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Onboard Fuel Storage   Total Page Hits: 182

Post Type: Technical/Project

Boat Part: Cockpit

Date Modified: 06/09/2023 03:07 AM

Details

Thanks to a thread on the Montgomery Facebook group, I faced up to the fact that storage of the remote gas tank for my outboard motor was unsafe. Mounted in the aft compartment on my m17, the only ventilation was the four scupper holes and over the interior walls of the compartment into the cabin living space.

Ventilation requirements for onboard fuel storage are defined in ABYC H-2.6.1.2 "Ventilation of Boats Using Gasoline". I found a copy at https://newboatbuilders.com/docs/H-02.pdf.

In summary, a compartment where gas is stored must have 15 sq. inches of venting per net cubic feet of volume (total volume less physical volume of the tank and other permanently mounted equipment sharing the space). The alternative is to have powered blower. In addition, the compartment must be sealed off from the living space of the boat.

On my boat, total volume of the compartment is 3.2 c/f. The tank measures ~ 0.8 cubic feet so net volume is 2.4 c/f. - multiplied by 15 sq/in = 36 square inches of vent thus needing 5 - three inch diameter round holes (7.1 sq/in each) or 3 - four inch holes (12.6 sq/in each) to comply with the spec. Any opening totaling 36 sq, in. could be used if a suitable grille could be found.

I decided the path of least resistance (and fewest holes) was to move the tank out on deck where it now resides on the cockpit floor with the fuel hose passing through the scuppers and out to the motor. I couldn't find anything to preclude routing the hose this way. I also added a grate over the tank.

Overall, I'm happy with the new arrangement. The tiller sweeps that area so you don't notice the loss of floor space in the cockpit. My dog appreciates the extra deck space and a deck chair fits the space too. Dilly Dilly!

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