by Robert Maitland
The following information has been gained from 35 years on my experience of preparing a boat for winter and information from others who were not so fortunate.
So why bother to winterise? Over half of boat owners don’t do any winter preparation other than pull a cover over their boat to reduce the water leaks.
If your boats calorifier (engine domestic water heater) has a body leak or repaired crack or leaking engine block expansion plug, then a previous owner of your boat most likely was one of the 50% that didn’t bother.
Another group think that keeping you boat in the river flow will stop jack frost from doing his worst. It might just work for all below floor equipment in out milder winters.
Many of you know that electric tube heaters under your engines did not stop frost damage during the winter of 2009/2010 (coldest since 1987) where many boats suffered frost damage to oil coolers, seacocks and other engine and boat parts. My insurance company wrote to me June 2010 requesting everyone not to rely on electric heater to winterise their boats but to follow the manufactures advice on the subject.
I will split the subject into the following areas: –
- Mould Growth
- Engine internal water-cooling circuit.
- Engine once through water cooling system. (river/sea water cooling system)
- Domestic water systems.
- Seacocks.
- Summer canopy.
- Outdrive systems.
- Outboards
- Fuel tanks
- Batteries
1. Mould Growth
Mould growth is a constant battle on a boat. Some people use electric heaters which is not environmentally friendly as it wastes a lot of electricity. Others use dehumidifiers.
On our boat every internal surface including all glass, window frames, side, and roof panels, that’s everything except soft furnishing is cleaned down at end of season.
Our Broom boat manual states that all drawers be left open and if you put a cover over the boats, leave all windows on vent. We prop open the anchor chain locker (front cabin) to aid ventilation.
Many people put their faith in dehumidifiers. These are not very environmentally friendly as most boats have fixed ventilators. Mine has eleven. For them to work on my boat I would have to seal all 11 vents with duct tape. If you do nothing the dry air they produce will escape from your boat several times a day. Same thing will happen if you use an electric heater in the cabins.
Our policy is to put a fan on timer in the front cabin (poor ventilation here) and 1/2 kg bag of silica gel in each wardrobe/cupboard with doors closed. Silica gel turn from white to blue as is absorbed moisture. It can be re activated with heat from the top of a radiator or microwave for use the following season. Note that the paper bags that the silica gel comes in will not last more than one season. We re bag the silica gel in ski goggle cloth covers which are available online and come with draw strings which should be tied tight.
2. Engine internal water-cooling circuit.
This is a simple one. Replace all the coolant every 5 years with 1 part antifreeze to 2 parts water. Be wary if previous owner says the engine was fully serviced. That can mean different thing to different people. Best to see itemised list of work done during service.
Don’t forget the generator needs the same attention.
3. Engine river water cooling system.
I used to do this job on my own but it much easier and with less potential future trouble if you have someone to start and stop the engine (no disconnection of hoses). The job can be done in the water or on the hard.
First action is to prepare the mix of 9 litre consisting of 1 part a antifreeze to 2 parts water in a 10 litre container. (that size is easy to pour). That’s enough for a small engine of 80HP but my 300HP engine needs double that.
Then gain access to the engine water weed filter, shut the seacock, and remove the filter element. On the tall filters I use a big heavy-duty funnel and pour in the mix as your helper starts the engine and stops it when you have poured it all in. I always get my helper to practice stopping the engine before we do the real thing as they will have to act fast when you yell “stop”. You will spill some the first time you do it. On the plastic water weed filters, the wide type, the funnel is not required. Just pour it in.
If you are winterising in the water and have an older 1/4 turn ball seacock without the little body drain valve, then fill the filter to the top with the mix and open and close the seacock. This means that the trapped water in the seacock body is replaced with an antifreeze mix. If your boat that the little drain plugs on the side of the sea cocks, remove this plug and drain out any water. Opinion is divided on whether to replace the plug or leave it to the spring. If you forget to replace it, your boat might sink when you open the sea cocks.
When I winterise a boat for the first time, I collect the exhaust water in a 25litre container and measure the SG (specific gravity) A figure greater than -10oC is a good result and confirms the volume of mix needed to do the job.
4. Domestic Water System
Empty the holding tanks first. Pump out your domestic water through only one tap. When its starts blowing air, shut it and open another. Repeat for all hot and cold taps including electric toilets and shower mixers. Remove the shower head and leave the hose on the floor without a loop to drain.
To safeguard a calorifier from frost you need to remove at least 80% of its water contents.
Most calorifier have 5 connections. 2 from the engine, 1 cold water with a brass/silver colour NRV (non return valve), 1 hot water outlet and a temperature pressure relief valve. You may be lucky to have a drain valve fitted but if not disconnect the cold-water inlet between the NRV and the calorifier. Take care not to lose the O ring. If the water drains very slowly disconnect the hot water outlet. It best to mark the two engine pipe connections with yellow or white tape, the hot water pipe with red tape and the cold with blue tape before you start to avoid a mix up.
Some boat Calorifier’s are mounted vertical with no accessible drain valve. On a Rosebank boat the owner used a 500ml Sealey oil suction syringe as using a syphon to remove the contents was not possible. Sometimes you must look at the problem and come up with a solution. A drill operated pump would also have worked.
