Keeping cool

[Michael Puusta]

Hello, any thoughts on reducing heat build up in our increasingly hotter climate if no shade is available?  I'm new to boating and have nearly finished fitting out my forty foot narrow boat and noticed ( especially last year ) how hot it can get . Has anyone tried solar reflective paint on the roof , how effective is it and is it suitable for a narroboat roof ? I've fitted three mushroom vents with computer fans which do a great job stopping  condensation  and because once I get an idea I have to try it out have fitted two fans to draw cooler air from below the floor space and out through vents in  the wall panels  . Also I've put aluminium Venetian blinds on every window to reflect the sun  which when angled a certain way reflect the light from the water to give a pleasing rippling effect inside . Thanks in advance 👍

[Paul C]

A white roof.

[Lily Rose]

Seconded.

 

We never moor in the shade due to solar panels. Despite dark cabin sides the boat never gets unbearably hot (unlike the house) and I put this down to a combination of white roof and doors open front and rear to allow a pleasing draught.

[LadyG]

I used white grey rather than white which is less eye watering when steering, not gloss.  I'd not use anything  experimental as the roof takes a bit of hammering including from chimney.

I painted cabin sides white grey with black outlines.

I think my insulated curtains are effective and have windows cracked open to keep a through draught. Boat insulation too. 

Edited September 16, 2023 by LadyG

[robtheplod]

portholes rather than big windows help also.....

[Lily Rose]

25 minutes ago, robtheplod said:

portholes rather than big windows help also.....

 

Bit of a drastic solution though, unless still at the "looking for a boat" stage.

[blackrose]

I'm always surprised when people say they've painted their roof a particular colour and it sounds like they haven't used deck paint. I know others aren't necessarily single handed but I'm up and down on and off my roof a lot when I move and it's essential that surface has a good grip. You can add non slip aggregate to any paint colour of course but I see a lot of narrowboats with gloss paint on the roof and it just looks dangerous to me. You can't set foot on that stuff in the wet. The majority of accidents on boats are from slips and trips.

[nicknorman]

Presumably solar panels covering most of the roof and with an air gap between them and the roof will mostly keep direct sunlight off the roof and allow airflow and thus the roof will be at ambient temperature rather than egg-frying temperature.

[blackrose]

2 hours ago, Michael Puusta said:

Hello, any thoughts on reducing heat build up in our increasingly hotter climate if no shade is available?   👍

 

Why wouldn't there be any shade available? Our rivers and canals are lined with trees. Your boat does move doesn't it? When we had that 40C heat wave a year ago I took my boat out of the marina to find some shade. My neighbours stayed put and suffered. Unless you've got shore power & air conditioning finding shade is your best solution.

6 minutes ago, nicknorman said:

Presumably solar panels covering most of the roof and with an air gap between them and the roof will mostly keep direct sunlight off the roof and allow airflow and thus the roof will be at ambient temperature rather than egg-frying temperature.

 

Nobody so far seems to think the cabin sides transmit any heat into the boat?

 

Face it, you're in a metal box, it's going to get hot!

[DShK]

I've been looking at motorhome AC. Realistically it'd need a generator going or shore power. Another potential concern is the high in-rush current that could overload your inverter. A "soft start" device may be the solution.

 

What I did during that 40C heat was cover the boat in wet white sheets/towels and keep them wet. The water evaporating keeps the boat cool 

 

 

[Higgs]

It hasn't been that unbearable this year. But for two reasons, I don't moor in the shade - the solar panels and trees. The skinny trees aren't such a problem, it's those with heavy overhanging boughs I don't trust.

 

 

Edited September 16, 2023 by Higgs

[IanD]

57 minutes ago, nicknorman said:

Presumably solar panels covering most of the roof and with an air gap between them and the roof will mostly keep direct sunlight off the roof and allow airflow and thus the roof will be at ambient temperature rather than egg-frying temperature.

 

That's not really how it works; the panels get really hot in the sunlight, if flat-mounted hot air builds up underneath them (unless there's a crosswind, or fans...), and they also radiate heat down onto the roof. If they're tilted then this happens much less, the panels still got hot but the roof doesn't because it's shaded.

 

The roof will certainly be cooler than without the panels, but with flat panels certainly not as cool as ambient (air) temperature. The panels will be pretty damn hot in the sun though, up to 65C on a still day in midsummer, which also reduces output by 15%-20% depending on the panel.

 

Semi-flexible panels bonded to the roof (like mine) run considerably cooler (maybe 10% more efficient when hot?) because the steel roof conducts heat away from them and down into the cabin sides, but the roof itself will be hotter than with flat panels above it, even more so compared to having tilted panels shading it -- swings and roundabouts as usual with boats... 😉

 

(we do cooling analyses like this all the time at work, and the results are often not what "common sense" predicts...)

[gbclive]

If it gets really hot, I cut out pieces of foil type of emergency blankets and stick them to the inside of windows facing the sun with bits of electrical tape. It’s a bit of a faff, but the foil is cheap as chips and translucent enough to still be able to see out, although it’s like wearing sunglasses in doors, so not good in the evenings etc. 

 

My understanding of why this works so well is because of the greenhouse effect whereby the incoming short wavelengths of visible sunlight pass through the glass which is transparent to it. This heats up objects inside the boat (or car, or house). These objects then re-radiate longer wavelengths of infrared heat which glass is somewhat opaque to, so the heat is trapped inside. I use the foil gold side out which reflects enough the incoming radiation to make a significant difference.

