Adding auxilliary Fuel Tank to 280DA

R

roger275

Member
Jun 24, 2009
94
TX Gulf Coast
Boat Info
380 Sundancer 2003 (Sold)
280 Sundancer
Engines
4.3 Liter MPI Mercruisers with Alpha 1
Has anyone added an auxilliary fuel tank to the 280DA? I really need 30-50 gallons more fuel and wonder if anyone had shoe horned a tank in anywhere. I already know about bigger boats having bigger tanks and longer range.
 
roger275 said:
Has anyone added an auxilliary fuel tank to the 280DA? I really need 30-50 gallons more fuel and wonder if anyone had shoe horned a tank in anywhere. I already know about bigger boats having bigger tanks and longer range.
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If you do not have a generator you could slide the fresh water tank all the way to one side of the shelf in the engine compartment then add a second 28 gallon tank there.

Figuring out how to utilize the fuel in this tank is something I’ll let you figure out.
 
Are you looking to permanently install additional tankage or is this for occasional or one time use?

For occasional use, I’m not sure about for gasoline, but for diesel there are flexible fuel bladders that can be easily stowed when not in use. For single use, a 55 gallon steel or plastic drum would work.

The main problem in either case, as Presentation asks is: how are you going to use this fuel? You will most likely need a transfer pump. Not sure about the layout on your 280, but the issue with many Sea Rays is that the fuel fills are outboard and doing a transfer via the main tank fills underway requires crew to be on the side deck or swim step in a sea way – with the fuel tanks open to possible sea water flooding. Permanently plumbing inside the boat is probably safer, but again goes back to how often you need the extra fuel.

Getting back to my first question, if you need the extra fuel all the time, then perhaps you are using the boat in a way the designers did not intend. Maybe it’s time for a new boat that more closely matches your intended use.
 
I think a permanent install would be easiest. I'm not familiar with the 280da ER. If the additional tank fits as sugested then the fill hose can be attached to main tank fill hose via a "Y" fitting. A manuel valve could be placed at the tank to bypass the auxilary tank as an option.

Now let's make the auxilary fuel usable. This hose should be fitted to the bottom of the auxilary tank and attached to "T" fitting at main fuel fill hose. Add an inline fuel pump to that hose. Add a switch at the helm for this pump.

The other option is to copy a pickup duel tank setup.
 
Sea Gull said:
Getting back to my first question, if you need the extra fuel all the time, then perhaps you are using the boat in a way the designers did not intend. Maybe it’s time for a new boat that more closely matches your intended use.
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Across many 280 owners the fuel capacity is probably the #1 complaint (take that for what it is). However changing the fuel system, and adding an additional tank is going to co$t (doing it correctly), along with some unknowns that may not be so favorable. You have to consider the additional weight along with an unbalanced ballast. The only space, as Presentation points out, is next to the water tank. I would be afraid of changing the boat, possibly causing a listing problem.

You are asking for people that have done this already...likely not done. I'm seconding with Sea Gull that if this is a necessity, the best move is a different model (Sea Ray of course :thumbsup:)
 
:smt001 what range are you looking for:smt001
roger275 said:
Has anyone added an auxilliary fuel tank to the 280DA? I really need 30-50 gallons more fuel and wonder if anyone had shoe horned a tank in anywhere. I already know about bigger boats having bigger tanks and longer range.
Click to expand...
 
Hey, the 290 has ~30 more gallons of fuel. Not much bigger of boat but the fuel you want. I agree that the extra fuel onboard may cause a whole new set of problems.
 
If you are already bitching about the range of the 280, adding 28 gallons is not going to give you much relief. Not to mention the hassle of filling it up and then delivering it back to the main tank. You're better off balancing the boat, running it at it's optimum efficiency and getting familiar with where some good fuel stops are. I boat according to my range with the 280. I can hit about 100 miles comfortably and that's how I plan my stops. 100 miles, slip, explore, sleep, fuel up, 100 miles.

I've come to the realization that it's this way with the 280. I won't be happy until I have 400 gallons of capacity.
 
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I guess this means you didn't add one. We're taking an ICW trip and there's at least one crossing where 100 miles won't quite get it done but 130 will.
 
OK. So for one day out of the year you have two basic options. 1) Buy a bladder tank, 55 gallon drum or a bunch 5 gallon gas cans and refuel as necessary. 2) Go slow. Do all or some portion of the 130 mile run at idle speed to conserve fuel.

Both are done all the time on larger diesel boats when doing long distance deliveries. At normal cruise my boat has a range of 250 miles. At 10 knots range increases to 550 miles. A 100 gallon fuel bladder increases my range to 650 miles (hello Bermuda!)
 
If it's a one-time (or rare) situation go with a half-dozen five gallon cans as Sea Gull suggested.
It is "doable" to add another tank, but the trouble and expense to add only 28 gallons isn't worth it.

You'd need to build a fuel manifold-common on larger twin engine boats with dual saddle tanks. A series of valves selects which tank each engine draw its fuel. If you have fuel return lines for your EFI engines (as with diesel), the manifold must also include valving for those as well.

For 28 gallons or so, all that just ain't worth it...if you can fit a larger tank, and need the range more often, go for it.
 
I don't know the floor plan of the 28'
But I put a 70 gal belly tank in the aftcabin under the bunk.
Added a 2nd filler for the Aux tank and fuel feed is plumbed to the engine.
 
Tail Chaser 661 said:
I don't know the floor plan of the 28'
But I put a 70 gal belly tank in the aftcabin under the bunk.
Added a 2nd filler for the Aux tank and fuel feed is plumbed to the engine.
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To each their own, but I wouldn't do this.
Installing a fuel tank in a living space aboard a boat is not only unsafe, it is a violation of CG regs.
 
My fuel tank is 80% under the aft cabin. I beleive taill chaser added his tank in this area of the bilge. Storing fuel in the cabin is insane, I agree.
 
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No stored fuel. Custom tank built to fit contour of boats V bottom and sides Tanks below aftcabin extending 15" into the bilge. 60"L x 22" W. Completely glassed in with marine ply and epoxy resin.

I had the tank builder come out and confirm all measurements. If something wasn't right. I'm sure he would have pointed it out. He's been in business building marine tanks for 20 years. This guy does just about all boats and yachts in So Calif.

I'm already sleeping next to a 100 gal factory tank with a plywood bulkhead as a divider. Doesn't really matter. If either tank blows, Your fish chum anyway.
 
Henry Boyd said:
The only thing that separates the mid berth on the 280 and the gas tank is a sheet of plywood. Well not completely because the plastic acess plate is under the middle berth cushion.

Henry
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So as the tank starts to blow. The plastic access plate pops first, Making for a real nice blow torch. :grin:

I think going out with a bang would be less painful :smt043
 
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