The state of the old Dahons that invariably get chucked by the boat owners at our local marina has made it clear that the ideal boat bike must be as simple as possible.
Ideally, you'll want some combination - or all - of this:
- No derailer - eventually you'll get a stiff link that'll ruin your day,
- Coasterbrakes preferred. Maintains the no-derailer mandate. Don't rely on an IGH's internal lubrication to keep it working either.
- The fewer the cables, the better - another reason for a coasterbrake. Avoids the issue of sticking calipers or rotted cables entirely. Remember, even if your inner cables are stainless, the outer sheath - specifically steel wire embedded between the vinyl outer cover and Teflon inner liner - usually isn't. This is particularly a problem with linear lined shifter cables. Some brands tend to crack their inner housing and turn into something resembling a miniature boiler explosion.
- Stainless spokes, aluminum rims.
- An absolute minimum of chromed steel parts, if any. Expect them to become solid rust balls.
- Kevlar-bead tires. Avoids the possibility of premature tire failure at the bead due to wire beads rusting from the inside out.
- Sealed bearings on the hubs a plus, rubber dust caps on conventional cones a minimum. May not be possible for the rear as high-end coaster brakes won't be spec'ed by most manufacturers. Not worth the non-standardization either; most cheap coasters of the last 15 years are identical and take all of 10 minutes to swap. Sometimes you'll find them on kid's bikes, meaning a run to the local thrift store could net you a replacement hub.
- I've never tried this, but I wonder if corrosion at the valve stem could be staved off with some plumbers' grease....never tried, don't know. Never seen a valve get bad enough from corrosion to prevent sealing, so possibly over-the-top.
- Don't even consider the Brompton. Get the cheapest thing you can, because it will become ratty. The salt environment is no place for a boutique $1,000-plus folder, even if it is one of the best folding designs ever. It might not be a bad place for a cheap knockoff of one though, but I'd inspect the chain tensioner design thoroughly for zinc plated parts that'll have the lifespan of a duck in a trash compactor.
-Kurt