Recent months of wet weather have left many boat owners with a dilemma – they have been experiencing significantly more mould and mildew growth than usual in their boats. I have even noticed heavy mould growth on the inside of flybridge clears which I haven’t seen to this extent for years!
It’s a very real problem we have to contend with, and nobody enjoys the smell and unsightly look of mould on their cabin walls, cushions and even in the cupboards. Fewer enjoy the cleaning process. However there are measures that can be taken to help prevent mould developing in the first place.
In this column I will be offering a few practical tips that we use on our clients’ boats to keep mould at bay with great success.
Mould is one of many forms of fungus present everywhere in the world. It is a very primitive plant form which feeds on other plants and produces microscopic seed like spores that float freely around the cabin. These spores are always present, but it takes a particular set of conditions to encourage their growth. Unfortunately, the ideal conditions for mould are in a dark, damp location, just like your boat.
There are many products on the market that can help fight mould, but these should not be your first weapon against it.
The best way to fight mould onboard is to keep it from ever starting in the first place. Prevention is your best defence. When storing your boat or leaving it closed up for extended periods, a few simple steps will help prevent mould.
The first essential step is regular cleaning of the interior. This means wiping every surface down to remove any food or dirt particles that enable mould to get a foothold. Use a diluted water-bleach mixture on surfaces not likely to be damaged by the bleach. Wipe down and dry the head, shower, sinks, and the galley counters. Do the same for the overhead and walls and bulkheads. Secondly, since dampness is essential to mould growth, it stands to reason that you should not stow wet gear like spray jackets, cockpit cushions and even wet lines below. Clean and dry everything first!
Leave open all drawers, doors, and lockers to promote circulation. If covering the boat, create ventilation between the cover and the hull by hanging a few fenders between them and leave some ports or hatches open which are unaffected by rain or storms. Prop up mattresses and cushions, and anything paper such as charts, books, paper towels, etc should be stowed in air-tight bags. On a lot of my clients’ boats we leave as many deck hatches open as possible creating ventilation into areas such as the lazarette and the bilge area – just don’t fall down them next time you climb aboard!
Good air circulation and moisture control go a long way towards keeping mould at bay. Keeping the relative humidity below 55 percent throughout the boat gives you a good chance of preventing mould growth.
I have purchased dehumidifiers for many of my client’s boats and they have been very effective in keeping everything dry down below, especially yachts that get very wet inside after racing. We position them in the galley and place the overflow into the sink.
Moisture-absorption packets like silica gel can also help. These porous granules absorb up to half their weight in moisture from the atmosphere and can be purchased inexpensively at hardware stores. Place them in lockers and nooks out of the way, and check and replace them regularly.
Fresh air discourages the growth of mould, so it is a good idea to provide as much ventilation to your boat’s interior as possible. On a lovely clear day drop down to the club and open up the boat for an hour or so to get a good flush of fresh air through her.
If your flybridge is enclosed with clears, have your trimmer add a mesh section into the doorway to enable ventilation. An enclosed flybridge is a real hothouse!
If mould has already got a foothold there are numerous household products available. Some marine chandleries also carry a range of anti-mould cleaning products. However, it is a difficult and time consuming job and the noxious fumes can be overwhelming! When we are doing a particularly mouldy internal clean job, we often have to spread it over two days to avoid an overdose of bleach fumes!
There are far too many tips on mould removal to go into detail here. The best tip I can give is prevention! The three golden rules are – keep your boat very clean, always dry her properly before leaving and review how you can change things to provide good ventilation when left on her moorings.
Tips for mould prevention
- Regular thorough cleaning of all surfaces on the interior of your boat
- Make time to clean and dry everything before locking up the boat after a trip. If everyone is in a hurry to leave as is often the case, make a point of coming back the next day or have a professional do it for you.
- Provide better air circulation. Open all cupboards, hatches to the bilge and lazarette, drawers, cupboards etc and lift cushions onto their edges.
- Consider installing a dehumidifier or moisture-absorption packets
- Never stow sails, lines, wet weather gear etc when they are damp or salty as salt attracts moisture. Fresh-water rinse all this gear and leave out if necessary to dry properly before stowing.
Peter Jenyns is a long time member of RQ and well known within the boating community having spent a lifetime on and around boats. He is an accomplished yachtsman and fisherman and has worked as a Master Class V Captain. He now operates Professional Boat Care which specialises in boat detailing and maintenance programs. If you have any questions feel free to call him on 0409 930 888