Fuel Tank Relocation

[97Aero]

I have a G3 1860 CCJ with a Yamaha F90J. To me the boat seems very tail heavy. I was thinking about relocating the fuel cell to the forward deck where there are two stowage hatches. I have made the measurements under those compartments and even with the fuel cell located between the two hatches I think I will still end up with just about as much storage left and right of the tank if I make a small sub floor up there.

Install seems straightforward and will plumb the tank filler/vent above the deck. Anything else I must consider. Will pulling the fuel an extra 11 feet be an issue? Think it may be a way to get 90 lbs off the *** of the boat and level it out a bit.

Thanks

 

[Kevin Turner]

97Aero » Yesterday, 19:00[/url]"]I have a G3 1860 CCJ with a Yamaha F90J. To me the boat seems very tail heavy. I was thinking about relocating the fuel cell to the forward deck where there are
Install seems straightforward and will plumb the tank filler/vent above the deck. Anything else I must consider. Will pulling the fuel an extra 11 feet be an issue? Think it may be a way to get 90 lbs off the *** of the boat and level it out a bit.

Keep in mind I do not have knowledge of your exact craft. However, your reasoning seems sound. On a side note, where are your TM batts located? If in the stern, I'd suggest relocating batts would be easier than the fuel cell.

On to your question: Pulling the fuel an additional 11' should be of little concern / consider when when filling a stationary fuel cell, USCG requires spillage must not enter the craft / be sure to safely vent the area where the fuel cell is to be relocated /

 

[RiverBottomOutdoors]

Could hurt performance . Too much forward weight will make the boat push water instead of planing off. I would leave it like it is. I have the 1656 CCJ.

 

[97Aero]

RiverBottomOutdoors » 20 May 2014, 13:17[/url]"]Could hurt performance . Too much forward weight will make the boat push water instead of planing off. I would leave it like it is. I have the 1656 CCJ.

Thanks for the sanity check. Think next time out I am going to drain the aft tank down to min fuel and throw a 80 lb bag of Sakrete or Sand up in the approximate location see how that changes performance/stance. Should be a decent check. I have noted on the G3 1756 models they put the tanks up front.

 

[dhoganjr]

Thanks for the sanity check. Think next time out I am going to drain the aft tank down to min fuel and throw a 80 lb bag of Sakrete or Sand up in the approximate location see how that changes performance/stance. Should be a decent check. I have noted on the G3 1756 models they put the tanks up front.

I was thinking about this earlier and was going to suggest using something equal to the weight for a trial run before you do all of the work. Sounds like you have it under control, let us know how it works.

 

[97Aero]

dhoganjr » 20 May 2014, 18:42[/url]"]

Thanks for the sanity check. Think next time out I am going to drain the aft tank down to min fuel and throw a 80 lb bag of Sakrete or Sand up in the approximate location see how that changes performance/stance. Should be a decent check. I have noted on the G3 1756 models they put the tanks up front.

I was thinking about this earlier and was going to suggest using something equal to the weight for a trial run before you do all of the work. Sounds like you have it under control, let us know how it works.

I hope so. Does not seem to have a problem getting on plane now with somebody (170+ lbs) sitting forward of the console. We'll see how much I adding the extra weight levels it out.

 

[dhoganjr]

Just a guess but the motor weight is around 380 plus starting battery in the back, about 450 pounds in the rear. It may be about right with the tank up front. I would still check it to make sure, with just a few gallons of fuel. I've never ran one with fuel lines that long, maybe someone else can chime in, but I would make sure the primer bulb is firm each time you start it. May not be an issue, but it would keep an adequate supply to the fuel pump, less strain on it I would think.

 

[dhoganjr]

I have the trolling motor and 2 group 27 batteries up front that helps level it a bit with all the weight in the back. Motor weighs 505 and 2 12 gallon tanks and starting battery in back. Mines an 1860 Alweld.

 

[RiverBottomOutdoors]

What makes you think the boat is tail heavy?

 

[97Aero]

RiverBottomOutdoors » 20 May 2014, 20:04[/url]"]What makes you think the boat is tail heavy?

Suppose thats a subjective thing I suppose. First lets talk about what I have upfront. 75 lb thrust Motoguide with a beefy swing mount, a 22 lb anchor with anchor winch, under the console I have two Group 29 TM batts as well as a Minnkota 3 bank charger. Figured all that would level out the boat a bit and it probably has to some extent but the stance of the boat still seems *** heavy. Absolutely love the boat no doubt about that, have heard other people also comment on the stance of the 1860 as well. What I can tell in my limited experience with boats is that it does feel more responsive on a lighter tank. Thats probably normal with any boat though. Dunno maybe I am just being stupid....

