Gas tank construction 1988 Donzi 18'

[wwahl]

After replacing two different gas tanks in two different Donzi 16 foot boats (1966 & 1970) I am very wary about this issue. My present boat is a 1988 18'. What is this 42 gallon tank made out of and what is its normal life span?

[HallJ]

After replacing two different gas tanks in two different Donzi 16 foot boats (1966 & 1970) I am very wary about this issue. My present boat is a 1988 18'. What is this 42 gallon tank made out of and what is its normal life span?

My '88 tank is made from 5052. It in great shape inside and out. It depends on how well the drain pipe was sealed under the tank and between the bulkheads.

Remember, these boats were built in an open air shed by cheap labor and poor production supervision.
Don't expect too much.

It can be hard to know how well they were built until you cut one apart.

Jeff

[Tidbart]

Should be aluminum. Look under the inspection plate, you should be able to see the sender and the end of the tank. You should also be able to get some nameplate info from the tank.

As far as longevity, an aluminum tank should last 30 years or longer, I would think. There are other factors that may effect it, environment, fuel, quality of build, things like that.

B

[Morgan's Cloud]

Has the boat had a life in a salty, humid environment ?

[Tidbart]

My '88 tank is made from 5052. It in great shape inside and out. It depends on how well the drain pipe was sealed under the tank and between the bulkheads.

Remember, these boats were built in an open air shed by cheap labor and poor production supervision.
Don't expect too much.

It can be hard to know how well they were built until you cut one apart.

Jeff

That tank company is now RDS, good company. Model number is now 54412. Just in case you need to know some day.

B

[wwahl]

Has the boat had a life in a salty, humid environment ?

Strictly fresh water and stored in a heated location during the off season.

[mattyboy]

If the tank is untreated alum and foamed in the expected life span is about ten years. By untreated means no protective covering like epoxy paint
They do last longer under good care and maint but need constant inspection

[smidgen too]

My 1974 Donzi Doral has the original aluminum fuel tank that looks great. After rebuilding the transom I have found that the fuel tank might be the only thing that was well built & lasting all these years.

[boatnut]

My 1974 Donzi Doral has the original aluminum fuel tank that looks great. After rebuilding the transom I have found that the fuel tank might be the only thing that was well built & lasting all these years.

From my understanding, looks great is meaningless on this topic. The issue is crevice corrosion which is caused (on aluminum, or stainless, etc.) by moisture getting to the metal without enough oxygen. The areas of a tank that you can see are getting enough oxygen so they should not show corrosion. The area lower on the tank that has moisture (with little or no air) between the foam and the metal will be where the problem exists. And unfortunately as has been mentioned I don't think you can chk the condition of the tank without removing it. We (my son and I) have a '69 18 we are starting to work on and we have a perfect performing and looking steel tank that has been in the foam for 44 years. Changing it is a tough decision but probably the correct one.