Do we really need 2 separate gas tanks?

Sea Wolf

The general theory in the past has been that we needed 2 separate gas tanks so that if we got bad gass (e.g. contaminated with water), we could switch from one tank to the other. This assumes, I guess, that only one tank would get the bad gas, which would certainly not always be the case.

This is probably a legitimate concern when fueling up in SE Alaska at villages or the like, but how often do we run into this in normal domestic use?

With the 10 micron fuel filters with visible bowls and drains that are used on today's EFI engines, it would seem that this two tank scheme may not always be necessary, depending on where you typically fuel up.

I'm thinking that if a simple inverted "Y" and a shut-off valve above were substituted for the off-1-2 valve usually installed in the boats, that there would be two advantages gained:

1. The weight loading port and starboard would be equalized by the liquid seeking a common level, eliminating the shift in weight / balance as one tank at a time was emptied. The weight shift is a bothersome effect to some of us.

2. The need to shift the switch from 1 to 2 (or vis-a-vis) when approaching the end of one tank would also be eliminated, gettng rid of one more bothersome detail.

Can you folks think of reasons why this wouldn't work under the conditions above where gas quality is almost never an issue? (I've had none in 9 years with the C-Dory.)

Joe.

Da Nag · Posted: Fri Mar 10, 2006 2:04 pm Post subject:

Hey Joe...remember this thread?

Mr. Green

Sea Wolf · Posted: Fri Mar 10, 2006 2:33 pm Post subject:

Bill-

Deja-vu' (sp?)...15 months later!

I'm not sure all the plumbing proposed would be necessary, nor all the worries about dire consequences = stopper consideratons, at least in my present state of mind. which is not saying much!

Will mull it over for a while longer!

I'm thinking that the upside down Y with the shut-off valve could parallel the existing set up and that set up would be the default operating system when the valve was closed.

Good memory, Bud!!!

Joe.

DodgeRam · Posted: Fri Mar 10, 2006 7:59 pm Post subject:

Memory is like a bar soap , the more we use it, the smaller it get!

Gary SEARAM

oldgrowth · Posted: Fri Mar 10, 2006 8:30 pm Post subject:

I have given it thought and have decided that after I add the extension on my boat, I am putting in one 40 gallon built in tank. I will carry a 6-gallon portable tank for a reserve.

Norm S · Posted: Fri Mar 10, 2006 11:11 pm Post subject:

40 gallons...Holy #$%@ How long do you stay out and how far do you need that little honda to take you? Only concern I would have is that is about 250# pretty far aft. That's gotta figure out to about a 200 mile plus range. Judging by how you've done the rest of your projects I'm sure you've thought it out in detail. Just surprised by that much fuel in a 16 in the lower 48.
Norm

Captains Cat · Posted: Fri Mar 10, 2006 11:14 pm Post subject:

Hey Dave, put 40 gallons up in the bow too, then it'll float level and you'll only have to buy gas 2X a year.. Shocked

.. Go for the lows in price periods.... And if you put 6 feet on it, you'll have a 22!!! Rolling Eyes

Just ran the slideshow of your album, what a great looking boat!! Thumbs Up

Charlie

oldgrowth · Posted: Sat Mar 11, 2006 1:32 am Post subject:

When I add 19” to the boat, I will not remove the existing transom. The 19” will be added to it which creates a dead space. The space normally would be wasted space, so I figured I would install the fuel tank there. A 40 gallon tank will fit in the dead space very nicely. I would not necessarily run around with 40 gallons all the time. I carry 20 gallons with me now and am always running out. With 40 gallons I should have a range of 250 miles.

The 19” added length will add 337 lb carrying capacity, less the weight of the extension. Full fuel will weigh 260 lbs plus plastic fuel tank. The remainder of the dead space will be filled with Styrofoam for flotation. Theoretical with the extension, the weight of everything else will be shifted forward (center of gravity shifted back), so my balance should not change much. If anything it should balance the boat better and side to side balance will not change as I use fuel.

My existing engine well will be extended up 4” and enclosed for dry storage with cushions on top, for a sun perch for Terri. I added an updated sketch of what my boat will look like to my Boat Projects album.

As I get experience with my boat, my goal is to put in, in Olympia and go to Lewiston, Idaho.

Norm S · Posted: Sat Mar 11, 2006 2:16 am Post subject:

Dave, Like I said above I had no doubt that you had it all figured out. It makes perfect sense. Just kinda surprised me with that amount. I had been planning on going with 20 gals. That is how my boat was originally equiped and I figured with the lower fuel burn of the new motor I'd be fine. Maybe I'd better rethink.
Norm

dogon dory · Last edited by dogon dory on Mon Mar 03, 2008 9:35 pm; edited 1 time in total

Sorry, Folks - Post Deleted By Author

CAVU · Posted: Sat Mar 11, 2006 12:34 pm Post subject:

Dave,
I know this thread is about gas tanks, but I was surprised by your last statement about going from Olympia to Lewiston. That is a long haul on the outside. What are your planned stops? That plan would make a very interesting, at least to me, thread. Care to elaborate?

oldgrowth · Posted: Sun Mar 12, 2006 4:45 am Post subject:

Ken - instead of hi-jacking this thread, I started a new one to answer your questions. It is here Olympia to Lewiston trip