1975 Catalina 27. Use of portable tanks in aft lazarette

[philwsailz]

m

My C27 is inboard powered with an A4. Stock gasoline tank is intact, but it has popped loose from its tabbing AND it's the original tank.

I'm considering scuttling the onboard tank for portable tanks. Stock tank is sound but inside "living" space. Optional tank location is sealed and self-draining from a flammable vapor perspective.

Onboard tank is below motor. Fuel pump overcomes Gravity. External tanks would be above motor. Prone to siphon flooding maybe. Is it safe or advisable to have the fuel tank upwards of a foot above the carburetor?

I don't want a gravity-fed fuel leak due to a poorly seated bowl valve.

Thoughts?

[ndutton]

Life's a trade off.

The existing tank may be inside the cabin space but it's ventilated per USCG standards by the bilge blower. The laz may be sealed from the cabin space but it's not ventilated to spec and it's higher than the carburetor as you observed. There are anti-siphon tank valves available to resolve the gravity feed concern (also a USCG requirement) and a manual shut off valve immediately ahead of the carburetor is in order but powered ventilation of the laz is imperative if it is to become a fuel compartment. I'd study the tank venting requirements carefully as well. I believe it's required to be vented overboard. We have a Standards forum category with all the pertinent information.

If the existing tank is sound and clean, I'd look at re-securing it. If not sound and clean, I'd consider replacing it with a Moeller poly tank. Please consider that there are thousands of Catalina 27's manufactured with the tank in the stock location without issues.

[thatch]

Phil, I did exactly what you are contemplating on my Cat 30 a few years ago after finding a small leak at the lowest point of the original aluminum tank. That tank had an anti-syphon valve and a shutoff valve which I just transferred to the new Moeler tank. Another modification that was needed during the change was to move the fuel fill farther aft, nearer the new tank. I do not use any kind of sealing gasket on that compartment, so I feel that it is fairly well vented. One bad design feature on the C-30's is that the fuel fill will become completely flooded during a washdown. The new location has proven to be a in much dryer location. I have had zero problems with this change and have gained some valuable storage space inside the cabin.
Tom

[JOHN COOKSON]

Don't Quite Understand Current Tank Location

m
Stock gasoline tank is intact, but it has popped loose from its tabbing AND it's the original tank.
Stock tank is sound but inside "living" space. Thoughts?

Phil
I also have Cat 27. The factory installed tank is located under the starboard quarter berth right next to A4 on my boat. I don't consider that area to be "living space" at all. More like inside the boat but out of the way. By any chance is the current tank on top of the starboard quarter berth? Where exactly is the current tank?

TRUE GRIT

If the current tank is under the starboard quarter berth an option would be to render it non explosive cut it up to remove it then put in two smaller cross linked plastic tanks in its place with a tank1, tank2 selector. Or just go with one smaller tank. Depending on how you use the boat a smaller tank might work for you? This way you wouldn't have to cut the quarter berth to get the existing tank out or new one(s) in.

[The Garbone]

We had a 74' C27 with factory outboard. It had 2x 6gallon saddle tanks in the act lazerette with a cutout in the middle for the motor. I would think it would be easy to put a set of tanks in and proper vents.

One thing I discovered is it was easier to leave the tanks in place even though I could remove them and fill them with a siphon.

On our C30 I think the tank level is above the carb at least when full, I have a easy access shut off valve just to be safe.

[philwsailz]

Phil
I also have Cat 27. The factory installed tank is located under the starboard quarter berth right next to A4 on my boat. I don't consider that area to be "living space" at all. More like inside the boat but out of the way. By any chance is the current tank on top of the starboard quarter berth? Where exactly is the current tank?

TRUE GRIT

If the current tank is under the starboard quarter berth an option would be to render it non explosive cut it up to remove it then put in two smaller cross linked plastic tanks in its place with a tank1, tank2 selector. Or just go with one smaller tank. Depending on how you use the boat a smaller tank might work for you? This way you wouldn't have to cut the quarter berth to get the existing tank out or new one(s) in.

