Rusted fuel tanks

I had been hoping the fuel tanks were still serviceable, I knew the tops were badly rusted but not no holes appeared when I scraped the loose rust off.

There was a lot of rust on top of the tanks I spent about an hour scraping with a very large crow bar and vacuuming the loose rust.

However when I removed the partition surrounding the starboard tank I found it was leaking at the bottom.Notice the stained black area, it has been leaking for some time. I actually got lucky here, when I started to cut the tank the hole opened up much bigger.
So it was time to cut the tank out. I tried all the various cutting tools, 3" and 4" grinder with carbide cutting wheels, jig saw with metal cutting blade, but the fastest turned out to be the acetylene cutting torch....

I did cut the first section off the front of the tank with the grinders, so I could clean the last of the diesel out.
The white you see in this picture is paper towels buried in the much that was in the tank. Doesn't look like the tank was EVER cleaned. Which is a real shame the sides and most of the bottom of the tank were just fine. It was just in a few spots in the bottom 1/3rd of the bottom panel that had rusted.

I don't know of any way to reliably repair those spots. There was a layer of rust in the muck. The real shame is that there was a drain plug at the lowest corner of the tank. All this could have been prevented by just draining  the water out every 6 months or so.

So we decided that while we had the boat all torn apart we should go ahead and replace the tanks.

I started with the metal cutting angle grinder disks. It was very slow frustrating work, the 3" cut much slower but the disk lasted much longer than the 4" disk. After cutting 1/3rd of the front side off I cleaned that section out and went to it with the torch. Only had to put a few fires out during the process. The worst was when I cut the baffle to the next section out. I tried unsuccessfully to wash the dirt out with the spray nozzle on the hose, but there was still gunk left that caught fire. But the hose was handy and successful at putting the fires out.

It took about  2 days to cut the whole thing up. First the front then the sides and baffles. Then I could bend the top down enough to cut it into section. That left the bottom and back side(up against the hull). I ended up putting pieces of steel I had cut out under the bottom to protect the hull while I cut the bottom up. I had the garden hose right at hand the whole time. I also made sure to keep the areas of the hull near the work wet. It all worked out, no burns to the fiberglass.

Tank removed, pressure washed and ready to start building the new tank. We have decided to put 4 tanks in, 2 to each side. Yes it will cost a little more and be less convenient when filling, but I like splitting the tanks up so each does not carry so much fuel. I estimate that the old tanks held around 400 gallons  each. I am planning to carry about 600 gallons in 4 tanks. That will give me more room for other equipment. At 4 miles per gallon that is a cruising range of 2400 miles. We are not planning on crossing the pacific!!

Back to the blog..

Lost touch with the blog during the holidays. But I am back...for now. Can't say I have ever been much of a writer.

I finished glassing all water tank tops on and started  working in the engine room. I was moving towards building the hull sides up and sun deck. However in the process I had to remove an existing access into the engine room from the aft cabin. Cutting it out created a nice opening into the engine room. So I decided that I should get the work I needed to do in there out of the way before closing up the hole.
Funny how one thing leads to another. I ended up removing everything except the engine and the generator from the engine room. I must say there was an interesting collection of various kinds and sizes of hosing and bits of wiring. It's all gone now so I can get a clean start when I go to reinstall the equipment. I also tore out the old walls they had built around the fuel tanks as well as the ceiling along with the 35 year old loose fiberglass insulation they had installed between the joists. But I have finally gotten the "old" boat smell out. Turns out that the acoustical ceiling tiles that had lined the bulkheads and ceiling with had absorbed all the oily water smell.
When I removed the wall from around the starboard tank I discovered that it was leaking...More on that next post.

For now here are some pics of the tank tops.

Here is the aft end of the Port tank and

the aft end of the Starboard tank. The white you see is epoxy paint on the top in the area where I was not going to do any more glass work. When I have finished glassing in the bulkheads and flor structure I will paint the whole area with white epoxy.

Here is the finished upper tank that rises though the cabin sole under the bunk. You can see the two clean-out ports bolted in place. Every compartment in each tank had a clean-out port.

Here is a close-up of one side of the top. All tops were glassed on with 3 layers of biax tape.

Here is picture of the aft end of the port tank. This was before I learned that the starboard tank leaked. I beefed up the glass work holding the tank in place.

I also beefed up the bulkhead  connection. It looks like they had used 2 layer of mat to tab the bulkheads in place. Not really enough, so I added 3 layers of biax tape over what they had done. The hole you see in the bulkhead is where the exhaust hose entered the aft cabin. It is about 8 inches lower that where it exits the hull, meaning that the whole hose would fill with water when the engine was running. Proper installation says that the exhaust hose shall have a continuous drop from the riser pipe coming out of the water lift muffler to the where it exists the hull.

Here is a view of the start of the mold for raiing the hull sides to firm the aft cabin. They are 3/4" Ply covered one side with Formica. They are clamped onto the out side of the hull with a 10 degree tumble home. There is a 4" wide piece at the top to form an angle to attach the deck to. More on that later.