MG Spring 25 - Condensation

[sutton sailor]

I bought a MG Spring 25 last September. After I had bought her I found inside some of those condensation traps, so I thought this may be a problem. On the 36 hour trip from Plymouth to Southampton there was no problem. But there was plenty of wind and water outside !!
Over the winter in the boat yard I have had a lot of condensation. What I did initially was to replace the absorbtion tablets in the condensation traps. The boat had no ventilators as such, so I left the fore hatch locked in the 1/2" open position, the main hatch slides over the washboards and leaves a 2" wide by 18" long horizontal gap. I left the cabin and heads open. When I first returned 6 weeks later there was condensation everywhere and black mould was starting to appear. I fitted a solar powered ventilator in the rear cabin deck head. The camber of the deck was such that it's integral solar panel was canted toward the sun, and thus operates it's fan. This made an improvement. I subsequently fitted a 2nd solar powered ventilator in the deck head of the heads compartment. Unfortunately the camber of the deck is such that with the low altitude of the winter sun the light intensity was not sufficient to power the fan. Then to top it off the neighbours boat due south of mine which was a much taller boat to start with put up a cover so high the owner could walk over the deck unobstructed so it cuts out direct sun light to both solar vents. Apart from the condensation inside the boat I also noticed condensation in the huge cockpit locker, this space extends from the starboard side right arround the stern which is a sugar scoop style. Condensation form this locker seems to be leaking in to the bilge from the bettom of the starboard side and also from the stern through the internal moulding wetting the foam mattress. I am planning to do some GRP work to seal the leak into the rear cabin to stop the foam mattress getting wet. I could perhaps insulate the stern with closed cell foam, but this would be an unpleasant job as access is limited and there are a multitude of curved surfaces further complicated by the twin rudders and there associated linkage.

Can the forum advise. Please.

 

[peteK]

It sounds as if you are getting rainwater leaking in to get it that bad.

 

[pvb]

If you have black mould appearing, it would be worth cleaning every interior surface thoroughly with an anti-mould product. Polycell Mould Killer in a spray bottle would be suitable, it contains benzalkonium chloride, which should kill the mould spores. Other mould killers may only contain bleach (look for "hypochlorite" on the label) and won't be as effective.

Ventilation will usually successfully combat condensation. It sounds as if you have decent ventilation, so is rain water leaking in to the boat perhaps?

 

[sutton sailor]

Thanks for the sugestion ref:- Polycell mould killer, I just used dilute bleach which I could easily obtain. The possibility of a rain water leak had occured to me but I could not see any signs of water running down any surfaces. Apart from where it was running out under the internal moulding in the stern cabin. This was from a location wher the builders had cut away the moulding that formed the berth . The reason being that the built up GRP reinforcing the rudder post intruded into the berth moulding. The builders had cut away the berth moulding so it would lie down without distortion. This area was then sealed with a large volume of silicone rubber which is no longer intact. It is this area that I intend to seal with GRP. When I remove the internal moulding every square inch of the surface was covered with droplets of condensation.

 

[duncan99210]

Check the bilges for standing water: it may be entering through minor leaks round, say, stanchion bases or other deck fittings. Water will then track down the hull into the bilge, often without leaving visible marks. Once you’ve got a bit of standing water in the bilge, any measures you put in place to reduce condensation will face an uphill struggle.
I’d recommend ensuring that rain water isn’t getting in and sitting in the bilge, increasing the ventilation if you sensibly can and using a long acting anti mildew agents as suggested above.

 

[doug748]

It's been a very wet winter which means even tiny leaks get a big chance to do their worst.

I have:

A fitted cockpit cover so that I can leave the lockers 6in open, which sets a draught through the boat. I think you may have an opening cabin port.
The cover keeps the cockpit area dry which also helps.

Removed the engine and heads seacocks to let some air in at low level.

A box cover over the forehatch so it can be left 2in open.

Put condensation traps into critical areas like the engine bay, empty water tank, fore locker etc.


This normally does the trick but this winter I have noticed some spots of black for the first time in years. A heater or even a conventional bulb on a timer would help a lot, if you have power.

 

[sutton sailor]

When I first dried out the bilges I did so both under the engine and the stuffing box area and also under the cabin sole. When I next returned I found water had colected again under the engine , stuffing box area and in the cockpit locker but not under the cabin sole. At no time have I found water in the bottom of the lockers. I have heard that dusting all areas with talcum powder will help by showing the source of the leak. Has anyone any experience of this method. There is one other area that I am suspicious of. When I lift up the cockpit locker lid, it is a large structure that reaches from the coaming right down almost to the cockpit sole. It is hinged on the coaming and when raised rests on the gaurd rail. I found jammed in it's upper lip a row of 4 sponges which I initially thougt were there as some sort of seal. When I noticed this water problem I examined them and found them to be the sort of sponge that soaks up water ( Car wash sponges). I thought these might help water get in so on the last visit I removed them. I am thinking of replaceing them with sealed cell foam.

Suggestions Please.

 

[oldbloke]

I had a Spring for a number of years, and had similar problems.
I think there are a number of issues. The flatness of the hull and the floor stringers make it difficult (impossible) to get all the water out. At the very least lift all the floor boards and sponge the boat dry. If she is tilted backwards at all the water may collect under the engine.
Because of the internal moulding it can be difficult (impossible) to track a leak. I found rain could get in around the washboards, also cracking and leaks around the shroud attatchments are well known.
I too had leaking into the aft cabin. Improving the sealing helps , but getting rid of thw water, and lifting the mattress when leaving the boat seemed the best solution.