Cutting aluminium diesel fuel tank on board

[Boater On Thames]

Yes. It may have a chance that the connections between tanks will leak in the future. But at last I can remove the small tanks and replace them again. That now makes me rethink maybe I shouldn't use glue on the bottom, I should fill with expansion foam after all three small tanks slid in place so they won't move. That way, I can still remove the foam to fix any leakage in the future much easier than glue.

 

[grumpy_o_g]

Diesel is not flammable believe it or not - that means it's flashpoint is above room temperature, and you have to heat it up, usually to around 50 or 60°C, often higher, to get it burn. Basically the fuel in liquid form will cool the ignition source and quench the fire even if there is some oxygen present, just as water would. You can try it - just pour some diesel into an open container and throw a match in and the match will go out - you will need a wick to actually burn the diesel. Unless you can get incredibly good ventilation through it there's likely to be some vapour in the tank though and this can be flammable or explosive if you have a ignition source with the temperature noticeably above the flashpoint such as spark. Overall I would be concerned with using a jigsaw or a grinder on the tank partly because of sparks but mainly because of swarf as mentioned.

Having worked on boat tanks a bit and aircraft tanks a lot the three basic rules are:

• Don't put anything other than fuel in them, and that includes tools and yourself if you can possibly avoid it.
• One big tank is a lot easier to maintain and operate than many smaller ones (though big tanks bring their own design problems, especially on a/c).
• You can never have enough access to either the inside or the outside.

If you have the option for repairing externally or using a liner I would take it if it looks even slightly viable.

Note: the rules on one tank change slightly if you can switch between the tanks and fill them from separate source or have a fuel polishing system that can clean fuel and send it to a "clean" tank.

 

[sailorman]

I am planning to use a circular saw or a jigsaw.

Jig or sabre saw

 

[longjohnsilver]

Lucas, is there any bit of your boat that is still intact and working?

 

[penfold]

Rather late to this one; as others have observed diesel isn't very volatile, but if the deed is not yet done and you are of a nervous disposition then flushing the tank with a few squirts from a CO2 fire extinguisher will inert the interior and prevent combustion.

 

[Boater On Thames]

This job not yet starts as I am working on replacing the shaft seal. I think it is safe to cut the tank as I already used a gas torch in the engine room were full of diesel small. I am going to cut the shaft coupling with a grinder in the next coming few days.