T&G. My father being the crafty craftsman that he is, built all the windows and doors from air dried redwood.
Step 5: Other Considerations
At the time of the deckhouse build we also cleaned up and painted the focsle also we cut down one of the fuel tanks to double the size of the focsle. we then added a spiral staircase to replace the rickety old ladder.
R-13 fiberglass insulation was used where posable .
For Hot water we installed a propane instant water heater.
For heat, a wood burning stove was added to the main deckhouse the flue runs up the stack.
All galvanized domestic water pipe was removed and replaced with 3/4" bronze pipe (Salvaged from the condenser on the steam ferry Berkeley)
A holding tank was added for sewage. The bathroom is forward on the main deck.
We used pre fab oak cabinets for the kitchen.
Later we extended the pilothouse aft more than doubling the size.