That is interesting, To my knowledge the alternator on my 2001 225 Opti is 18 years old and never been replaced and it is down on a low pod just above sea level. It is possible to mis-align the two halves of the lower cowling or have a damaged seal. Rather than a major design problem however, I understand it is expected that sometimes water may get under the cowling. For that reason there are short drain tubes through the underside of the lower cowling halves. When water gets into the cowling they allow it to immediately drain out rather than get trapped in what is essentially a tray made by the two lower cowling halves and then splash around the motor under the cowlings like a washing machine including getting up high and into the electrics, alternator, starter etc. Those drains have check balls in them and it is somewhat common for those tubes and small check balls to get clogged up with bits of paint, dust, sand, dry salt, sea crap, grease etc. so that they don't move to let out water that gets in through other means. Lots of people don't know that those drain tubes and check valves have to be checked and cleaned regularly or general corrosion or water damage to electrical components is much more likely to occur. It would surprise me if there is a a major design fault with that motor. They went out of their way to design them to be salt corrosion resistant. PS before we put the cowling/s back on we always spay down the motor with a corrosion preventive - a tip from the local dealer mechanic.
