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Condensation


dm6045

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Hello all the last couple of nights we have noticed a lot of condensation on the porthole in our office at the stern. we have never particularly suffered from bad condensation before but it was so bad that it fully soacked two microfibre cloths that we put on the porthole liner between dinner and bedtime, im just wondering if it was caused by the weather getting colder or if it could be something else?

i dont think it could be poor ventilation  as trevor whiting who did our survey and bss last year said we were overly jenerously ventilated as in the office alone there are the rear doors to stern (very draughty) side hatch (again draughty) two mushrooms and a pidgeon box. And judging by the average temperature of the room i would confirm its very well ventilated. There was also quite alot of condensation in the bedroom that also has good ventilation (another 2 mushrooms and a pidgeon box). We had the stove going full out which i always understood helped with condensation and all the internal doors always open so good airflow. I have checked the drain holes on the windows and they are clear but theres so much water its running down the woodwork. I put new moisture absorber things everywhere. Is there anything else i could do or that i should be checking to help find the cause?

Thanks in advance

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Condensation. Horrible stuff. Warm damp air on cold surface, walked in the pub on Sunday, couldn't see a thing, glasses misted up. I put double glazed units in the wheelhouse as warm air rises and single glazed units can stream with condensate, I also have double glazed units in the roof lights (dog box / pigeon boxes) All are successful. Therefore I would try to get a couple of discs of Perspex / polycarbonate to shove in the portholes and fix them in with ? draught excluder? gaffer tape? Others swear by cling film but condensation is a real pain.

 

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Warm / Hot air holds much more moisture than cold air.

Boiling a kettle and cooking all cause water vapour which is 'held' by the hot air.

Hot air hitting a cold surface will lose some of its water vapour as condensation onto the cold surface., the more cold surfaces (metal door frames, mushrooms, glass, window frames etc) the more condensation you will get.

Ventilation will do little as what it is effectively doing is cooling the air, so it can hold less moisture. What ventilation does do is allow the warm air you have just heated to escape taking some water vapour with it, and be replaced by cold air so you can heat it up again.

If you reduce the temperature of the inside of the boat you will reduce condensation - try measuring the relative humidity of the air in the boat - all that moisture is coming from your breath, cooking, washing/showering, washing pots, boiling the kettle, perspiring and generally 'living'.

It is interesting to note that 'water' secreted by an average adult male has been measured to be 400 ml due to respiration and 400 ml due to perspiration per 24 hour period of time.

That is the best part of 1 litre per person per day, add in all the other sources and it is easy to see why it is possible to get several litres of condensation per day in the 'wrong' conditions.

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Our Dog Box / Pigeon Loft underside was just painted metal and ran with condensation in certain conditions - this dripped onto the bed and made the bedding somewhat more than 'moist'. problem was solved by putting a couple of 1/2" x 12" pieces of wood glued onto the dog box sides at the roof-line height. A square of twin-wall polycarbonate sheet (as used on conservatory roofs) was cut to fit the hole and carefully jiggled in to sit onto the two 'rails'.

We had made a cover for the 'outside' which just went down on 'poppas', no bare metal left - but light could get thru the clear 'bulls eyes'.

Never a drop of condensation dripped again.

I have found that the best way to stop condensation is to have nothing cold enough to allow the air to condense onto.

 

IMG_20140428_115154.jpg

 

For the Port-Holes we had sliding 'shutters' fitted - no hot air got to the cold glass - no condensation.

 

 

 

IMG_1534.JPG

Edited by Alan de Enfield
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1 hour ago, dm6045 said:

Hello all the last couple of nights we have noticed a lot of condensation on the porthole in our office at the stern. we have never particularly suffered from bad condensation before but it was so bad that it fully soacked two microfibre cloths that we put on the porthole liner between dinner and bedtime, im just wondering if it was caused by the weather getting colder or if it could be something else?

i dont think it could be poor ventilation  as trevor whiting who did our survey and bss last year said we were overly jenerously ventilated as in the office alone there are the rear doors to stern (very draughty) side hatch (again draughty) two mushrooms and a pidgeon box. And judging by the average temperature of the room i would confirm its very well ventilated. There was also quite alot of condensation in the bedroom that also has good ventilation (another 2 mushrooms and a pidgeon box). We had the stove going full out which i always understood helped with condensation and all the internal doors always open so good airflow. I have checked the drain holes on the windows and they are clear but theres so much water its running down the woodwork. I put new moisture absorber things everywhere. Is there anything else i could do or that i should be checking to help find the cause?

Thanks in advance

As others have said realy. Colder outside warm inside more condensation. On this boat we have double glazing so no condensation ever on the glass however we get loads on the frames :rolleyes: Different boats have all had differing amounts of condensation over the years but basicaly if its metal and cold it will turn into a purpose built condensation maker.

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Thanks for the replies may have to look into some form of secondary glazing.

our pidgeon boxes dont suffer from condensation because they're lined and we have covers over them its mainly just the portholes. I was just worried about possible other causes as i know that cooking etc causes it so we always have the galley window open permanently and theres never a drop of condensation anywhere before the bedroom. But then  then bedroom is a good 10 degrees colder than anything forward of it and the office is even colder

we do need to cut an inspection hatch in the floor aswell because i think there is probably some water in the bilge as when we brought it the windows were leaking badly up untill now that its just been painted and windows re sealed. If there is water there would thst be making the situation worse?

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20 minutes ago, Alan de Enfield said:

Our Dog Box / Pigeon Loft underside was just painted metal and ran with condensation in certain conditions - this dripped onto the bed and made the bedding somewhat more than 'moist'. problem was solved by putting a couple of 1/2" x 12" pieces of wood glued onto the dog box sides at the roof-line height. A square of twin-wall polycarbonate sheet (as used on conservatory roofs) was cut to fit the hole and carefully jiggled in to sit onto the two 'rails'.

