Rabbit hole

[BillyK]

We are reading through and discussing Everett Collier's book, 'The Boatowner's Guide to Corrosion". Sailboat Owner's Guide to Corrosion - Basic Theories (Collier 1-4)
There are descriptions of spot corrosion in fuel tanks and such that result from poor, chipped or worn paint jobs or contact with bilge water and another metal. There is probably an underlying problem that needs to be addressed, not just a fuel tank that needs repair.
I think most of the other participants in the corrosion thread feel aluminum is a poor choice for fuel tanks.

-Will (Dragonfly)

The corrosion is right where water would collect and sit. to prevent this, i am going to drill a drain hole so it doesn't sit in water again. Is there a recommendation of how to place the tank into a bridal? Maybe put a thin piece of starboard down first so it's not sitting directly on the fiberglass?

 

[dmax]

I would epoxy some standoffs to raise the tank a bit and allow some airflow.

 

[Tom J]

We are reading through and discussing Everett Collier's book, 'The Boatowner's Guide to Corrosion". Sailboat Owner's Guide to Corrosion - Basic Theories (Collier 1-4)
There are descriptions of spot corrosion in fuel tanks and such that result from poor, chipped or worn paint jobs or contact with bilge water and another metal. There is probably an underlying problem that needs to be addressed, not just a fuel tank that needs repair.
I think most of the other participants in the corrosion thread feel aluminum is a poor choice for fuel tanks.

-Will (Dragonfly)

When the yard re-installed my tank, they put hard rubber spacers under it to prevent chafe and to raise the bottom off the fiberglass tray that could collect seawater.

 

[Will Gilmore]

I'm not yet an expert, we are only a few chapters into our study, but I think good thick and solid coats of epoxy paint to isolate the metal from contact with both another conductive metal and any possible electrolytes such as salty bilge water. The supports to keep it dry would also be good. Concentrated pitting and spot corrosion can be really bad when only small areas are exposed, such as worn paint or pin holes. The electron loss becomes concentrated at those spots.

-Will (Dragonfly)

 

[BillyK]

I'm not yet an expert, we are only a few chapters into our study, but I think good thick and solid coats of epoxy paint to isolate the metal from contact with both another conductive metal and any possible electrolytes such as salty bilge water. The supports to keep it dry would also be good. Concentrated pitting and spot corrosion can be really bad when only small areas are exposed, such as worn paint or pin holes. The electron loss becomes concentrated at those spots.

-Will (Dragonfly)

How about a good solid ground? should the tank be completely isolated or strongly bonded to the grounding system?

 

[Will Gilmore]

I don't know the answer to that. We haven't gotten that far in the reading.

I suspect part of the answer lies in how isolated one can make it. There are fill ports and feed lines and straps and bolts that connect to fuel tanks. Can they possibly connect the tank electrically to other parts of a potential galvanic cell?

-Will (Dragonfly)

 

[dLj]

I'd go to a HDPE tank. They aren't particularly expensive - depending upon your definition of expensive.

You could fix that tank, but you are getting what looks like outside- in corrosion, not inside-out corrosion. You should learn why that is to not continue to repeat your aluminium corroding. If it's sitting in water as you say, then getting rid of the water will help. I'd still go to a HDPE tank. Your image of the inside looks like you have deposits in a lot of places. I think you are just putting band-aids on top of probelms that aren't going to go away. But, that's just my 2 cents worth...

Bonding is not going to help you. Bonding is used when an object is sitting in an electrolyte. Your tank is not sitting in an electrolyte.

@Tom J - is your tank aluminum or steel?

dj

 

[Tom J]

@Tom J - is your tank aluminum or steel?

My tank is aluminum, same boat and tank as the OP. I had the tank repaired 14 years ago, and so far, so good.

 

[dLj]

My tank is aluminum, same boat and tank as the OP. I had the tank repaired 14 years ago, and so far, so good.

Sounds like a good way to go then...

dj

 

[Tom J]

Sounds like a good way to go then...

dj

Maybe not for the OP, though. My tank was only two years old, and was in like-new condition. The leak was a pinhole in a welded seam, no corrosion involved, so I opted for the repair. The corrosion in the OP's tank is another matter. I only offered my experience with the fuel tank as an example of what could be done with an aluminum tank in good condition.

 

[BillyK]

Ordered the tank today. 5 week turnaround.. close to cutting into the season but it is what it is. oddly the schematics that Catalina Yachts sent me were completely different than the tank i have. The schematics on catalina direct's website matched perfectly other than the fuel pickup needing to be moved towards the center of the tank.

Here's the two to compare..
Its odd to me that Catalina Yachts would have the wrong specs for what seems like the correct tank for my boat.

 

[marchem]

Ordered the tank today. 5 week turnaround.. close to cutting into the season but it is what it is. oddly the schematics that Catalina Yachts sent me were completely different than the tank i have. The schematics on catalina direct's website matched perfectly other than the fuel pickup needing to be moved towards the center of the tank.

