Black hull in Med

[westernman]

Thanks for a lot of interesting remarks.

My partner thinks black would be the bees knees since having seen Marigold (gaff cutter yacht from 1892) at St Tropez a while back.

It would be just the hull - the decks are of course untreated wood (and they are too hot to walk on bare foot sometimes).

 

[Woodlouse]

Marigold suffers horribly from having a black hull. They have pale canvas skirts that they rig up to protect the hull from the sun and at least once a day wet down the topsides to stop them shrinking back too much. It may look good, but it's not really a good idea. Partidge has none of the same problems due to being white.


I think it was Nat Herreshoff who claimed 'there are only two colours to paint a boat, white and black. And only a fool would paint their boat black.'

 

[saltwater_gypsy]

Forget the physics lessons, we painted our decks (GRP boat ) a medium/light grey in the non slip areas with non slip deck paint in the Med and you could not step on them in bare feet they got way too hot. The white non slip areas were easily walked upon even at the hottest part of the day, so I disagree that colour makes no difference to heat absorbtion, I can simply state that in practical use it does !!

Ah well sir, that will be your reflectivity difference between gelcoat and paint you're talking about now.......not a lot is known about that either!!!!

 

[rascacio]

Does it matter

Ah well sir, that will be your reflectivity difference between gelcoat and paint you're talking about now.......not a lot is known about that either!!!!

What more physics ? Whatever is known or not known about it is really irrelavent, the fact of the matter in practical terms is that a darker colour gets hotter than a lighter one. Anyone can check this out in 10 minutes in the Med sun if they've the mind to !!

 

[aquatom]

Its the shiney metal bits that get really hot. I left my spanners out in the sun this summer and had to wear gloves to pick them up again.

 

[Wishsong]

You canny beat the laws of physics Captain!

Dispite all the personal experiences quoted, colours only reflect or absorb visible light differently. Its infrared that heats your boat up, and it doesn't care much what colour it is. Keep it shiny and you'll reflect the heat whatever the colour. Metal gets hotter because its a better conductor of heat.
My current hull is black and beautiful, and though its a pain to polish it doesn't get any hotter than all the AWB's I've had in the past.

 

[Bosun Higgs]

I've seen several boats now with dark coloured hulls and that have been to the med and in every case there has been some shrinkage of the laminate that has caused the texture of the underlying cloth to show through. I was warned about this by the boatbuilder when discussing ordering a new boat from Northshore and certainly they had a Vancouver 34 pilot in their yard showing excatly that effect.

 

[Resolution]

Some years ago a customer for a large Jeanneau wanted the hull painted black. Standard Jeanneau hulls were all white gel/GRP and some for the UK were painted darkish blue. The factory at first refused to paint in black, and only conceded when the customer agreed to stand the consequences if any.

Well, after one English summer the transom (sloping to catch the sun?) was bubbling all over the place and had to be re-glassed and repainted. Never happened on the white boats.

So don't do it!

 

[whipper_snapper]

Our boat was ashore on the Kenya coast undergoing a major refit. There was a period when it was painted with a hi-build, matt, grey undercoat before the top coat went on. During that time I was working below doing a complete re-wire and refitting gas etc. Conditions were downright dangerous. Sweat was pouring off me and pooling on the bilge. I was guzzling water but I still couldn't hold a screw driver because my hands kept cramping-up, I kept having to stop, prize my fingers off the screw-driver, crawl out and go eat some salt.

As soon as the shiny white paint was put on the improvement was obvious.