 

Example of the foil, £10 for:

Bramble - 10 Large Multi-Purpose Insulated Foil Emergency Blankets Individually Packed - 210 x 160cm

 

 

Edited September 16, 2023 by gbclive

[Tony1]

 

If I know we're getting a bad heatwave and it'll be glaring sun all day long, I will always head for shade. 

I've been in a few places where there are just a few 'straggly' trees, or the shaded mooring spots are taken. So you might have to travel a bit- or do a few locks- to reach proper shade, but it's worth it.

Ideally I'll look for a place where the trees overhang on both sides, and failing that I'll aim for a spot where the boat is at least shaded for the afternoon, when the heat really starts to build. But ultimately, even a few hours of shade is better than nothing. 

I'm happy to abandon most of the solar power for a few days to stay a bit more comfortable.

I tried cutting up a white bed sheet into window-sized pieces, and I hang them over the windows using button magnets. Looks awful but it seems to work ok. Mine are hopper windows, so I can also take them out to allow more air movement, if there is any to be had.

Also fans- at least one powerful fan, and maybe two, will be a real help. I tried rechargeable fans originally, but they aren't really that powerful, so I ended up with a 240v model. 

 

Edited September 16, 2023 by Tony1

[Michael Puusta]

6 hours ago, nicknorman said:

Presumably solar panels covering most of the roof and with an air gap between them and the roof will mostly keep direct sunlight off the roof and allow airflow and thus the roof will be at ambient temperature rather than egg-frying temperature.

I did think that might help as I'll be fitting three panels on pan and tilt mounts I've made and perhaps a roof box would also serve as a shade as well.👍

[LadyG]

7 hours ago, blackrose said:

I'm always surprised when people say they've painted their roof a particular colour and it sounds like they haven't used deck paint. I know others aren't necessarily single handed but I'm up and down on and off my roof a lot when I move and it's essential that surface has a good grip. You can add non slip aggregate to any paint colour of course but I see a lot of narrowboats with gloss paint on the roof and it just looks dangerous to me. You can't set foot on that stuff in the wet. The majority of accidents on boats are from slips and trips.

I've never ever walked on my roof but the only bit that has a bit of gloss, is sort of daubed on  has a bit of non slip as I've had others jump on the roof, confidently.

[Naughty Cal]

On the boat we always found having all of the roof hatches and port lights open enough to create a through breeze and keep the boat cool. It was a white boat though. 

 

On the van we have a roof hatch with a large 12v fan so we can open all 3 roof hatches and put the fan on which keeps the air moving and the van cool.

 

It has been 37-38 degrees for a week while we have been out this time and we always managed to keep it cool enough inside to be comfortable. 

[LadyG]

At night I can crack open the doors, with chains through interior handles and all the windows cracked open. Obviously i moor in a scrote free area.

My sliding hatch screams like a banshee if anyone ties to open it. 

[Tony1]

4 minutes ago, LadyG said:

At night I can crack open the doors, with chains through interior handles and all the windows cracked open. Obviously i moor in a scrote free area.

My sliding hatch screams like a banshee if anyone ties to open it. 

 

Just a heads up in case you've not been there, but as an example- Chester basin is infested with rats, so don't leave doors ajar at night if you stop there. I'm sure the same is true for mooring in most towns. 

 

[LadyG]

7 hours ago, DShK said:

I've been looking at motorhome AC. Realistically it'd need a generator going or shore power. Another potential concern is the high in-rush current that could overload your inverter. A "soft start" device may be the solution.

 

What I did during that 40C heat was cover the boat in wet white sheets/towels and keep them wet. The water evaporating keeps the boat cool 

 

 

You could just wear your towelling dressing gown, suitably damp.

[IanD]

35 minutes ago, LadyG said:

You could just wear your towelling dressing gown, suitably damp.

 

Or wear a swimsuit (or nothing at all...) and spray yourself regularly with one of those little pump-up garden sprayers filled with water. Works brilliantly...

Edited September 16, 2023 by IanD

[DShK]

34 minutes ago, LadyG said:

You could just wear your towelling dressing gown, suitably damp.

How did you know about my towelling dressing gown? Have you been spying on me?!

[LadyG]

47 minutes ago, Tony1 said:

 

Just a heads up in case you've not been there, but as an example- Chester basin is infested with rats, so don't leave doors ajar at night if you stop there. I'm sure the same is true for mooring in most towns. 

 

Omg.

I've seen some folks with inverted filter funnels on ropes, i think I'd do that if long term, but I usually moor the bow quite tight,  and my cat flap door is missing due to feline abuse!

Edited September 16, 2023 by LadyG

[beerbeerbeerbeerbeer]

I think rats/rodents will (generally speaking) only invade an unoccupied boat. 
 

The only time I’ve had them aboard is when I’ve left the boat countrified while I go away. 
They soon left when I returned. 
 

 

 

[Tony1]

1 minute ago, LadyG said:

Omg.

I've seen some folks with inverted filter funnels on ropes, i think I'd do that if long term, but I usually moor the bow quite tight,  and my cat flap door is missing due to feline abuse!

 

They can get into surprisingly small gaps- I left a bag of rubbish in the cratch overnight instead of taking it up to the bins, and it was gnawed through and spilled by the rats- and there was a single loose button fastener on the cratch cover.

I saw them swim away and jump into a GRP boat moored behind me one night when I scared them off the bank, and there were many nights I saw them hanging about the place or running along the roofs of nearby boats.

I have a feeling they dont want to set up home the way mice do, so they probably wont stay around (although I think they had made a home in that GRP boat). But my plan was just not to let them in at all. I covered all potential entry holes, but I wouldn't be surprised if they can even get in through mushroom vents. 

On the plus side, you never hear people talking about having rats aboard, so it seems they just visit and then bugger off.