Here's the two to compare..
Its odd to me that Catalina Yachts would have the wrong specs for what seems like the correct tank for my boat.
View attachment 175636

View attachment 175637

I know Catalina used at least two different tanks, with different fitting locations, for the C310. Here’s a picture of the label on ours, Hull #31.

 

[Tom J]

Ordered the tank today. 5 week turnaround.. close to cutting into the season but it is what it is. oddly the schematics that Catalina Yachts sent me were completely different than the tank i have. The schematics on catalina direct's website matched perfectly other than the fuel pickup needing to be moved towards the center of the tank.

Here's the two to compare..
Its odd to me that Catalina Yachts would have the wrong specs for what seems like the correct tank for my boat.
View attachment 175636

View attachment 175637

I like that your fuel pickup will be near the center of the tank. Mine is way over to starboard, a real pain when motorsailing on starboard tack.

 

[Witzend]

Mine failed a couple of years ago. The problem is that Catalina created a lip on the molded area of the fibre glass at the lowest point of where the tank sits. This tends to collect water especially if the bolts that hold the ladder start leaking, as you would expect from the torque they endure when climbing. I partially collapsed the holding tank to get it out. Had the tank repaired and had then cut the port side corner off so I could get it back in easily.
I also put a spacer under the edge of the tank (where the water would want to sit to raise it up.
PIA job for sure!

 

[BillyK]

Mine failed a couple of years ago. The problem is that Catalina created a lip on the molded area of the fibre glass at the lowest point of where the tank sits. This tends to collect water especially if the bolts that hold the ladder start leaking, as you would expect from the torque they endure when climbing.
PIA job for sure!

I'm going to drill a hole at the low point in that cradle so if water does collect, it has somewhere to go.. i'll have to put another hold at the bottom close to where it's glassed to the hull so it can get out of there as well..

 

[Cat 310 #1 in GA]

Am jumping into this thread because I am in the middle of a cruise south, have made it to Stuart, Florida and discovered diesel in the bilge. Not a leaking hose of course but a pinhole near the weld of the fuel tank. Am attempting a fix with a roll of epoxy putty that we applied yesterday as it was leaking. Seems to have stopped the leak but too soon to say for sure. Going to inspect it this morning. Then have to decide if I can travel back 250 miles to home or will I need to go to a local yard to have both fuel tank and HWH replaced. Hull #1.

 

[JRT]

Good Luck @Cat 310 #1 in GA are you on your original fuel tank and Hot Water Tank? I assumed that is what HWH is. My tank seems fine, checked it last Friday, but did notice some rust on the bottom of my hot water tank edge and the drain was leaking a few drops, so I tighten the handle up and it seemed to help.

 

[BillyK]

Good Luck @Cat 310 #1 in GA are you on your original fuel tank and Hot Water Tank? I assumed that is what HWH is. My tank seems fine, checked it last Friday, but did notice some rust on the bottom of my hot water tank edge and the drain was leaking a few drops, so I tighten the handle up and it seemed to help.

i know you didn't ask me.. but my HWH was shot as well.. rust and leaked. it was bypassed by the PO and right now its sitting in the dumpster at the boat yard.. i'm planning on replacing it next winter when i upgrade all the water lines to pex over the vinyl that's in there now. will most likely stick a 5 gallon one in there. we literally never used the one in our Catalina 30 that we had for 9 years prior to this boat.

 

[JRT]

@BillyK they do seem to rust out and I know I'll have a replacement down the road too, just would like to hold off this year. I could not get away without the hot water now that my wife uses it and loves it for our day sailing. I already showed my wife @JK_Boston_Catalina310 awesome hot water tank and rum conversion so if I have to replace I'll follow his path!

 

[JK_Boston_Catalina310]

Ordered the tank today. 5 week turnaround.. close to cutting into the season but it is what it is. oddly the schematics that Catalina Yachts sent me were completely different than the tank i have. The schematics on catalina direct's website matched perfectly other than the fuel pickup needing to be moved towards the center of the tank.

Here's the two to compare..
Its odd to me that Catalina Yachts would have the wrong specs for what seems like the correct tank for my boat.
View attachment 175636

View attachment 175637

Hull #65 has the top tank pictured. Make sure you add inspection ports on both sides of the baffle or one over the baffle so both sides can be accessed for cleaning. When I eventually get a tank made I also plan to have a second set of pickup and return installed for a polisher.

If you drill a weep hole, please post a pic. Curious to see how that goes.

On the factory water heater (no such thing as a hot water heater/tank ), I had to cut away some glass on the opening on the starboard side of the rear bulkhead and take everything off the front of the factory water heater to get it to rotate and fit out. The wood board screwed to the bulkhead still covers the opening even with the extra cuts. The front mounting flange was bolted down as you can easily see. The rear flange goes into a slit cut in the fiberglass shelf for the refer compressor. So you need to start by pulling the water heater towards the rudder post. Removing the steering cables would help this a lot.

Good luck

Jesse