Inside my 31 Fuel tank.

[trungie]

Hello everyone,

This is a project 31 that I picked up not too long ago. The boat came with Cat 3208 so the fuel tank never seen any ethanol . But after I put a camera inside the tank, it seems to be very dirty. Is this worth salvaging, or should I look into a new tank.

What do you guys think?

Thanks!

https://youtu.be/yhjWfApwKDg

[Tony Meola]

The fiberglass tank if good is hard to beat. I am not sure what we are actually seeing. Looks like it is gummed up, but maybe it is just some type of algae. Before I would trash the tank, see if you can talk to someone who cleans tanks.

[Yannis]

Search “Cleaning fuel tank” and “Diesel tank Q” threads.

I had the same, if not worse, the thing is I had to open one inspection hole in EVERY baffled compartment.
The rest was elbow grease...

Good luck.

[trungie]

Search “Cleaning fuel tank” and “Diesel tank Q” threads.

I had the same, if not worse, the thing is I had to open one inspection hole in EVERY baffled compartment.
The rest was elbow grease...

Good luck.

What did you do with the holes that you cut into each baffled compartment? Its looking like I'm going to have to go the same route, as its looking pretty bad in this compartment as well.
https://youtu.be/vBlkPwBPapA

[Yannis]

Look at the threads I suggested, there are old pics of the inspection holes.

I cut oval shaped holes above each baffled compartment, making sure that my arm could fit through.
I then marked with a marker the position of the drill holes around each opening, around 20 of them. Use a ruler for even distribution of the drill holes.
Took a thin plywood scrap, made a hole in the middle, so I could hold it from, and inserted it in the tank. I then drilled the tank and plywood simultaneously so now the ply would serve as a template for use on the SS “oval ring” that would be inside the tank. I transported the template’s drill holes onto this oval ring and welded all the bolts onto it. This ring goes inside the tank and the bolts come out from the drill holes of the tank.(while you drill the tank and ply, make two opposite drillholes first and secure the ply onto the tank with bolts; this makes it easier for the rest of the holes to drill as the ply doesn't move around).
Then I made the top part, the external dimensions of which are identical to the ones of the inside ring and used same template to drill holes.
Then I took this assembly to the shop and cut gaskets that would sit on the outside only.
Lastly, I inserted the bottom part into the tank, pushed upwards so that the welded bolts come out, positioned the rubber gasket in place and fit the top surface, I then put the nuts which I tried to tighten in a diagonal fashion.

Every year since, I remove the deck to take a look and so far everything is ok. Occasionally I tighten some of these nuts a bit.
I wish I had the patience to trim those bolts to just above the level of the nut so I don't pierce my shoes every time I walk on them, but this is for another life.

This was the first part of the job. The other part is the cleaning...

Good luck!

[Raybo Marine NY]

I’ve used these on diesel tanks, they work great and allow for easy access in the future

http://www.seabuilt.com

[bob lico]

good product Robbie and that will work for sure.

[trungie]

Thanks for the input guys. Before I purchase 6 of the 8" Seabuilt access plates, Do I need to worry about the condition of the fiberglass even though it has always been a diesel tank?
Im assuming that there are a total of 8 baffled compartments, judging by the shape of the top of the tank. Am I correct about assuming this?

https://drive.google.com/file/d/12eSGti ... sp=sharing

[Yannis]

Raybo,

This one looks identical to mine, only mine were custom made, I didn't even know they were available on the market.
Oh, the price is also very...different!

[M. REY]

some one talk me here to clean it using a good degreaser and at the same time introducing an air compressor hose through the buffle openings inside the tank and let the bubles help to remove the dirt. if you tie a small stick to the hose will give you some play.
hope it helps......

[Yannis]

M. Rey,

Perhaps. For some relatively dirty tanks perhaps this could work.
In this case of solid crust, and in my case before, a scalpel at first, followed by acetone in QUICK hard strokes was the only solution.
And one big black bag full of synthetic (no cotton-no lint) rags from a gas station or a garments’ company.
Long sleeves to protect your upper arm from severe hardship around the rim of the tank hole.

[Raybo Marine NY]

We usually clean them with degreaser and water. Light scuff pad on the end of a stick . X

They include gaskets , hardware and are nice pieces, suggest paying the difference and just getting the stainless versions.
Don’t forget to string them up when installing the Bertram tank is deep you don’t want to have to try to reach in there to grab it if you drop it.

It’s easier for me to hand someone the bill than to fabricate from scratch, I don’t have a machine shop or metal fabricating tools.
Last time we used them was on aa fortier and they don’t install fuel senders on any fortier so we installed the sender right on the plate .

[Rawleigh]

I wonder if you couldn't put some 5200 around the inner part so that it would stick to the tank and not fall down when you open it up again?

[Yannis]

Good idea.
Although it doesn't fall because the screws are many and are snug through the tank drill holes.
Also, the gasket on the outside is snug around the screws.

[Mark]

Assuming you already have asked this question of yourself but just in case,,,Before you clean that tank, is the 170 gallon capacity enough for your purposes?

Mark

[Yannis]

Good question!
I have a 28 with 520-550 liter capacity, good for 150-170nm plus reasonable reserve.
Wish I had more, but I wouldn't care going through the expense and hustle of adding another what? 50-100 more liters?
Besides, I carry 2X100 liter flex tanks with water where the expanded diesel tank would reach.

[Raybo Marine NY]

You can countersink a small bolt into the glass and either tap the inner plate or bolt it. I didn’t bother because both sets of tanks we used them on you could reach in without too much trouble

[Carl]

I wonder if you couldn't put some 5200 around the inner part so that it would stick to the tank and not fall down when you open it up again?

I'd make certain 5200 is compatible with diesel fuel first.
I believe it softens with some chemicals.


If worried...drill undersize and tap the fiberglass.