Are dark hulls hotter?

[Eleuthera 2014]

Early on in this thread, I reported tests done by Oyster on 2 identical boats, one dark blue and one white.

The temp was considerably higher in the dark blue hull.

Further to that point, apparently, Oyster is reluctant to guarantee a dark painted hull because the paint separates/flakes from the undercoat due to temperature differential.

It is basic physics folks.... just like solar water heating systems are black to absorb more heat.

[Julie Mor]

Originally Posted by Eleuthera 2014

Early on in this thread, I reported tests done by Oyster on 2 identical boats, one dark blue and one white.

The temp was considerably higher in the dark blue hull.

Further to that point, apparently, Oyster is reluctant to guarantee a dark painted hull because the paint separates/flakes from the undercoat due to temperature differential.

It is basic physics folks.... just like solar water heating systems are black to absorb more heat.

The devil's advocate in me asks, "If dark surfaces are such a problem, why does Oyster install teak decks on their boats?"

[Eleuthera 2014]

Originally Posted by Julie Mor

The devil's advocate in me asks, "If dark surfaces are such a problem, why does Oyster install teak decks on their boats?"

Because a small minority of very rich yachties don't care about all the aggro.. they pay minions to fix the problems. If you use common sense, teak decks are out.

You enjoying freezing in CHI???? Imagine being in the Bahamas on a nice Amel....

[Conall63]

While building my steel trawler, with it's green hull, I noticed just how hot dark steel can get. The boat was hauled to the launch site in two pieces, and due to the order of how things were to get finished, part of the hull had not been insulated so we could fit and weld the wheel house to the hull. When the sun was shining on those November days, the uninsulated, green painted area of the hull, would get so hot on the inside one could not keep your hand on it for too long. An inch away, where we had 2"- 3" of closed cell spray foam, the hull foam was cold.

The boat is heavily insulated with two to three inches of closed cell spray foam, so no heat is felt radiating through the green hull sides. I could only guess how hot, an uninsulated dark hulled, boat would get.

[lesterbutch]

I don't think you can debate dark hulls transferring more heat. It is physical fact that dark surfaces absorb heat faster than light surfaces. That said it then comes down to insulation! This is something that many boats dont have, and it's costly and difficult to install while maintaining an attractive interior. Therefore you are willing to put up with the added heat or paint your hull a light color.......

[Sundae Driver]

Originally Posted by robert sailor

If you made your choice based on visibility (safety) then you would choose white. Black is the worst color for being seen.

I made my choice; I pretend I am invisible and ride accordingly. I adjust my lane position and speed to avoid occupying the space in the path as any left turning vehicle might use to intercept and collide with me (on average those drivers take out 3/4ths of the riders) and pay high attention to those behind to prevent being rear ended at stops; I leave room to dart between cars if needed. If I wanted to dress like a roadway worker, I could do that and it would be more conspicuous and better in terms of increasing my visibility to others. But one would still invisible to anyone that is not actively paying attention, such as texters.

Kindest,

Sundae

[lesterbutch]

Originally Posted by Sundae Driver

I made my choice; I pretend I am invisible and ride accordingly. I adjust my lane position and speed to avoid occupying the path as any left turning vehicle might use to intercept and collide with me (on average those drivers take out 3/4ths of the riders) and pay high attention to those behind to prevent being rear ended at stops; I leave room to dart between cars if needed. If I wanted to dress like a roadway worker, I could do that and it would be brighter and better in terms of visibility. But one would still invisible to anyone that is not actively paying attention, such as texters.

Kindest,

Sundae

Am I missing something, I do ride a motorcycle but, I thought this was about boats! Specifically boat hull colors.

[Pelagic]

All else being equal, the empirically proven answer is YES
The rest is just side notes on mitigation

[Sundae Driver]

Originally Posted by lesterbutch

Am I missing something, I do ride a motorcycle but, I thought this was about boats! Specifically boat hull colors.

The use of helmets in the summer means they are hot. There is a similar theme about color and visibility for wearing one over the other which parallels hull color. What you may have missed is that because helmets have energy absorbing materials (with properties similar to insulation) the inside temperature wasn't different. The same would likely be true for well insulated boats, one assumes.

Kindest,

Sundae

[builder dan]

I have just painted my steel yacht dark blue it used to be white the hull is insulated,its summer over here now and I cant tell any difference inside.The outside is warmer though.Looks a lot sharper now.

[PortClydeMe]

Originally Posted by Eleuthera 2014

Early on in this thread, I reported tests done by Oyster on 2 identical boats, one dark blue and one white.

The temp was considerably higher in the dark blue hull.

Further to that point, apparently, Oyster is reluctant to guarantee a dark painted hull because the paint separates/flakes from the undercoat due to temperature differential.

It is basic physics folks.... just like solar water heating systems are black to absorb more heat.

That all makes very good sense, and I'm sure Oyster's findings are true.

And with that said, I'm intensely salivating for a dark, flag-blue hull, preferably around 42 feet long -- tropics, or not! You only sweat to death once.

[boatman61]

Its all down to Mind over Matter..
If you don't mind.. it don't matter..

[PortClydeMe]

Wife: "Honey, isn't a little hot in here today?"

Me: "No, not at all. It's a little sunny outside, but us folks from Maine always lounge around the cabin each October in Bermuda shorts & a tank top while enjoying our autumn gin and tonics."

[Julie Mor]

Originally Posted by PortClydeMe

That all makes very good sense, and I'm sure Oyster's findings are true.

In my empirical testing , which included one blue-hulled Oyster, the results don't support the belief a dark hull in sub tropical waters results in a hot interior.

It was about 90 degrees and sunny in Ft. Lauderdale when we boarded an Oyster. The broker opened the companionway doors and I stepped below, completely expecting to be gagged by the heat, as I had many times before on white-hulled boats. I was surprised to find it was actually cooler below than outside and all that was running was a dehumidifier and a fan.

As far as the paint delaminating, I saw no evidence of this. And this boat had been in south Florida most of its life. I don't know when the hull was last painted but I do know it was more than four years ago.

[Rohan]

Originally Posted by robert sailor

If you made your choice based on visibility (safety) then you would choose white. Black is the worst color for being seen.

Then wouldn't you choose bright orange for safety? It's a horrible color for a boat though.