Boat gas tank on roof?

[HenryKrinkle]

http://i91.photobucket.com/albums/k319/billsam556/boattank2.jpg

Good, one test is worth a thousand theories. Got a link to the tank?

Let us know how it goes. Good luck.

Al

I think it's a 12 gal. (36x18x7") A couple google searches make me think these have baffles inside, but I asked the guy to check for me. That would make me more comfortable putting it on the roof. Here are the pics he took:

 

[bloc]

My concern is that a mere 30lb of dynamic weight up top just may be comparable to 100lb (or more?) of static weight, in terms of the forces your rack will see when driving. A simple comparison would be the 200lb weight that will exert thousands of "pounds" of force on the rope that has to catch it when said weight is dropped. Obviously we are talking different velocities, but the point is without knowing what those forces are, you are taking a risk.

Keep in mind that I'm talking about Force, not Weight.

With baffles though.. you should be good to go.

 

[DirtRoads]

A friend of mine has a 1971 scout and he uses this method. It was out of necessity after his gas tank acquired a hole out in the middle of nowhere. So, he took his ~8 gallon fuel tank from his boat, strapped it to the roof and ran a gravity fuel line straight to the carb on the engine :smiley_drive:. No problems to speak of.

The only difference is that his truck is only driven on the pavement during maybe 10% of its travels. By all means, give it a shot.

 

[alexrex20]

this is what your friend told you, or you were there and witnessed it? there's no way gravity-fed fuel had enough psi behind it to power that V8.

 

[Brian McVickers]

this is what your friend told you, or you were there and witnessed it? there's no way gravity-fed fuel had enough psi behind it to power that V8.

Why would you assume that his friend is lying to him?

Also consider that since '71 the original V8 could now be something else.

 

[Brian McVickers]

Well, it seems some people think it's a really bad idea. The tank I'm looking at is 36x18x7. It's not really that big; as long as I can attach it well I don't think it would be a big deal. It's not something I'd use everyday. I'm thinking I'd make the mounting setup and then just keep it all in the garage until I need it.

How many people run overbuilt steel racks with tents, jerry cans, spare tires, etc. up there?


I could just get jerry cans, but then they'd have to be stored upright which means they'll probably have to go into a special mounting bracket on the rear bumper= expensive. Also, I wouldn't want fuel permanently attached to the most likely place of getting hit (large metro. area).

So for $40 I'm going to give it a shot. Once I get it mounted and full I'll take it for a spin, if it seems dangerous I'll go for something else. I guess I'll keep you posted...

Jerry cans do not need to be stored upright. Well, it depends on the type of jerry but if they don't leak then you are fine. Wedcos with the lever style closure can be stored upright, on their long side or on thier flat broad side.

Ideally your boat tank will have baffles, some of the better ones do.

 

[R_Lefebvre]

And, the baffles only really matter if the tank is partially full. If it's full, or if it's empty, it won't make a lick of difference. So, if you fill it right up, then wait until your main tank is empty and transfer ALL the fuel, there will be no sloshing. A full fuel tank, will NOT slosh, even without baffles.

 

[HenryKrinkle]

Thanks for the tips guys. I also just found a nice looking rack meant for a trailer hitch. I'll use it as intended until I can spring for some gutter mounts. Will try to get some pictures and a report after I test it all out.

 

[granitex1]

I have run a plastic marine can on my roof for several years, It is not up there all of the time but for longer runs where there are not so many gas stations around it is a great solution for me.

I know that it is not the best pic but you get the idea.

 

[dbreid]

My thoughts on fuel...

I have done several combinations of all of the things described here on my Rock Crawler.

I have a 454 engine in my Offroader, and it devours fuel. And I have done many LONG trails (Dusy Ershim, for example) that are very fuel intensive, so fuel is always a concern. Some things I have tried (no real order)

1.) I agree strongly with low COG. Don't dicount this. I guess if you aren't actually offroading, who cares, but for me, I go to great lengths to keep things low. I sliced up the body to keep clearance on 40" tires with only 4" lift. I mount spare driveshafts and tools as low as I can (often underneath, shielded by the frame). This is a big deal for me. Rollovers are a hassle.

