cape dory 36 fuel tank

[stephen bowen]

Anyone out there know if cd 36 hull 94 1983 ? would have a 43 gallon fuel tank as specified in the owners manual or a 53 gallon tank? The tank is aluminum and is mounted in the keel. Also does anyone have dimensions of the tank and a recommended fabricator? surprise in the bilge! thanks Stephen s/v Namaste

[Russell]

My 1984 CD36 has a 50ish gallon tank, I imagine yours would be the same. As I understand it Florida Tanks made the original tanks, http://www.floridamarinetanks.com/ I would contact them, they likely still have the dimensions on file.

[stephen bowen]

Just removed all fuel from my old tank..seems that the capacity is 43 gallons per the manual. Interestingly, Florida tank identified this tank based on the model number which is still on a sticker on the top of the tank as a 53 gallon tank(Model # 53 cd 53). I am confused about that difference, but am sure it only holds 43 gallons. Next step is to block off all outlets and pressurize to make sure it is indeed leaking from the tank itself and not the various fittings and or hoses etc. Any input on this would be much appreciated but it looks like removing the cabin sole is going to be the next project. Unfortunately, having relocated my 2 8d batteries under the seat in back of the galley sink complicates sole removal a little but the redistribution of weight seems worth it. Stephen s/v Namaste

[Russell]

Let us know how it all goes. I have been lucky with my fuel tank so far, but I feel like I am on borrowed time, it leaking is one of my bigger fears. When I replaced my cabin sole though I made it easy to remove without destruction, in preparation for when that day does come.

[stephen bowen]

Well, it seems that the leaking fuel was due to a leaking hose instead of the fuel tank. After revising my test equipment the empty tank held 3 psi for 6 hours and 2.5 overnight when it dropped due to lower ambient air temps, I believe...anyway I am replacing all fuel lines with exception of the fuel fill line which was part of the pressure test. I must have overfilled the tank and perhaps when temperatures rose somehow the fuel leaked out. It is still somewhat of a mystery since the fuel should have simply flowed out of the vent???

[Russell]

Well, it seems that the leaking fuel was due to a leaking hose instead of the fuel tank. After revising my test equipment the empty tank held 3 psi for 6 hours and 2.5 overnight when it dropped due to lower ambient air temps, I believe...anyway I am replacing all fuel lines with exception of the fuel fill line which was part of the pressure test. I must have overfilled the tank and perhaps when temperatures rose somehow the fuel leaked out. It is still somewhat of a mystery since the fuel should have simply flowed out of the vent???

Well, the vent is higher then anything else, so if there is a leak in any other line it will leak out of that before it goes out of the vent.

Glad to hear it wasnt the tank, that would not have been a fun (or cheap) job.

[mashenden]

... Unfortunately, having relocated my 2 8d batteries under the seat in back of the galley sink complicates sole removal a little but the redistribution of weight seems worth it. Stephen s/v Namaste

Stephen, I am interested in knowing a bit more about your DC layout. I'm considering relocating the house bank (2 6vs) so your comment caught my eye. Sorry for 101 questions, but your input would be greatly appreciated...

• Are the house batteries under the sink or under the seat forward of the sink?
• Any concerns with venting?
• Is your starting battery still in the port cockpit locker?
• Where is your battery switch located?
• How did you route the cables from the house batteries to the electrical panel? It seems very congested going to the engine compartment then to the starboard side to get to the panel.

[stephen bowen]

Well first let me say I wanted to move weight toward the center of the boat, and keep it to port and low in the boat to balance the starboard water tanks. They were mounted in the port cockpit locker... The batteries are 2( 8 d 12 volt agms)so no major concerns about venting. they are under the seat, but the locker had to be modified to allow the batteries to fit. this was done by pushing the back wall of the seat locker back into the storage space to port. this mod allowed the batteries to fit as well as some monitoring and fusing equipment against the center most locker wall. the starting battery is mounted in a custom box under the companionway steps as well as the starting battery switch. the main house switch is mounted under the electrical panel (original location I believe). routing cables was not easy but can be done. The entire system is fused with 400 amp main fuses and descending fuses downstream. 6 volt batteries are taller than my agms I think, and may not fit under the seat.

[John Foster]

Stephen, could you describe your pressure test setup? I have a CD36, 1984, and suspect the fuel tank. I was planning to disconnect the vent line and pressurize via that fitting. Can you leave everything else connected? What kind of pressure gauge did you use and where did you get it? Did you pressurize with a manual tire pump or a compressor?

[stephen bowen]

Using hardware store fittings I plumbed the air pressure guage into the tapping in the center of the +- 5" diameter cleanout port on the tank. I left the fill hose connected but checked at the fill cap with soapy water for leaks, as well as checking at all other connections, at the fuel guage, etc. I used a short piece of 1/4" fuel hose and clamps to go from the supply line fitting to the return fitting to seal both of those off. I then used my dink air pump to fill the tank to 3 psi via the vent fitting using some 5/8" plastic tubing. I used my dink air pump guage at the cleanout tapping. Once pressurized, I folded the hose going from the air pump to the vent fitting and clamped with vicegrips, since the air pump had numerous minor leaks. This setup worked well and the tank held pressure overnight, though the pressure did vary slightly due to ambient temperatures. The tank was empty of fuel while testing and the pressure must be kept below 3 psi or the tank may deform or crack. 3 psi over one sq ft = 432 lbs on that sq ft!! Good luck (Probably 2-2.5 psi is enough in retrospect)