Fuel Tank Size

[bobfish21]

Not sure if I'm in the right category here. Coming home from a late night fishing trip on my '74 23 Tsunami, 260 efi/ alpha 1 I/O, ran out of fuel 100yds from my slip. Put 10 gal. in to get me to the fuel dock, filled tank and it only took 43 gal. Was under the impression I had a 72 gal. tank, but the numbers tell me more like 55. Boat has the fishbox/ livewell setup immediately aft of the fuel tank, which is original but in good shape. Can Anyone with any experience with this model tell me what size tank is in the boat? Concerned that maybe I have fuel pickup issues. Also, if I opt to install more fuel capacity in the near future, is there room for a larger tank, or will i have to add a second aux. one? Thanks for any advise!

[Bushwacker]

In a boat that age, it's very possible that the original tank was replaced, even though SeaCraft never foamed in the tanks at the factory, which allows them to last MUCH longer, without wet foam holding saltwater against the tank. Replacement tank may have been smaller than original. Some 23 Sceptre/Tsunami's had 105 gallon tanks when new, although they may not have had the fishbox you mention. A second smaller tank might be a good option if you burn E-10 gas because it's best to have tank either completely full or empty with that stuff to minimize condensation, water build up and phase separation, especially if you have to mothball the boat in winter.

[77SceptreOB]

Originally Posted by Bushwacker

....even though SeaCraft never foamed in the tanks at the factory, which allows them to last MUCH longer, without wet foam holding saltwater against the tank.

Not true. We bought our 1977 SeaCraft Sceptre 23' brand new and it certainly had a "foamed in" fuel tank. In fact, when I had to replace the original tank 2 years ago, I had to break it loose from the foam and it was a PITA. The corrosion from where the water was trapped between the tank and foam was the reason for the failure. Very pitted and corroded, but just in that area, otherwise the tank was in good shape. Moral of the story....DON'T FOAM IN THE FUEL TANK, even though SeaCraft did in SOME years...

[bigeasy1]

As an owner of a 1974 23 Tsunami with an I/O Alpha drive,I can tell you that the fuel tank(original one) in my boat is 55 Gallons.The tank was screwed in by four angle brackets that are welded to each side of the tank,about 3 or 4 inches in from the corners.
There was only a tiny bit of foam holding it in
The tank is clearly marked with the 0.125 thickness,and capacity of 55 Gallons. I forget the manufacturer,but it was made in Hialeah Florida.
Looking from the stern forward,I have the I/O engine box,then the in deck fish/bait box,then the tank,then the long in deck storage compartment,that runs into the cabin.

This was the original setup in this boat as verified by the three previous owners.The original specs show the I/O listed with a 72 gallon tank,but it was not the case with mine.I assume they offered a few tank and hatch versions.

[bobfish21]

Big Easy, sounds like you and I have the same model, 55gal is in line with what I come up with(10 gal emergency fill, 43 gal top off at fuel dock). Thanks for the help!

[bigeasy1]

Bobfish,
Looks like we have the same boats and the same powerplants.

Where abouts in L.I are you?,My son lives in Sayville.I'm trying to talk him into getting a boat,naturally a Seacraft.It may be a losing battle however,with a two year old and another possibly on the way.
I keep telling him that my grandson deserves a Seacraft.His wife has a different opinion however.

I would think that you could lengthen the fuel compartment by extending it forward,and possibly a bit rearward eliminating the fish /bait box,allowing for a bigger tank.An easier way may be to put in a small secondary tank just forward of the current tank.
Sometimes I wish I had more fuel capacity,as the fuel dock at the marina gets crowded,and the wait can be long.I don't normally have any fuel shortage problems,but if I have to make15 to 20 mile runs one way to get to fish,I have to fuel up every day,which I'd prefer not to.

Maybe some of the resident experts on here can help tell us what would be involved in installing a secondary tank.Not sure what would be involved in switching valves or fill and vent lines.

[bobfish21]

Big Easy, I'm 1 town over, less than 10 min. west of Sayville.lIf your son wants to test run a 23 tsunami, 260 efi alpha1gen2, give me a heads up. Boat is a '74, repowered in 2000 along with new transom, engine beds.

[gss036]

My 1989 23WA Seacraft had a 115 tank and it was foamed in at that time. I developed a leak in the rear bottom portion which was not foamed in. I replaced the tank with a 75 gallon tank. It is foamed and screwed in with welded on brackets. I now have 225 hp Honda which gets twice, maybe more mileage than the old Mercury 2 strocker. I had it made locally. The original tank did not have any corrosion on the sides of the tank, but 2 out of 4 brackets were loose when I removed the old tank. Even removing both deck panels, I still had to cut the tank to get it out of the hull.

[Water Rat]

I Have a
1978 23' Sceptre with a 7.4 liter Bravo One. My boat did not have the small in-deck live well forward of the engine compartment and came from the factory with what I remember to be a 72 or 80 gallon aluminum tank that was installed with some foam on the sides between tank and stringers.

At about the twenty-odd year mark, I decided to replace the tank (which to my amazement had not sprung any leaks yet). I needed more range and finally decided to go with two tanks. My aft tank, immediately in front of the engine compartment, holds 65 gallons; the forward tank, approx. 45 gallons, which I had fabricated in an odd shape to take-up a small porton of the fish box but also extends forward and underneath the fish box. This configuration allowed for aprox. 20 extra gallons without consuming too much of the fish box.

I typically run off the foward tank first, then know exactly what I have left to get home - makes fuel management fairly simple. It took a bit of engineering to get the right dimensions and configuration for the forward tank; believe I still have the drawings if anyone might have a use for them or wants to recreate what I did.

[Water Rat]

I Have a
1978 23' Sceptre with a 7.4 liter Bravo One. My boat did not have the small in-deck live well forward of the engine compartment and came from the factory with what I remember to be a 72 or 80 gallon aluminum tank that was installed with some foam on the sides between tank and stringers.

At about the twenty-odd year mark, I decided to replace the tank (which to my amazement had not sprung any leaks yet). I needed more range and finally decided to go with two tanks. My aft tank, immediately in front of the engine compartment, holds 65 gallons; the forward tank, approx. 45 gallons, which I had fabricated in an odd shape to take-up a small porton of the fish box but also extends forward and underneath the fish box. This configuration allowed for aprox. 20 extra gallons without consuming too much of the fish box.

I typically run off the foward tank first, then know exactly what I have left to get home - makes fuel management fairly simple. It took a bit of engineering to get the right dimensions and configuration for the forward tank; believe I still have the drawings if anyone might have a use for them or wants to recreate what I did.