Dark or Light Hull - Is the Rumor that it Makes a Difference True ?

[Efraim]

“There are only two colors to paint a boat, black and white, and only a damn fool would paint it black.”

-NG Herreshoff

[speciald@ocens.]

A friend of mine had a black hulled Sabre in Florida. When you walked by the boat it felt like someone was aiming a heat gun at you. My hull is colored with awlgrip "Moon Dust"; its the color of the Chesapeake Bay "mustache" so dirt doesn't show. It is the fourth boat this color.

[rourkeh]

The choice of paint colour is going to have a very small impact on the temperature inside your hull in less it is made of a sub-standard laminate.
The last 2 boats we owned were 1. 51' painted white. And 2. 60' painted dark blue. We used both boats from a home base of Ft Lauderdale and spent most of our time south of there. I could not tell the difference in internal temperature between the 2 boats. I am sure if I did a study and measured temperatures the blue hull would be marginally warmer. But in real world usage did I ever walk down below and go "damn this blue hull is like an oven" NO. We currently have a 44' sailboat (white hull) that we are in the process of painting dark blue, and believe me if I thought it was going to make the boat a lot hotter down below I would be staying with white.
Like many things you will hear alot of disinformation from people who are passing on unfounded rumor, speculation, or "facts" with no firsthand experience.
You like blue. Paint the boat.

[GordMay]

Originally Posted by rourkeh

... believe me if I thought it was going to make the boat a lot hotter down below I would be staying with white.
Like many things you will hear a lot of disinformation from people who are passing on unfounded rumor, speculation, or "facts" with no firsthand experience ....

In my first hand experience (neither unfounded rumour nor speculation, and certainly not disinformation), dark hulls are warmer than light ones, and dark decks are hotter than white ones.
The theories substantiate and explain this experience.

[Mike43]

I know this thread is about boat colour and it morphed into heat transfer. Here is my 2c worth.

A bushies trick was to lay a blanket? or 2 over the cabin and keep it wet. Evaporation being the 1st principal of refrigeration theory. Of course if your boat is the size of the Queen Mary you are going to need a lot of blankets or whatever. Another is to sprinkle down your sheets (no, not the ones with the knots in 'em)If you get to sleep before they dry out you're cool. As in "cool dude"

PS I do have 1st hand experience of this and have found it very useful.

[steve_hendry]

Another bit of first hand experience--my previous boat, an Irwin 32, was white from the factory, but I painted the hull Brightside Sapphire Blue. The boat was kept near Baltimore, on the same creek as I now keep my current boat. The effect of the darker hull was to cause a repair I'd made with epoxy on the hull interior to peel off.

[colemj]

Originally Posted by rourkeh

Like many things you will hear alot of disinformation from people who are passing on unfounded rumor, speculation, or "facts" with no firsthand experience.

As I stated in the first sentence of my post, I have first hand experience and was relating it as fact.

If you have an insulated hull (and some core materials can provide insulation value) then your boat will not be effected by color as much as a solid laminate hull with no insulation.

Mark

[Joli]

We went from dark blue to white. When the boat was blue the hull side facing the sun was probably 140 to 160 degree f. When you opened a cabinet door on the sunny side the heat would roll out, the inside of the cabinets was maybe 140degree f.

With the boat painted whit is much cooler. If you touch the side of the hull facing the sun it feels like the ambient temperature of the air. The boat is much cooler inside also.

Finally, if the boat is not laid up for a dark color and you paint it a dark color the heat can cause print through.

Good luck and consider using an acrylic uerathane so you can repair the paint further down the line.

[S/V Illusion]

Common sense seems to get lost every time someone asks this question. Dark(er) colors absorb heat more so than does white. We all know that. The issue is how that affects ambient interior temperature and we also need some common sense here too. If the boat is well ventilated or air conditioned, the effect is negligible and you'll never know what the exterior color is unless you looked.

About the only thing with which most of us can agree is that boats should be pretty.
Since most of us statistically don't buy (or like) vanilla cars, it is also a reasonable conclusion that the only reason vanilla boats are most prevalent is cost, not aesthetic appeal.

If you like a colored hull, do it and forget all the BS.

[GordMay]

Originally Posted by Joli

... Finally, if the boat is not laid up for a dark color and you paint it a dark color the heat can cause print through.

Indeed.

[rebel heart]

Originally Posted by Efraim

“There are only two colors to paint a boat, black and white, and only a damn fool would paint it black.”

-NG Herreshoff

I came in here to post this.

[rourkeh]

That is the second mention of the Herreshoff quote. The guy quoted started building boats in 1863. Black and white WERE the only colours available. Not very relevent to the discussion of painting a boat in 2010

[markpierce]

I'm planning to have my boat's hull painted jade mist green, a very dark green. But then the hull is steel and the interior is insulated. Surfaces exposed to human touch (deck, exterior superstructure sides, and saloon roof) will be egg-shell white. Pilothouse roof will be bright yellow (for visibility) and the forward-cabin roof will be very light yellow to reduce glare.

[GordMay]

Originally Posted by rourkeh

That is the second mention of the Herreshoff quote. The guy quoted started building boats in 1863. Black and white WERE the only colours available. Not very relevent to the discussion of painting a boat in 2010

What's true often remains true, even over long time frames.

He also said something to the effect that "anyone who feels the need to stand upright aboard a sailboat, can go up on deck."

Pithy observer, that Nat.

[garymcg]

Originally Posted by heatherbrie

True, that's the theory, but theoretically, dark surfaces would also then radiate more heat at night, which would cool the boat.

I know how conventional wisdom permeates among sailors (we're all guilty!! ) and was wondering if anyone who has sailed with a dark hull and a light hull in the tropics has actually noticed any difference.

I wanted a flag blue hull until I got aboard a flag blue hulled boat right after stepping off a white one. It was easily 10-15 degrees hotter below, these boats were right next to each other.

This was in Chicago in the summer, never mind a blue hull in the tropics. None for me thanks...