O Day 25 below deck outboard fuel tank

[sunshinemartini]

I have an O Day 25 that I am planning on doing longer range coastal travel in Lake Huron. To accomplish that safely I need a larger gas tank for the 15 hp outboard given the distance between marinas with fuel. I will be placing a gas tank below deck of course vented properly and with the correct fill and below deck blowers as an added safety feature. My question is location with an eye towards maintaining boat balance (fore aft and side to side). Two options are, first, to re-locate the water tank to the bow and replace it in its previous location with a gas tank and fill/vent in the cockpit. second to locate 2 smaller gas tanks below each of the port and starboard settees in the cabin leaving the water tank as is. The boat is perfect for us and given all the upgrades already accomplished not looking to sell it.
Need responses from owners who have done this with photos if possible and what effect it had on boat balance.

 

[RichBone]

I found 2 Merc portable 3 gal tanks that fit in my port gas locker in the cockpit. With 15 hp running at 1/3 to 1/2 throttle should get you to hull speed I'm thinking. 6 gal should easily get you 25-30 miles. You could always strap down an extra tank in the aft end of the cockpit sole.

 

[sunshinemartini]

Thank you for the reply. Ours is an 1985 O day 25 we have had for over 10 year and its old home port was in Lake St. Clair Michigan which I am sure you know of. Your estimate on fule consumption/hull speed is correct; however, the new sailing waters present a different set of conditions that require a larger reserve of fuel as a safety measure.

 

[BelladonnaII]

While I would probably lean towards using one of the tanks mentioned above that will fit in your gas locker I will add this note. My 26' previous owner apparently moved the water tankage to the bow (or it was there originally, I've seen different ways). Either way, that now leaves the water tankage, and holding tank both in the bow which makes the boat bow heavy and causes the cockpit to not drain very well at the dock when nobody is aboard. So having said that I would love some added weight in my stern (which I'll be doing with an extra house battery or two.

 

[ebsail]

We also make long trips in our 25 with a 9.9 2 cycle. We just carry a couple of premixed 6 gal tanks (one in the cockpit, aft) and a siphoning clear plastic tube with a valve and squeeze bulb. When the primary tank is getting close to empty, we just pull out a 6 gal and siphon the fuel into the primary tank. This can be done while the engine is running.
The fuel pump on these outboards is fairly puny and it might not be able to lift the fuel from a low tank. We get about 30 miles per tank at 5K.