No 1 is fish oil
On my last fishing boat I also ran a sprinkler type hose through the channels and flushed out every use.

Coat it with Lanotec Steel-Seal. I use it on all skin fittings and motor. It keeps everything like new. You can clean it off with engine degreaser and your trailer will look like new again.
www.lanotec.com.au/product/steel-seal-australia

Karsten said..

twodogs1969 said.. No 1 is fish oil

Does spraying with Fish Oil leave a sticky surface - i.e. when you touch it a week later, is it like wet oil, or a smear of Vaseline, on your skin?

No it dries

keensailor said..
If you have a brand new never been in the water gal trailer would painting it prolong its life. Or any other coating.

Sure, if you have a hot dipped trailer I'd use Industrial Cold Galv paint or if you don't mind a black trailer bitumenous paint like the SCA underbody will seal the zinc and the trailer will outlast the boat. www.supercheapauto.com.au/p/sca-sca-underbody-rust-coating--400g/395325.html
I used it to paint my rear section of the galvanised RHS trailer and kept the rust away for last 6-7 years. For top section I wanted it blue so I used 50% Killrust + 50% Penetrol for initial coat, also no issues after 6-7 years and trailer completely submerged in swamp brine at the local boat ramp.

Thanks for the info gents.

+1 for Tectyl 506. I painted my anchor and chain with it.