Maybe a Tank Change, Catalina 27

[philwsailz]

I posted this question in my "big" thread but I'll post here as well.

My C27 is inboard powered with an A4. Stock gasoline tank is intact.

I'm considering scuttling the onboard tank for portable tanks. Stock tank is sound but inside "living" space. Optional tank location is sealed a 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.

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

Thoughts?

 

[Ralph Johnstone]

External tanks would be above motor. Prone to siphon flooding maybe.

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

Maybe a 1/4", 12V, normally closed, solenoid valve ? Asco is a good quality valve for this application. Be sure it's rated for gasoline.

 

[centerline]

The fuel lockoff valve is a good option, but i dont think there is any greater issue with your proposed tanks than there is on any other type boat that has side tanks or tanks that set on the sole with the engine setting low in the boat on its stringers... although these applications do require the use of anti siphon valves at the tank fitting... which are only a simple inline check valve, and the fuel pump suction has to overcome the slight spring pressure to suck fuel thru it...

 

[Benny17441]

Optional tank location is sealed a self-draining from a flammable vapor perspective.

Thoughts?

Not sure if that means the location is vented to the outside of the hull. Gasoline fumes are heavier than air and will pool at the low spot of an enclosed space. Tanks installed inside the hull are usually sealed and only vented to the outside but portable tanks with vented caps which would allow fumes to escape into a sealed space might not be recommended.

 

[philwsailz]

Not sure if that means the location is vented to the outside of the hull. Gasoline fumes are heavier than air and will pool at the low spot of an enclosed space. Tanks installed inside the hull are usually sealed and only vented to the outside but portable tanks with vented caps which would allow fumes to escape into a sealed space might not be recommended.

That aft lazarette compartment is sealed off from the interior, was designed for fuel storage and has scuppers at the compartment's floor level. It is an ideal location for fuel. Any leak would vent to atmosphere and not the cabin. The design of the space as a fuel storage space is great. I just don't want fuel running out of the carb due to the elevation difference Between a portable tank and the carb.

 

[philwsailz]

I am going to ask same questions over on the Moyer A4 forums. I'll share any further insight those guys have here.

 

[centerline]

portable tanks with vented caps which would allow fumes to escape into a sealed space might not be recommended.

if using the new EPA/CARB approved fuel tank cap, there should be no escaping vapors from the tank, so as long as the portable tank is permanently and completely isolated from the living space of the boat, there should not be a problem having it in another enclosed space, vented or otherwise....

 

[Benny17441]

Good enough.

is sealed off from the interior, was designed for fuel storage and has scuppers at the compartment's floor level. I just don't want fuel running out .

Good enough, just covering all bases. If it was me I would go with a manual petcock fuel shutoff valve installed in a convenient location. It is simple, effective, long lasting and inexpensive. It should not be hard to quickly establish a routine where you open the tank vent and fuel shutoff valve and then when done close them both. Have never been a fan of check valves and solenoids as they can fail when least expected.

 

[Benny17441]

if using the new EPA/CARB approved fuel tank cap, there should be no escaping vapors from the tank, so as long as the portable tank is permanently and completely isolated from the living space of the boat, there should not be a problem having it in another enclosed space, vented or otherwise....

Call me old school but I think these new one way vented caps may not be a substitute for a properly isolated and vented compartment. Don't know enough about their efficacy, reliability and anticipated useful life to feel comfortable with doing away with proper vents. Perhaps in the future. Don't get me wrong they are an improvement over the current vented caps and should enhance safety to all currently in use tank holding compartments.

 

[weinie]

Phil,
Just glass the tank back in and be done with it. Time to go sailing on that thing!!!!

