I am moving onto a sailboat, which is docked on saltwater. Due to storage limitations, the only place I can store my bike is on deck.

By bike is my main means of transportation - I ride it daily.

What is the best way to prevent rust-damage? A bike cover? Something else in addition to or instead of?

A bike cover will just hold any condensation, would look at rust inhibitors, like Boeshield or ACF-50 (think Aviation corrosion prevention) for inside the frame, keep the rest of the bike well lubed, but accept that you will get rust on hex heads & the steel parts of the drivetrain eventually.

Some brands are worse for corrosion than others, have found that any steel parts on Avid brakes will corrode within a year or so, what ever condition that are kept in, but Shimano steel brake parts kept in exactly the same conditions will stay corrosion free for many years.

For inside the frame I use J. P. Weigle's Frame Saver. Amazon has it.

For the outside of the frame, inspect the bike frequently and use touch-up paint where you see any scratches or paint flaking off.

Good luck! Between my own experiences with salt water ferries (and their fishing boat substitute a couple of times) and wrenching in a shop only an hour away from the Atlantic I will say that rust and other oxidation is inevitably. The first best first step is avoidance. Next is frequent rinsing with fresh water and general cleaning. Third is relubing and waxing (or other protectent). While a tarp might trap moisture If the bikes are above deck and the seas are rough I'd rather ,minimize the drenching that they'll get. Andy.

You might consider pre-emptively replacing plated steel hardware with stainless (corrosion-resistant, actually) steel. I'd suggest using Tef-Gel (https://www.tefgel.com/) on as many dissimilar metal joints as you can; bottom bracket, pedal threads, stem, bar, seatpost and other clamp bolts and so on. It is designed to protect against corrosion in marine environments. I'd suggest using stainless pedal washers also. Framesaver as suggested above or the Amsoil equivalent are highly regarded. There is a new rust-preventive lubricant from the inventor of Tufoil which has gotten good reviews: https://www.hinderrust.com/about-us/ Use stainless shift wires or at least replace galvanized ones with stainless when (not if) they rust. Keep your chain well lubed with a wet-type lube. A good coat of paste wax will help preserve the paint; washing it with fresh water will help flush away salt deposits.

I've just been living in a seaside town, and even there everything became corroded in a few weeks. The humid salty air is enough to rust my steel frame bike on sight. If you keep on top of it you should be Ok ish. Keep the bike rinsed off with fresh water. Do keep it covered on rainy/stormy days, grease and re grease with marine grade grease all threads and mating metal. Then see if you can find a garage to store it away from the sea.
Good luck.

Hmm... I'd be thinking as much SS hardware as possible, and minimum aluminium, all of it well-anodised. And lots of grease.

Preventing Rust on metals includes one main task and that is to keep it clean always. There are many environmental factors that may cause a metal to rust. The easiest method to prevent corrosion of metals is by using a good cleaner that no only cleans the metal surface, but also leaves behind a protective layer that will avoid further corrosion of metals. There are also many more methods to prevent metals from rusting. All of these depend on the environmental conditions and the type of metal being used.

You need a Bridgestone Kabuki Submariner.

Stainless steel tubes. They tried to sell them to boaters. I don't think they sold many.

Cool bike, Grand Bois.

To the OP: I would try and find better storage for your bike, maybe there's someplace at the marina that you could rent for a little $ that's secure indoor storage.

build/buy a deck mounted box , with a watertight seal for the lid, stow a folding bike in it.

Caribbean seawater is Saltier .(some reassurance).



You doing one of those anchor out schemes , or you paying moorage live-aboard rates?


airtight box with a nitrogen purge is perfect. no oxygen, no oxydation ..

Or, more available, anything with a Titanium frame and carbon fork. Salt water has no effect on either.

For the exterior of the bike frame, wash with fresh water then apply an automotive wax.

Store the Surly at a friendly landlubber's house and buy a used Cannondale for < $300. Vintage LL Bean Cannondale as purchased last month for $150.

EDIT: Forgot to say, I'm jealous! Good luck with living aboard! While I am a sailor, living aboard a vintage CC Commander would be cool!