2.) I run twin factory 20 gallon tanks (one on each side). Saddle tanks, with a switcher from the dash. I like this because I can drain fuel from one, then the other at intervals, so I keep weight even, and have less trouble if I punch a hole in one. Then I only lose half my fuel. Also important if I am rolled on my side... I can swap tanks, and drink from the one with the most fuel hitting the pickup.

3.) I have tried a combination of Jerry Cans, RotoPax, and Boat fuel cans. I used to use a 12 gallon AUX fuel tank I got from a boat supply place, mounted flat to the bed. I didn't connect it to anything, but I used the sihpon to refule the main tanks at lunch breaks, etc. As I said, I am all about keeping fuel in the main tanks, and not having slosh or High COG.

4.) I LOVE RotoPax. They are great, beause they are easy to mount other places. I have some mounted flat in my truck now, and they carry enough AUX fuel to refill quite a bit. I do not like the idea of only having a huge interconnected fuel system, because it makes it hard to share fuel with others. I almost always wheel with others, and lots of time you need to share. Having small, portable fuel cans is definitely the way to go. One of the main reasons I ditched the 12 gallon boat thing. Too heavy and hard to move around.

5.) One last thing I do is use a collapsible fuel bladder (like one of those collapsible water jugs). I fill it up (or a few of them) whenever the "last gas" is before getting to the trail, then I top up as soon as I get to the trailhead and air down. I do not like the idea of carrying unvented fuel in an unapproved container for long distances, but I do it on the road right before I get to the trail. Again, my whole plan is to refill the facotry tanks.

Hope this helps.

-Dan

 

[alexrex20]

Why would you assume that his friend is lying to him?

Also consider that since '71 the original V8 could now be something else.

there is no way that gravity-fed fuel will EVER have enough psi behind it to run ANY carburetor on ANY engine.

even if the original V8 were something else, he said it has a carb. so who is lying? DirtRoads or his friend?

 

[Mr. Leary]

there is no way that gravity-fed fuel will EVER have enough psi behind it to run ANY carburetor on ANY engine.

even if the original V8 were something else, he said it has a carb. so who is lying? DirtRoads or his friend?

My weed eater can run on gravity fed gas... :wings:

 

[User_Name]

there is no way that gravity-fed fuel will EVER have enough psi behind it to run ANY carburetor on ANY engine.

even if the original V8 were something else, he said it has a carb. so who is lying? DirtRoads or his friend?

I disagree because I have done it
Had a 79 Toyota 4wd pickup with a 20R that was my construction truck and was having fuel problems (turned out to be the little duckbilled screen on the fuel pump intake had fallen off and dirt clogged the ball bearing for the fuel bypass)
Anyways I was only 3 miles from home when the truck sputtered to a stop, it would fire and idle but couldn't get any RPM out of it without it dying.

In my toolbox I had a peanut can with a brass union brazed in the side of it with 20 feet of clear vinyl hose that I used as a water level for work.
I pulled the fuel line from the carb and attached the hose to it, wedged a 20 penny nail between the hood and the fender so as not to pinch the hose then filled the peanut can with gas from the can I carried in the back for the nail gun compressor, used a bungie cord to strap the can down on the ladder rack.

That setup was enough for me to limp the 3 miles home so I could work on the truck.

My crew made lots of jokes about how many miles too the peanut can does that Toyota get

 

[NId4x4]

Perhaps he simply mispoke, and the roof mounted tank feeds the factory pump and not the carb. simple mistake.

 

[DirtRoads]

this is what your friend told you, or you were there and witnessed it? there's no way gravity-fed fuel had enough psi behind it to power that V8.

I saw it. I want to say it doesn't have an 8 cylinder engine, but I honestly don't know. You have to remember, it doesn't see any kind of high rpm as the truck goes 8 miles down an old back road at a really low speed before getting in the dirt.

I would get some pictures if he hadn't repaired the tank and disassembled that rig.