Oil tank placement between stringers

[SailorChlud]

Good Morning: I am thinking of digging out the foam between the stringers in my 1972 Seafari in the rear starboard locker so that I can mount the oil tank lower. In essence, cutting an 7.5 inch by 10 inch rectangle of foam out. As of now my tank sits on top, but it takes up a lot of room in the locker so that taking the battery in and out is a pain, and water puddles on the top of the foam area.

I was thinking about turning the oil tank 90 degrees, so that the width is about 7.5 inches, and was hoping it would fit between the sides of the stringers, riding lower so I had more clearance above it.

Here are a couple of photos showing the current placement.

Has anyone dug out the foam between the stringers? If so, could you measure the clearance between them? I don't want to cut it out only to find the opening is too narrow. Thanks for the help.

[Capt Terry]

Although I dont have any photos, if you are interested in my approach I could provide some. In my ‘76 Seafari I basically added a horiz platform which seats on top of the center/keel stringer and extends towards ghe port stringer. This required an access hatch thru the splashwell, but provides storage under the port jumpseat.

[SailorChlud]

Thanks, Terry:

I already have a hatch in the splashwell, which I use to access the bilge pump, inside-mounted transducer, and fuel filter. So I don't think the tank can go down in that space too. I have a second, house battery mounted inside my port locker (which was set up as a cooler when I got the boat. I would like to keep the oil tank in the starboard locker if possible.

[Capt Terry]

Sailor-
FWIW here is what I did in 1985 to my '76 Seafari when buying a new Merc with an oil tank. I glassed up a 5/8" plywood tray and glued it down to the centerline stringer and the hull with some polyester resin thickened with cabosil; been there ever since. A few years ago used it to attach another bilge pump. The tray freed up some volume under the stern jump seat.
Best wishes

[SailorChlud]

Thanks!

[gofastsandman]

The VRO 2 is a crankcase pulse driven diaphragm pump.

The system check tach monitors fuel vacuum and will sound an alarm
and light Check engine". This means the pump has exceeded its ability to draw fuel.

About 4.5" of vacuum. This limitation also applies to oil. I would keep the oil tank as
high as possible to avoid starvation and boom.

[SailorChlud]

Ah, that is very good advice - I never thought about the limitations of the pump and diaphram.