Well you are correct. The space the tank occupies is technically in the engine compartment. Thing is, with current ABYC and USCG rules regarding bulkhead separation of engine spaces, so is the bilge... Yes, my tank is under the starboard quarter-berth... with really no solid isolation bulkheads between the tank and the cabin. As an ABYC/NMMA member I know the 40-yr old boat does not meet current standards... To me th tank IS in the "living space" of the boat.

If tank elevation were equal, fuel storage in new tank(s) in the self-draining open-to-atmosphere aft lazz would remove one source of explosive vapor from the interior.

I have not ruled out either solution yet, but central to the decision is how elegantly a guy could implement an automatic fuel shutoff to prevent siphoning, if even it is an issue. Or a manual shutoff...

So... Issues are defined Both options have their benefits. It becomes in my mind about a 50/50 trade off. Central to the decision I how to implement a fuel shutoff, simple or mildly interesting.

I do prefer new tanks in the vented and self-draining lazz IF I can with piece of mind know I can do it without draining the tanks straight into the bilge. The fuel storage location IS Infinitely safer.

[Al Schober]

My recollection of Cat 27s is that they came in the inboard and outboard versions. The outboard version had the engine in the lazarette along with the fuel tank - all open aft, draining aft, and isolated from the cabin. The inboard engine was a conventional inboard installation.
I would be very leery of trying to use an outboard tank for an inboard engine.
I formerly had a Morgan 24 with an outboard, and after issues with the tank in the cockpit, moved two tanks to the space below. After initial fuel starvation issues, an electric fuel pump moved fuel to the engine nicely. Plug in the full tank and away you go.
Didn't realize at the time how I was flirting with death - any vapors from the tanks went into the bilge - where we were living. And outboard tanks vent to their surroundings, not overboard like inboard tanks.

[hanleyclifford]

I added an extra tank as shown. The detachable venting parts are from McMaster. Not shown is the bungi hold down arrangement and the required shut off valve.

[JOHN COOKSON]

Phil
You may be on to something good moving the tank to the lazaret. Thinking how my Cat 27 is put together.*.....The tank fill is on the very end of the starboard cockpit combing and the vent is on the starboard side high and to the right (when viewed from outside the boat) on the stern. I don't see any reason why you couldn't use the existing fill and vent to a tank in the lazaret. This arrangement would keep any fumes from the tank out of the hull area. You could put a gas vapor detector in the lazaret for added peace of mind. This should work well because it is a closed space. Any vapors or spillage would stay in the lazaret not in the "living space".
* Hull #4446 built in 1979

TRUE GRIT

There is one disadvantage which may or may not be important to you: You're moving weight to the end of the boat.

[ndutton]

Party pooper

Are Al Schober and I the only ones who think this is dangerous? We are discussing portable tanks inside the boat. The USCG is very specific about and have good reasons for requirements for such installations. Just for the tank there are shock test, fire test, pressure test, labeling, grounding of all metallic parts and powered ventilation of the space. Heaven forbid there's ever an incident but if there was the insurance adjuster would likely red stamp the claim and you're on your own.

For the record, I remember Phil from back when I frequented (struggled with) SBO and his work is exceptional, one of the really good guys over there.

[hanleyclifford]

Here we see the Bayliner arrangement. I'm sure there is no USCG or insurance problem or it wouldn't be built.

[ndutton]

Really?

The example offered is a 16 foot outboard powered Bayliner Element bow rider in comparison to our inboard auxiliaries? Perhaps a wider angle view of the Bayliner installation will tell a more complete story:

Look, you can have any gasoline tank installation you want. Advocating it for others is another matter.

[hanleyclifford]

The example offered is a 16 foot outboard powered Bayliner Element bow rider in comparison to our inboard auxiliaries? Perhaps a wider angle view of the Bayliner installation will tell a more complete story:

[ATTACH]11575[/ATTACH]

Look, you can have any gasoline tank installation you want. Advocating it for others is another matter.

Sharing information does not constitute advocating.

[hanleyclifford]

Also, note that the Bayliner installation does not feature individual overboard ventilation for the tanks - mine does. The Bayliner installation does provide side ventilation (as does mine) but I suggest that fumes could build up on that Bayliner installation just under the hatch.

[ndutton]

Here we see the Bayliner arrangement. I'm sure there is no USCG or insurance problem or it wouldn't be built.

Enough said.