Grumman 13-needs cleaning


Just picked up a used Grumman 1340-C, (built in 1979) from the original owner. He had all the paperwork and never even sent in the warranty card! (I’m going to send it in and see what happens)!

Anyway, had it in my pool last night, I love how light it is, and its initial stability is great. However, I did push the envelope and dumped it by leaning way over and to the rear. I’m going take her out this week.

My question is as to sprucing it up. It’s a little rough looking, oxidized, stained, etc. What’s the best way to clean it up, and maybe put a coat of wax or polish on it. Any suggestions for products to use? Also, has anyone ever painted one?


Try using an automotive detiregent . if that doesn’t work I would use comet or compound.

this is my opinion, I only did it once to an aluminum I had borrowed.

Lean the boat over not you!
Keep your head in the gunwales. The boat has good secondary stability too but you have to keep your head in the boat!

I have never cleaned my Grummans and they are all oxidized…so cannot be of any help there. Yes they can be painted…but paint adds weight.

there are a number of brand names …

– Last Updated: Oct-11-10 11:24 PM EST –

..... for specialty aluminum cleaners available ... many are targeted towards pontoon boat owners (aluminum pontoons) .

There used to be a product called Naval Jelly ... it came in one type for aluminum (oxidation) , another for steel (rust) , and another for porcelain (tubs,toilets,etc.) ... the aluminum one did a great job on aluminum .

Here is an example of a so called specialty marine aluminum cleaner called "Alumabrite" ,

3M also makes one ... I think West Marine sells it plus some other brands .

I'm not certain what actual chemical these products contain ... maybe a phosphoric acid or type there of .

Most people don’t clean them much.
It’s rare to see a well-cleaned aluminum boat, except perhaps boats that have been painted already. You probably shouldn’t even clean it unless you plan to paint it afterward, since the new, clean surface will eventually oxidize again. How many times can you clean off the oxide coating before the hull becomes noticeably thinner? I don’t know.

If you plan to paint it, I’m not sure if cleaning off anything more than just the dirt is necessary.

Aluminum oxide is a very tough material, and therefore not a bad substitute for paint (without the extra weight of paint). I find it a lot more pleasant to look at than a bright “mirror” of fresh aluminum.

It’s your boat, but I just thought I’d add a different perspective.

Grumman 13
Thanks for the advice, everyone! I simply washed it down (it had been stored for 15-20 years) and it looks fine. Well used, but fine. Also, I like the suggestion to keep my head in the gunwales!