Black tar material on fuel tanks

[Kauaiman]

I am looking at purchasing a 1974 GB 32. The owner has done a great job maintaining the boat. You could eat off the Lehman engine. My only concern is there is some black tar material on the fuel tanks. Was this standard procedure coming out of the yard? I don’t see any rust, but on the port tank there are some black spots in one corner closest to the engine. I’m having a survey done, maybe he can explain. Any thoughts or advice on this matter would be appreciated. I can take a few photos,but new to this site and don’t know how to load them here. Thanks for any input!

 

[Marco Flamingo]

I had an older boat (1960's era) that had a tar or creosote coating on the fuel tanks. Most of the Taiwan trawlers had fiberglass over the tanks. I think the tar is actually better. Fiberglass can break free of the tank and water gets between it and the tank and cause pin holes. I don't think that can happen with tar. Mine never proved to be messy. Why use fiberglass when tar is quicker and cheaper? Probably because it can be easily painted and appeal to first time boat purchasers.

 

[GoneDiving]

Is it black or very dark brown? I'm guessing your tanks are glass??

If dark brown on steel it may be lanolin oil. Used as a very good rust protector on steel. It is VERY good at this but an absolute biatch to remove after any length of time. It's so good it may have been on there for decades. I've had 2 guys working continuously for a week to remove it of my 54 footer mid refit.

It works very well but sell the boat before you have to remove it again. ?

 

[Keysdisease]

A common tank coating in that era was coal tar epoxy. Is the finish hard?
This is still a very good tank coating today. The common marine supplier for this was International Paint which has plants all over the world including the several on the Pacific rim.

 

[ofer]

A common tank coating in that era was coal tar epoxy. Is the finish hard?

love that stuff

 

[Kauaiman]

Thanks for the responses. I am going to the boat tomorrow and will try wiping the tanks and see if it is a tar product or some type of sealer.

 

[Sailor of Fortune]

love that stuff

I agree!

 

[Mike GB32]

I was in the engine room of my '74 GB 32 (#523) today. No black tar on the tanks.
Look for rust or repairs at the filler neck. Its a common area for water intrusion from leaking deck filler seal.

 

[Kauaiman]

Update. I had a survey done and he really didn't know what the black spots on the lower tank was. I received an email from another GB 32 owner that said his tanks did not have any of the black spots. The seller is asking $60,000 which I think is too high for a boat with 40 plus years with original steel fuel tanks. I will be continuing my search for another trawler. Thanks for the advice from everyone.