But I do have one question for you since you have a G3 as well. How much play do you have in your steering either unloaded on the trailer or in the water before your motor starts to respond? I have approx. From dead center I can move my steering wheel about 10 degrees before the motor starts to respond. My first jet so I am not sure how responsive they should be.

Thanks

 

[RiverBottomOutdoors]

A little play in the steering linkage is normal.

Lighter is always better for an outboard jet. It has one advantage: running shallow. And one huge disadvantage: efficiency. It burns more fuel, it's slower, suffers greater performance loss in current, wind, and under heavy load.

Post some pics of your ride. We like pictures on here. ;-)

 

[97Aero]

RiverBottomOutdoors » 21 May 2014, 15:57[/url]"]A little play in the steering linkage is normal.

Lighter is always better for an outboard jet. It has one advantage: running shallow. And one huge disadvantage: efficiency. It burns more fuel, it's slower, suffers greater performance loss in current, wind, and under heavy load.

Post some pics of your ride. We like pictures on here. ;-)

Picked it up last fall. 2006 model with 83 hrs on the clock. Just finished the 100 hour service this weekend. It is a lot of fun no doubt.

 

[RiverBottomOutdoors]

She's a beaut! Honestly, I would not bother putting money/time/effort into moving the fuel tank. This hull works. If it didn't, they would change it. You say it planes off good, so there is little, if anything, to gain by moving the tank.

 

[dearl]

Another option, and probably cheaper, add a set of float pods to it. I have had 2 different sets and both made my boat perform better. A properly engineered set of pods can easily displace more than half the motor weight. My pods were designed for 1.5 cubic ft of air. 1 cubic ft of air will support over 63 lbs. My 90/65 2 banger weighs 318 lbs but really my pods are supporting over half that weight. My rig has a tunnel and still only displaces 5" at rest loaded. I do have over 300 lbs of gear/bait tank/batteries on or under the front deck, but she's nose up when you hit the gas, and planes out in no time.

 

[PSG-1]

My Triton 1650SC was also very stern heavy, especially considering that I had the factory tank, AND another 12 gallon tank back there, as well as a group 24, and group 27 batteries.

I ended up modifying the front deck of that boat, and moving the 12 gallon factory tank, and 1 of my batteries forward. I would have moved more weight to the front, except, I am operating in coastal waters, where there are waves, and large boats that throw a 3 foot wake. Too much weight on the bow equals being sunk. Also, in the winter time I use this boat for commercial oyster harvesting, and again, we tend to stack a lot of weight on the bow.

Here's a link to the thread, showing how I modified the boat and moved weight forward:

https://www.tinboats.net/forum/viewtopic.php?f=21&t=24987

 

[97Aero]

Great advise on here from everyone. The Engineer/Mechanic is me wants to do this. I opened up the front hatches and took out the liners and there is a lot of room up there. Actually a lot of wasted space considering the way the liners sit. As Jonah said previously these jets defiantly drink the gas so I am leaning toward having the best of both worlds, two tanks. Have one up front for running the rivers around here where the water is skinny and the aft one for reserve when going on extended lake trips to eliminate fill ups. I am defiantly going to test this theory out with some dead weight up front to see if it does flatten it out any or changes the handling characteristics before I start bending metal for tank mounting. Found a $12 gal Moeller tank for $150 that would fit the bill nicely as far as dimensions. We'll see how it goes and will post lots of pics of the install. I am fortunate to work for a Aircraft modification company so theres plenty of scrap tin around and tools to bend it with.

Thanks

 

[PSG-1]

Yeah, you'll be surprised how much difference it will make by simply moving as little as 50 lbs (the weight of a group 24 battery) to the bow, much less the weight of a fuel tank and other gear.

 

[smackdaddy53]

Have you considered bolt on or weld on pods to offset the weight of the motor? It would be worth looking at.

 

[97Aero]

Started the forward tank install yesterday. Got the tank cradle out of the way. It was a tight squeeze but I was able to get the structure complete. Decided to suspend it between two bulkheads and it came out pretty well. Next steps will be the above deck filler/vent and plumbing it back to a tank selector valve. Plenty of room left/right of the tank for storage and I will build a close that out with a some metal as well.

 

[97Aero]

Finished my tank relocation project. What the hell else are you gonna do in this weather. Closed out the sides of the tank to keep storage. Hopefully it will level out the G3 just a bit to avoid a rock or two.