Buy a cheap refractor you regard as disposable and can be washed, regularly.
I've tried this before. At the end of my student days I relocated my 12" Newtonian (which had a steel fork and equatorial mount with a polar disk and roller drive) to my mothers place behind Avalon beach in northern Sydney, literally 100 metres from the dunes, with a surf beach on the other side of the dunes.
Even stored in a garage the scope didn't last very long and most of it had to be disposed of after a year apart from the mirrors, which were recoated later when I moved further inland.
Salt air will produce a sticky, salty film on everything very quickly. The film will corrode all the aluminium parts rapidly. This includes the mirror coatings.
The salt will also cause steel parts to rust quickly such as small cap screws, grub screws etc causing them to bind or break. Take a close look at your scope and replace these with stainless steel or brass. In particular this applies to screws around the ring holding the corrector in place, the secondary alignment screws, any screws in the OTA, the screws attaching it to the fork or a dovetail, and screws in the fork and mount. Molybdenum paint (not very attractive) does provide effective protection - I used it on my mount and the fork - except where it is chipped exposing bare metal, that will rust quickly.
There's also another reason why using a good scope in sea air is frankly a waste of time. Basically, the sea produces a lot of fine particulates in the air which have an interesting effect. On one hand the night sky appears incredibly dark, but look carefully and you will realise this is actually because the optical transmission is quite poor - the limiting magnitude is not good.
Edited by luxo II, 04 December 2018 - 05:26 AM.