Try a few coats of car wax on the frame and exposed metal (except rims !)
Use a plated chain.
Copper-based anti-sieze should be used on the seatpost and stem.
Sacrificial zinc anodes such as galvanized washers may help locally for particular bolts but unless you dunk the bike in seawater it wont provide total protection.

I vote for a cosmoline dip.

+1 on disassembling and coating the interior surfaces of the frame with a good rust preventative. If you really want to go that far, it is possible to rinse the tubes with mineral spirits and swab out the areas you can reach with some prep solvent or equivalent, let dry and then fog the interior of the tubes with rust converting primer using a long plastic straw. Eastwood makes a variety of products for dealing with existing rust and preventing future rust. Read the descriptions carefully as there are rust converters that must be used on rusted surfaces or they will not adhere, and there are rust converting primers which work as a primer on bare metal but convert any bits of rust stuck in corners or pores/pits into an inert material that will not corrode any further. Make sure your protect the exterior surfaces of the bike with careful masking prior to fogging the inside of the tubes.

Painted surfaces can be protected with a good polymer or polymer/wax blend automotive product. Meguiar's makes some good ones. Chrome should be treated with a good chrome polish/protectant, aluminum with an aluminum product that removes oxidation and protects the surface, and exposed steel with an appropriate lubricant/rust inhibitor.

It's not a bad idea to replace as much hardware as possible with aluminum alloy or stainless steel versions. All of my bottle cage and rack bolts are SS as are all my cables. Carbon fiber is another possibility for some components.

When installing BBs and other parts which are prone to sticking due to corrosion/oxidation/bi-metal reactions, a silicone based grease like Superlube or Park Synthetic is more resistant to water and salt than some other products. It is more expensive, but a $3 tube or $15 tub will last years.

Your greatest weapon is vigilance. Clean and protect/relube frequently and don't let corrosion take hold.

When upgrading your ride, you might want to look at a stainless steel or carbon fiber frame with as many anodized aluminum alloy, carbon fiber, and/or stainless steel components and fittings as possible. You still need to be vigilant as salt air is tough on everything.

Doesn't it encourage galvanic corrosion, which affects both?

There was a product called Protect all . Was a spray on product .it came in liquid ( like armor all ) or airosol can ( the airosol seems to be clearer than the liquid) . I used this on my Harley for storage . Made clean up way easier & kept corrosion down . You can spray it on anything


good luck , your really gonna need it

you shouldn't put a steel or aluminum bike on a boat like that it will be destroyed in short order. I would find a bike like the Bridgestone mentioned or some other stainless steel, or titanium frame. If you have no choice than you need to coat the inside of the frame and fork with either JP Weigle's Frame Saver or BioShield T-9, or ACF-50. Then while the seat post is removed coat the inside and the post with a thin layer of waterproof grease, some will ooze out when you reinsert the post simply wipe it off, and do the same for the bottom bracket threads, water bottle bosses threads, etc. Get a head set external seal made by Lizard Skins and put it on after the waxing explained below. Then give the bike several good external wax treatments with either Mothers California Gold, or Mequiar's NXT, then use a spray wax from either of those two brands and just hose the entire bike without wiping it off (I would do the rims too BUT you'll need to wipe down the brake surface of the rim with a cloth dampened in a mild solvent before you ride or you'll go weeeeeeee as you crash!)

Getting a titanium bike may solve your rust problem, but then you have worry about those bolt cutters everytime you lock your bike outside. While security at the marina may be ok, once you ride it to work, and leaving a titanium bike locked outside is an invitation for bike thieves.

Either you get a aluminium beater, or get a folding bike that you can keep on board and when you ride to work, you can fold it and keep it under your desk.

Depends .. aluminums..

If the alloy is 7000 series it contains Zn.. (thats what the 7 indicates) 7005, 7075.

(C + Zn works for a battery)

If 6000, it doesn't, contain Zn. Ala 6061..

titanium is used as piping for really nasty fluids, way off the Ph 7 neutral .
Acids and harsh alkalies

Not if they aren't in contact. Any other metal (aluminum, steel) in contact with Ti will be sacrificial.

LOL!

All I can think of with cosmoline is boiling gun parts from old Russian Mosin Nagant rifles to get that crap to boil off. Yuck!!

Quite honestly, this might be the perfect use for a BSO. With minimal maintenance it could hold up for a year and then be allowed to disintegrate....