Next disconnect the domestic water pump discharge pipe and run the pump for a few seconds. If a drinking water filter is fitted its best to remove the element and take it home and back flush it with a water hose. I get 2 years out of these filters. I keep mine full of water in my garage with each end covered to prevent dirt ingress. When all water has stopped running reconnect all pipework. Some people recommend blowing out all pipework with compressed air before re-assemble.
Operate all bilge pumps until the bilge is clear. If you are fussy, dry our you bilge with a mop and bucket.
For Toilets and Shower/s make up a mix of 1 part antifreeze and 4 parts water and pump 4 litres through each toilet discharge with the water inlet seacock shut. One litre should be enough for the shower pump. If a shower drain pump is located in a small sump container, this is a good time to clean it out (messy job) or use two litres of mix.
5. Seacocks
Insurance companies require that all seacocks are shut when a boat is unattended. They mean every time you leave the boat. During the severe frost of Jan 2010 some seacocks fracture leading to water ingress. The Americans have the solution as some parts of USA have very severe winters. Their seacocks have a body drain plug to let out trapped water.
Here if the boats is in the water all seacocks shut. If out of water all seacocks open.
Do tie a label to the steering wheels stating how many seacocks are shut with the date on it.
6. Summer Canopy
If you have one, wash it inside and out (don’t use a power washer) dry it and store in a dry place for the winter.
7. Outdrives.
These engine drives are much more difficult to winterise. On some installations there is/are oil cooler/s in the suction circuit between the drive leg and the weed filter. Therefore, this suction circuit can not be winterised by pouring the mix into the water weed filter.
For most people its best to get a professional to do the job as some recommend disconnecting the suction pipework and draining any water. Failure to replace this pipework properly will lead to engine overheating/failure first time out.
If you are keen and competent it can be done using outdrive/outboard water flushing ear muffs with boat out of water with the leg down. Do not open the raw water filter at this time as you will let air in and loose the prime.
There are kits available, or you can make up your own. A 20 litre container with a 2 metre length of 12mm flexible hose connected to the bottom of it with the other end connected to the flushing muffs. Rig the 20 litre container as high as possible. Fit the muffs and add 15 litres (small engine requirement) of the usual anti freeze mix to the 20 litre container. For larger engines use 15 litres of mix twice. Weed filter cap/cover must be securely closed. Best to get a helper to start and stop the engine while you check if it’s sucking the antifreeze mix from the tank. When the container is empty, Job done.
8. Outboards
With the new E10 Petrol (10% renewable ethanol) methods of winterising outboards have changed. The old way was disconnecting the fuel line and run the engine (using water cooling earmuffs) until it stopped. Then check all engine fuel lines were clear and drain the carburettor. Some people used fogging oil spray down the plug hole. Fuel injection has added another dimension.
As my 2 mercury outboards are under warranty my local dealer is servicing and winterising them at the same time. He tells we that the recommended method is to add the appropriate amount of fuel stabiliser to the fuel tank (quite a lot for my 160litres), mix it up and run the engine until the petrol mix its through to the engine. No draining of petrol required. Store outboard in the vertical position if fitted to boat. Best to consult your local outboard expert/dealer before attempting this job.
9. Fuel Tanks
For petrol tanks see section 8.
Best to do this check with boat in the water just in case you have to add fuel treatment. Its easier to mix it in the water than out.
Diesel tanks. I am not a 100% certain but I think UK and Ireland biofuel is B7. That’s up to 7% biofuel to 93% diesel. Have heard various opinion about adding fuel stabiliser and/or filling tanks full for winter. I think the jury is still out on the subject, so I just top up my tanks for winter.
Biofuel and water will create havoc in your fuel tank. If at all possible, have your tank checked for water. If your fuel tanks have a sump and drain valve, remove the sealing plug, and drain some fuel into a clear glass. Hold it up to the light and check for water. If any water present drain 5 litres and check again. When you have drained any water out add the correct amount of diesel bug killer and insure a good mix.
10. Batteries
AGM and sealed lead acid batteries only require to be kept fully charged during the Winter. Many Brooms are fitted with 6V Semi Traction open cell Lead Acid Batteries. These can use a lot of distilled water. Each of mine use 1 litre each per year of distilled water. Beginning of winter is a good time to check the acid level and several times during the year. Turn of the main battery isolators and ensure the batteries remain fully charged during the winter. A half-charged battery is a battery slowly dying.
Some people are happy to fit new batteries every 18 months. My domestic batteries are still in good shape after 18 years. The secret is to keep the acid level above the plates and leave the charger on when you leave the boat.
General advice.
- Winterising your boat in the water carries more risk than on the hard. However, boats moored in the flow of a river are at much less risk of seacock damage/fracture than boats winterised in an enclosed mooring or harbour with no flow under the boat. One of my friends solved this problem with an electric trace heating cable but again how secure is your electric supply. I don’t have all the answers.
- You may have noticed that I recommend reconnecting every pipe and fitting in the above process. It takes more time but come the spring you just fill the water tank, open all the sea cocks and you are good to go.
Have fun
Robert Maitland
