Mothballing Moonshadow for the Winter

For the last few years, we have been “part-time” cruisers, leaving Moonshadow under care in a marina and returning home to New Zealand for the southern hemisphere summer. Our experience with this has been mostly positive as we’ve learned both first and second-hand how best to “mothball” the boat before we leave her for up to half a year. Over the years we’ve developed a checklist of things to do before we lock up and leave. For those of you planning to leave your boat for extended periods of time, we’ll share with you this information.

Sails: Removing all the sails prevents them from suffering from damage from wind and ultraviolet rays as well as discoloration from mold and dirt. When they come down, we take the opportunity to inspect and make any minor repairs before bending them on for the next cruising season. We like to store our working sails inside the boat where the dehumidifier can keep them dry.

Rigging: Stowing the spinnaker pole on deck reduces windage that can cause more heel and movement during a winter blow. We remove all the genoa cars and soak them in a strong solution of white vinegar and water. This dissolves much of the salt and mineral buildup that has accumulated during the season. Spraying coiled lines and exterior canvas with a biodegradable product like “Wet and Forget” will help prevent the growth of mold, mildew and gunge.

Dinghy: We give the dinghy a good cleaning and flush the outboard engine at the end of the season. It’s also important to drain any remaining fuel from the carburetor bowl so it doesn’t coagulate and block the ports and jets. We stow the dinghy on deck and cover it to protect it from UV damage.

Exterior: UV is the worst enemy to accessories, so we try to remove and stow as much as we can-cushions, BBQ, awnings, etc. are much safer down below. We have covers to put over sheet winches, the binnacle and cockpit compasses and all instrument displays. We install extra chafe protection on contact points of all dock lines and seal all shore power cord plug connections with PVC electrical tape. All valuables are stowed below and the forepeak, lazarettes and deck lockers are locked.

Below the Waterline: All sea cocks are closed. Make sure that any under water zinc anodes are at or near 100% of new. If the marina is “hot” with stray electrical current you’ll need all the protection you can get. Pulling the knot log impeller will keep it clean till it is needed again. It’s easy to do this without getting any water inside. I go under the boat and put my hand over the opening while Merima pulls it out and installs the dummy plug. Placing a black plastic bag (or two) over the prop and fastening them over the shaft with a couple wire ties will prevent or greatly reduce marine growth where there is no anti-fouling. Stuffing a rolled up plastic bag around the shaft at the stern tube will prevent crusty stuff from growing on the shaft inside the grooves in the cutlass bearing. Don’t forget to remove these covers before you try to motor out of the marina next season.

Engine Room: Most watermaker membranes must be “pickled” with a storage chemical during extended periods of non-use. I have installed a “closed loop” plumbing system to make this task relatively easy. Even if lube oil is relatively clean, once it has been used it may contain acids that, over time, may be harmful to the inner workings of an engine. At the end of the season I drain and replace all lubricants from the engine, transmission, genset and even the high pressure pump for the watermaker. The same applies to coolant on fresh water cooled engines and gensets, so I flush the cooling systems and put in new coolant at this time. While you’re in there, it is a good time to inspect and replace any zinc anodes on the engine, genset, transmission oil cooler and water heater. When this is all done, I flush the salt water side of the systems by pouring fresh water into the sea strainer with the sea cock closed and run the engine and genset for a minute or so.

Tankage: Condensation can form in the air space of diesel tanks when the temperature drops, leaving water the fuel supply. Add water to diesel and you have the perfect breeding ground for biological growth. We top up the tanks at the end of the season and add a biocide to help prevent this. We also put a few tablespoons of bleach in the water tanks as we fill them up to keep them sweet.

Electrical: Equalizing the battery bank will extend its useful life. See the Offshore Cruising Encyclopedia for more information on this. We try to do this regularly when we are plugged into shore power and certainly at the end of the season. After this is done, I top up the batteries with water, check and clean all the battery terminals and cable connections and brush some grease on them. We keep a smart charger on to top up the batteries to insure that the bilge pumps have power. The engine/genset start bank master switch is turned OFF to minimize voltage loss.

Below Decks: The biggest challenge is to prevent or minimize mold, mildew and odor in our living area. We have a small automatic dehumidifier that really helps keep things dry. It has a fitting on the back to which we attach a hose so that it can drain into the bilge, eliminating the need to empty the water tray. Goldenrods (small heated bars) in the aft staterooms and forward head help keep air circulating and the extremities of the living area dry. Wiping ALL interior surfaces with a 50/50 solution of white vinegar and water helps to prevent growth of mold. We prop or leave open all the drawers, lockers, the fridge and freezer box to allow air circulation. To prevent the salt water lines and heads from getting that “rotten egg” smell, we flush all the salt water lines with fresh water with a bit of bleach added, and pump it through the heads before shutting the sea cocks.

Caretaker: Having a responsible caretaker to look in on the boat on a regular basis adds greatly to our peace of mind while we are away. We provide them a detailed check list of what to do and ask that they check boat weekly, making sure that fenders and dock lines are secure, the shore power cord is plugged in, the battery charger and dehumidifier are on and that the inside of the boat is not full of water and the bilge alarms squealing. It’s also nice to have the hatches opened to air out the interior from time to time and the decks rinsed every now and then to remove built up dust and/or bird droppings. We provide them contact details should there be any questions or problems, but so far, we’ve had none.

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