We had made a cover for the 'outside' which just went down on 'poppas', no bare metal left - but light could get thru the clear 'bulls eyes'.

Never a drop of condensation dripped again.

I have found that the best way to stop condensation is to have nothing cold enough to allow the air to condense onto.

 

IMG_20140428_115154.jpg

 

For the Port-Holes we had sliding 'shutters' fitted - no hot air got to the cold glass - no condensation.

 

 

 

IMG_1534.JPG

 Is this a reeves hull fitted by weltonfield? The roof fittings look remarkably similar to ours exept our vents are brass mushrooms and the woodwork looks very similar too?

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1 minute ago, dm6045 said:

But then  then bedroom is a good 10 degrees colder than anything forward of it and the office is even colder

There is the answer -

The air at the front of the boat is hot and holds more water vapour, your ventilation is 'sucking / blowing' the warm air to the back of the boat and as the warm air hits the cold air and cold fittings it starts to 'rain'.

Reduce the ventilation, insulate all the metal & glass, or get the back of the boat warmer - some might suggest an Eco- fan (but perish the thought).

Think of a nice Summer day :

The sun heats up the fields making thermals, the heat rises and as the height increase the temperature drops by about 3 degrees c per 1000 feet, once the warm air reaches the dew-point the water vapour is given up and becomes those nice cumulus clouds.

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2 hours ago, dm6045 said:

Hello all the last couple of nights we have noticed a lot of condensation on the porthole in our office at the stern. we have never particularly suffered from bad condensation before but it was so bad that it fully soacked two microfibre cloths that we put on the porthole liner between dinner and bedtime, im just wondering if it was caused by the weather getting colder or if it could be something else?

i dont think it could be poor ventilation  as trevor whiting who did our survey and bss last year said we were overly jenerously ventilated as in the office alone there are the rear doors to stern (very draughty) side hatch (again draughty) two mushrooms and a pidgeon box. And judging by the average temperature of the room i would confirm its very well ventilated. There was also quite alot of condensation in the bedroom that also has good ventilation (another 2 mushrooms and a pidgeon box). We had the stove going full out which i always understood helped with condensation and all the internal doors always open so good airflow. I have checked the drain holes on the windows and they are clear but theres so much water its running down the woodwork. I put new moisture absorber things everywhere. Is there anything else i could do or that i should be checking to help find the cause?

Thanks in advance

Sounds like you lust leave your portholes uncovered all night? If so they're bound to attract condensation on a cold night with the fire on inside the boat. 

I made porthole bungs made of ply and 1" thick medium density polyethylene foam - 14 of them.

After a very cold night they sometimes get stuck to the aluminium frames by a thin layer of condensation which has frozen! 

DSC00534.JPG

DSC00538.JPG

Edited by blackrose
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6 minutes ago, blackrose said:

Sounds like you lust leave your portholes uncovered all night? If so they're bound to attract condensation on a cold night with the fire on inside the boat. 

I made porthole bungs made of ply and 1" thick medium density polyethylene foam - 14 of them.

After a very cold night they sometimes get stuck to the aluminium frames by a thin layer of condensation which has frozen! 

DSC00534.JPG

 

We have similar and found we dont need a turn button at the top.

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11 minutes ago, ditchcrawler said:

We have similar and found we dont need a turn button at the top.

I found that I do need the turnbuckle! The bungs are 15" diameter and made of 12mm ply so they're fairly heavy and just fall out without the turnbuckle at the top. Also unlike some boats, my cabin sides have a decent amount of tumblehome so there's no way the bungs will stay in without some kind of restraint.

IMG_20180206_182544.jpg

Edited by blackrose
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1 hour ago, blackrose said:

Sounds like you lust leave your portholes uncovered all night? If so they're bound to attract condensation on a cold night with the fire on inside the boat. 

I made porthole bungs made of ply and 1" thick medium density polyethylene foam - 14 of them.

After a very cold night they sometimes get stuck to the aluminium frames by a thin layer of condensation which has frozen! 

DSC00534.JPG

DSC00538.JPG

These look quite excellent i may have to look into making some as we only have curtains at the moment

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We must be very fortunate or perhaps we don't breath very much as we have no condensation on kelpie. On each side there are 3 "proper" windows at the front and two portholes at the back. The fire and sitting area is at the front and the bedroom is at the back. We always have windows open, often all of them but if the wind is on that side of the boat, some may be closed. We have round cushion things to put in the portholes but we don't bother with them (they kept falling out anyway) and as the glass has leaf patterned clear fablon stuck to it privacy is not a problem. 

Haggis

 

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3 hours ago, Alan de Enfield said:

Our Dog Box / Pigeon Loft underside was just painted metal and ran with condensation in certain conditions - this dripped onto the bed and made the bedding somewhat more than 'moist'. problem was solved by putting a couple of 1/2" x 12" pieces of wood glued onto the dog box sides at the roof-line height. A square of twin-wall polycarbonate sheet (as used on conservatory roofs) was cut to fit the hole and carefully jiggled in to sit onto the two 'rails'.

We had made a cover for the 'outside' which just went down on 'poppas', no bare metal left - but light could get thru the clear 'bulls eyes'.

Never a drop of condensation dripped again.

I have found that the best way to stop condensation is to have nothing cold enough to allow the air to condense onto.

 

IMG_20140428_115154.jpg

 

For the Port-Holes we had sliding 'shutters' fitted - no hot air got to the cold glass - no condensation.

 

 

 

IMG_1534.JPG

I have sliding porthole covers as well best thing ever for both condensation and very tidy no curtains or blinds dangling around

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