If the cabin smells musty when you recommission the boat for the season, start with a dry-out and a source check. Air her out, pull the soft goods, check the bilge and the head, and recharge the locker bags. Once shore power or a generator is on and the AC fan can run, AIRLOCK One is the whole-boat answer for the stale smell in the cabin air. It installs by the AC air handler, one per AC unit, and eliminates odors in the air the AC moves through the boat whenever the fan runs. Most boaters install it in 15 to 30 minutes. For a head, galley or berth that still smells, add AIRLOCK Voyage in that spot alongside One. For why a stored boat goes musty and how to close her up in the fall, see why boats smell after storage.
What that spring-commissioning smell usually is
Most of the time it's trapped damp and closed-up air. A boat that sat sealed for months under a cover or shrink wrap holds every bit of moisture that was aboard when you closed her up, plus condensation from cold nights. Cushions, bedding, carpet, lockers and the headliner soak it up, and the air has nowhere to go.
Jeff L., a boat owner, came back after "a couple months of being closed up for winter" and wrote that "the dreaded musty smell hit me the second I opened the cabin door."
Usually it's that, and not a new problem. Still, check the usual sources before you blame the air, because standing water in the bilge, a head hose or a freshwater tank can all add their own smell after a winter.
Day-one checklist
- Open her up. On a dry day, open the hatches, ports and companionway and let the boat air out for a few hours.
- Pull the soft goods. Take cushions, bedding, towels and curtains out into the sun and air, or home to wash. Stand cushions on edge so both faces dry. See our guide to musty boat cushions for foam that won't dry out.
- Wipe and look. Wipe condensation off hatches, ports and the hull behind lockers. Note any wet spots, because they point to a leak to fix before the season.
- Bilge. Pump it dry, clean it and dry it. Standing water in the bilge is where the rotten-egg smell starts.
- Head and holding tank. If the head smells, do the hot rag test on the hoses and check the vent and seals. Our head and holding tank guide has the full checklist.
- Fresh water. Water left in the tank and lines can smell bad after a winter. Flush and sanitize the system following the manufacturer's instructions.
- Locker bags. Check the AIRLOCK MoistureGuard and OdorGuard bags you left aboard (see below).
- Batteries and fuel. A fuel smell or a rotten-egg smell near the battery bank is a safety issue, not an odor job. Turn off the charger, ventilate, and have it checked before you start anything.
The locker bags you left aboard
If you put MoistureGuard and OdorGuard in the lockers in the fall, spring is when you recharge them.
- AIRLOCK MoistureGuard is a silica desiccant for lockers, closets, drawers and compartments. If the indicator has turned pink, microwave the bag on high for 5 minutes (based on a 1000W microwave), let it cool for 5 minutes and put it back. Blue means ready. Each bag is reusable for up to a year, so a bag from last spring may be due for replacement.
- AIRLOCK OdorGuard coconut shell charcoal bags trap musty odors in the locker they sit in. Recharge them in the sun about once a month and replace them every 4 to 6 months. A bag that sat aboard all winter is likely due.
Both bags work only inside the space they sit in. They don't clear the cabin air.
Power back on: let AIRLOCK One do its part
AIRLOCK One works only when it has power and the AC fan runs. It did nothing while the boat sat unplugged all winter, and spring is when it goes to work. Once shore power or a generator is on:
- Run the AC fan. Cooling isn't required. One eliminates odors in the air the AC moves whenever the fan runs.
- Give it days, not one afternoon. A boat that sat closed for months usually needs a few days of fan time at launch for the storage smell to clear.
- Install now if it isn't fitted yet. Commissioning is a good time, since you're opening up the boat anyway. Most boaters install AIRLOCK One in 15 to 30 minutes with a magnet plate or screws and two wires at the air handler, and a marine tech can do it if the air handler is hard to reach. You'll need one per AC unit. See how to install AIRLOCK One.
Zones that still smell: AIRLOCK Voyage
Some spots hold the smell longer, usually the head, the galley or a forward berth. Put AIRLOCK Voyage there, alongside AIRLOCK One. It plugs into a 12V socket or a wall outlet and has an odor removal range up to 4 ft.
| AIRLOCK One | AIRLOCK Voyage | |
|---|---|---|
| Covers | AIRLOCK One: the whole boat through the AC; one per AC unit | One zone, up to 4 ft, alongside AIRLOCK One |
| Needs | Shore power or a generator, and the AC fan running | A 12V socket or a wall outlet (both plugs included) |
| Install | 15 to 30 minutes for most boaters | Plug in and place |
| Upkeep | Nothing to replace | Nothing to replace |
| Ozone | Not an ozone generator; certified to UL 867 | Not an ozone generator; conforms to UL 867 and CARB certified |
Humidity is a separate job
If the cabin stays damp after the first week, with ports fogging every morning and lockers smelling musty again, that's a humidity problem. A hygrometer tells you. The EPA says to keep indoor humidity below 60%. A dehumidifier or the AC brings humidity down. AIRLOCK One is not a dehumidifier and doesn't lower humidity. See our boat cabin humidity guide and boat dehumidifier guide.
Plan next fall's close-up now
The easiest spring is the one you set up in the fall. Take soft goods home, pump the bilge dry, put fresh MoistureGuard and OdorGuard bags in the lockers, and work out venting with your cover. The full steps are on why boats smell after storage. For the year-round causes of boat smell, see why boats smell.
Spring commissioning boat smell FAQ
Why does my boat smell musty when I open her up for the season?
A boat that sat closed for months holds damp and stale air in the cushions, lockers, carpet and headliner, and condensation adds more moisture. Standing water in the bilge, a head hose or the freshwater system can add their own smell. Dry out and check those sources first, then treat the cabin air. For the storage-side causes and close-up steps, see why boats smell after storage.
What should I do first on spring commissioning day?
Air the boat out, take soft goods into the sun or home to wash, wipe condensation, pump and clean the bilge, check the head and fresh water, and recharge the locker bags. Treat any fuel or battery smell as a safety check before you start anything.
Will running the AC alone clear the smell?
Running the AC fan moves the air, but it doesn't eliminate odor on its own. With AIRLOCK One installed at the air handler, the AC airflow carries the treatment through the whole boat whenever the fan runs. Dry out the soft goods and fix the sources too.
When should I install AIRLOCK One, fall or spring?
Either works, but it only does something while the boat has power and the AC fan runs. Many owners install it at spring commissioning, since they're opening up the boat anyway. Most boaters install it in 15 to 30 minutes.
Do MoistureGuard bags left aboard over winter still help?
Yes, inside the lockers they sit in, but they may be full by spring. If the indicator is pink, recharge the bag in the microwave. Each bag is reusable for up to a year, so replace older bags.
Should I use an ozone generator to shock the boat at launch?
We don't recommend ozone generators aboard, and a one-time blast doesn't fix damp soft goods or a smelly bilge. AIRLOCK One is not an ozone generator and is certified to UL 867. AIRLOCK Voyage is not an ozone generator either, and it conforms to UL 867 and is CARB certified.