We were reviewing the weekly batch of photos from New Zealand today when we were interrupted by some cruisers wanting to chat. We traded sea stories for a while, discussed where they and we were headed, and generally got to know each other in the time honored cruising fashion.

They were astounded when we told them that we’d just turned the clock on 4000 hours of engine time. “But your boat smells so new” was their reply.

We hear the smell (or lack thereof) comment a lot.

We are so used to having a fresh smelling boat – we learned the secret years ago – that we have forgotten how nice it is.

Smell typically originates in engine room areas that are hard to clean, and in bilges that become coated with mold and mildew. Once it starts, it is very tough to eliminate.

We approach this in a series of ways. The first is to isolate the engine room from the rest of the boat (one of the reasons we like aft engine rooms). Next, make sure that engine room areas are accessible for cleaning. We avoid hiding plumbing and wiring behind modesty panels because they make inspection and maintenance difficult, and are hard to clean behind. We use closed crank case vent systems to reduce (or eliminate) blow by so the engine room stays cleaner.

Next are the bilges. Below the living areas we don’t have any. The entire hull bottom between the engine room bulkhead and the forepeak bulkhead is a series of tanks. There is no bilge to get wet and moldy.

Of course there is a lot of topside and deck area that could sweat in cold climates. To minimize this virtually all of the topsides, underside of deck, and tank tops under sleeping cabins, are insulated with Armaflex. That is the black material you see in the lead photo of this blog.

There are a few more tricks as well. Warm air holds more moisture than cool. So to minimize mold and mildew you want cool air outboard of the interior (inside of lockers, general storage areas, and between head and hull liners and the outer skin of the boat). Contrary to what many think, you do not want to warm these areas (something we have learned the hard way).

Insulating heater hose and domestic water pipes reduces heat leakage into these areas.

The basement on the FPBs creates a new set of design parameters. We want it cool in cold climates. So heater units bring their return air directly from the living space. On the other hand, in warm areas you want to dry the basement, which means it needs to be cooled. To accomplish this the salon and forward cabin air conditioners draw their return air through the basement (the basement has a large return air vent in the salon furniture).

Here are the key elements:

• Isolate engine room from living area.
• Have access to engine room surfaces for cleaning (and inspection).
• Insulate hull surfaces (helps with fiberglass boats too).
• Insulate heater and domestic water plumbing.
• Isolate areas between interior and hull to keep them as cool as possible.
• Minimize or eliminate bilges under living areas.

There you have the formula.

We have previously discussed minimizing condensation when living aboard, and when the boat is stored. But to briefly recap:

• If windows begin to fog in cold weather thirty seconds to a couple of minutes of air conditioning time will clear them.
• During and immediately after showering, we sometimes run the air conditioner to pull moisture out of the air (the air conditioners are run on the inverters).
• When the boat is in storage a small dehumidifier is run and the boat is left sealed.