 

[centerline]

Call me old school but I think these new one way vented caps may not be a substitute for a properly isolated and vented compartment. Don't know enough about their efficacy, reliability and anticipated useful life to feel comfortable with doing away with proper vents. Perhaps in the future. Don't get me wrong they are an improvement over the current vented caps and should enhance safety to all currently in use tank holding compartments.

at one time I felt the same way and would have agreed with you, but that has changed.
here is what I know about them thru experience..... if the cap is functioning correctly, you can have a tank of gas setting in the hot sun for hours with the cap screwed on snug, and the tank will expand and become round like a beach ball....there is no exaggeration here. the tank actually got so round it rolled over on flat concrete, with the cap and hose resting on the ground.... without leaking. (I was running a large outboard on an engine stand outside and left the tank set out near it)
I dont know what would fail first, the tank bursting, the lid blowing off the tank, or the vent rupturing, but it does NOT allow vapors out with even a little bit of abuse.
if one needs to, the cap can be loosened on the tank a quarter turn to prevent the beach ball effect, and still act like an old fashioned "open to atmosphere" vented cap, but it defeats the purpose of the EPA/CARB venting system, and is not intended to be used in this manner.
(this is how I have mine at this time so it doesnt have to withstand the sun/pressure test again)

I have had the new caps on the tanks in my 25 for a little over 2 years, and they work great.. never an escaping fume.

they WILL easily allow air in as the fuel gets used, but not out.... no more gasoline smells when it gets agitated, or the sun hits the tank.

because of this pressure differential, when one goes to switch hoses to the 2nd/reserve tank, one has to loosen the cap first to depressurize the tank, or you WILL get a spray of fuel when you try to connect to the new tank...
on the boat I am currently working on, I am have installed the "sprayless" quick change fittings, and hopefully it makes a difference.

AND, when you grab a full tank to carry it to or from the boat, there is no worry to close the vent to keep it from leaking out the cap.... it just doesnt.

it actually is a good dependable product at this time....

 

[philwsailz]

Here is the discussion going on over at Moyer Marine's website. Typical bench racing stuff: http://www.moyermarine.com/forums/showthread.php?t=9521

My takeaway so far is this:
Cheapest solution is to repair what I have and monitor it for leaks, (I already installed new shutoff valve and will turn on and off with raw water seacock).
The C27 lazz as designed should be suitable for fuel storage if portable tanks are used
A shutoff valve is going to be necessary when away from the boat regardless of installation
No firm opinion on an ignition circuit - energized solenoid valve; that needs more research.

Go take a look at the thread as it evolves over there and ask any questions you might have here. I am going to continue to, as I have time, look for a circuit-controlled valve that hopefully meets SAE J1171.

In the meantime I know I need to move the blower power OFF of the ignition circuit and onto the continuous power circuit behind the control panel. I want to run the blower for a while prior to even turning the key on. Right now you get no blower without the key, and the temp / pressure alarm also sounds. That's pleasant. NOT.....

 

[woodster]

Phil
they make a lock out timer for the blower that will not let you start the engine for 5 mins when you power..... up you may want to look at that

 

[The Garbone]

Here is the valve I am using as a cut off.


SeaSense NPT Female Three Way Valve, 3/8-Inch
by SeaSense
Link: http://amzn.com/B004XAFKB2

The shaft is long enough that you can drill a hole in the galley cabinet and mount said valve and the knob ends up flush. Pretty nice.

 

[philwsailz]

Phil
they make a lock out timer for the blower that will not let you start the engine for 5 mins when you power..... up you may want to look at that

I may look into that, but I usually turn the blower on prior to firing up the motor as a first step in some other routine, opening the cabin, securing bumpers when heading out... On return to the dock I will usually fire up the blower while dousing the main and throwing the cover on, etc. I would hate to be on a tack, with some bonehead on collision course and me needing the iron Genny RIGHT NOW and have to wait 5 to crank it.

Here is the valve I am using as a cut off.


SeaSense NPT Female Three Way Valve, 3/8-Inch
by SeaSense
Link: http://amzn.com/B004XAFKB2

The shaft is long enough that you can drill a hole in the galley cabinet and mount said valve and the knob ends up flush. Pretty nice.

That is slick. I will remember that if I make the tank move. It does not appear to have an OFF position but a plug on one of the inlets would sure do the trick for a single tank. I could put that through the bulkhead between the aft lazz and the cockpit... easy to flip the fuel off after killing the motor.

 

[woodster]

good point about the bone head