Gas Tank Below

[cuisto]

I have a welded aluminum Gas Tank in excellent shape, aprox 20 gal. It has an inflow out flow and vent. I would like to be talked into installing this on my It would free up cockpit storage ad move COG lower in the boat. Am I NUTS.

[DLT]

KMC has done something similar...

[Chip Hindes]

My personal experience with built in boat fuel tanks, even those in excellent condition, is that they inevitably leak. That's bad in any boat, but in a power boat at least, there are bilge blowers and underway compartment venting systems specifically designed and sited to clear the fumes. Not so in a Mac.

[kmclemore]

Yes, I do indeed have a tank below decks, with full venting and a sealed enclosure. See pics here:

http://macgregorsailors.com/phpBB/viewt ... 2014#42014

... and more description here...

http://macgregorsailors.com/phpBB/viewt ... 3461#33461

The gas tank is made of one piece molded cross linked polyethylene and meets or exceeds industry standards (ABYC, USCG, CE and ISO):


.. and it is secured to the aft berth's sole with a metal hold-down bracket kit made for the tank.

The Perko fill & overflow vent that was used:



Enclosure is made of wood and marine panels, and sealed with a fillet of 5200 on all sides, edges and top. Venting is passive and active, and vented air exits out of the pedestal base (see pics for the chrome vent).

[Frank C]

The ABYC publishes guidelines for permanent fuel tank installations. You can't just "read" them because you need a subscription, but I'm pretty sure KMC's installation hits all the high points ... sealed locker, active & passive ventilation. A few others have installed tanks with none of those precautions, but I wouldn't. I also wouldn't buy a boat that had been modified without following guidelines.

[kmclemore]

Yes, indeed I do think it complies, Frank. In addtion, I forgot to mention that the front cover of the sealed compartment is removable for annual inspection and the fuel tank was grounded with a proper ring-and-post mounting.

[Night Sailor]

If you motor more than you sail, I think it would be a worthwhile endeavor. I had a 30 gal on a 30' boat once and since I only used the motor to get out of the docking area, the gas would get old before I used half of it if I filled the tank, and the aluminum tank created condensation water in the fuel if I didn't keep the tank full. I'd say don't do it, if you mostly sail. Or in any case, use plenty of insulation around the tank or the sealed locker to help reduce condensation.

[kmclemore]

I agree, you do have to do a fair bit of motoring to make it worthwhile, and we do. However, it also serves to open up the cockpit storage lockers for other uses, and we use that to great advantage.

[James V]

If you can avoid it, please do so. An outside tank with lots of fresh air and any spills/leaks running outside the boat and you can take the tanks out and clean/replace when needed is much better. The fumes just go boom to easily.

On my M I have 2 - 12 gal and 1 - 5 gal and 1-1 gal. More than enough to go 100 miles at WOT and over 300 at 5 mph. I can always get fuel in those miles.

[Hardscrabble]

Our 2001 X has a 25 gallon aluminum tank below deck. We purhased the boat from its second owner last summer. The story is the original owner was a merchant sea captain and had installed several upgrades (which are evident). I was rather concerned also and throughly inspected the installation before purchase. It is an excellent installation and we have had no instances of leakage. IF we ever do any extended trips, I think it will prove its value. I understand the original owner did cruise to the Bahamas at some point.

[Spirit of the Wind]

Two years ago I installed a 26 gallon permanent aluminum fuel tank from West Marine at the aft end of the rear berth on my . The fuel fill is on the floor of the port cockpit locker, just inside the lip. The vent is on the port aft side of the hull. I tried to find the appropriate standards for securing it in place, proper venting and proper ventilation. I located a link to the Canadian standard which for the most part incorporates the ABYC information. It can be downloaded for free. I've included the link below.

http://www.tc.gc.ca/marinesafety/TP/TP1 ... ersion.htm

Properly installed and inspected periodically, I don't think a permanent fuel tank represents a threat. I also ordered and installed cockpit locker covers from Aussie Bob so that I can store my barbeque and other material securely in the cockpit.

Bob Cameron

[mtc]

Anyone try to mod the aft area sole?

My plan is to find a polymer tank that will fit between the hull and rear berth sole. I've found one 7" tall with a 48" x 18" footprint. Running this tank centered in that rather useless space would:

1. Aid ballast - fuel weight below centered and a tad more forward than those high 24 gal tanks on deck would increase the M's resistance to heel, though probably by only a trace amount, it's still a step in the right direction.

2. Give me the cockpit sole area I'm longing for.

3. I'd be able to seal that area with a little work. I've even considered 'raising' the berth height with a plywood sole, essentially turning the empty space below the aft berth into a functioning fuel cell (not a 'wet' cell, but with two tanks running longitudinally in tandem), plumbing, passive and active venting, etc. Would probably only need another few inches for height.

Thanks, guys for the links and the ideas. Kevin, love your fill method, simple and to-the-point.