Paint Colour

[Steven Prince]

Ok, As some of you may know already I'm designing my own boat. My problem is I want to paint the hulls (its a catamaran) Black. This i know is likely to cause issues with certain materials, for instance a foam cored hull. Do people think I'd have the same problem with a wood epoxy constructed hull. Any help would be appreciated as I really don't want to have the hull white like nearly every other boat.

I do understand that if i do the hull and deck black that the cabin temp will be like an oven in the hotter climates which is why I will look at using white for the deck.

[Lodesman]

Steven,

I wouldn't think that shiny black paint on the hull sides would be too worrisome, but could definitely see how the boat would get excessively hot, if you painted the decks black. You certainly wouldn't want to walk around in bare feet, which in my mind, goes against the philosophy of cruising. You might consider silver paint on the decks - it goes well with black. You should check with the epoxy manufacturer to determine how much heat your wood/epoxy hull could withstand. Then you could always experiment with a test panel on your hottest, sunniest summer's day to see how much heat is absorbed by the black paint.

Good luck with your research.


Kevin

[Steven Prince]

Kevin,

Thanks for the input. Think i'm definitily going to have a different colour for the deck, but if i can have black for the hulls it will be great.

What are your thoughts about the colour red, do you think this would attractto much heat. Thinking of going with a black white and red colour scheme. The shade of red i'm thinking of is blaze red as seen on the original Rover minis.

Steve

[edboat]

If you plan to use your boat in tropical waters you might want to think about lighter colors. A dark color hull can make the interior very hot. The same can be said for the deck. Any color darker than white will be hotter. Take a digital thermometer to a marina and shoot the dark hulls on the sunny side. You will be amased at the difference. I am not sure that you can put enough insulation in the hull to make up for the heat.

[Steven Prince]

edboat

This is my biggest worry especially as where i live does not really allow me to experience how hot a cabin is that has dark coloured hulls.

I think i'm going to have to admit defeat, i've got a few years till the hulls will be fully constructed to do more researh tho.

[Lodesman]

Steven

I think you'd be better off with the red, than the black, as obviously less light is absorbed. Red will still absorb more light and therefore heat up more than lighter colours. Make a red test panel as well to see the comparitive difference with the black.

Kevin

[mikereed100]

Steven,

I think black and red are beautifull colors on boats. jThat said, and I apologize if I repeat myself, I believe it was one of the Herreschoffs who said "there are only 2 colors to paint a boat, white and black, but only a damn fool would paint his boat black". Not casting aspersions in any way, but I think that over the course of this project you will be confronted with innumerable hurdles to overcome, and I'm confident you will. My point being that it may be unwise to create issues where they can be avoided lest you tax your endurance. Maybe you could compromise by using black and red trim in strategic places to avoid that generic white look. Whatever color you decide on it's a beautifull boat! Best of luck.

Mike

[Pblais]

Navy blue is a popular color alternative to black. Consider it one off from black. A true Navy Blue is a very dark blue. That said in tropical climates the paint fades quickly. Dark green fades even faster. The pigments in the paints do weather differently and not uniformly across colors of the exact same paint type / brand. Even the best paint won't last as long as a white gelcoat. You might as suggested not paint the entire hull.

[MidLandOne]

Mid to dark linear polyurethane blues are said to have about 2/3 to 3/4 the life of white. I would assume black would be less again, especially in higher UV regions. And for a boat usually moored in a home marina the sunny afternoon side will degrade faster than the shadier morning side.

Probably not an issue for a well funded race boat campaign where repainting for other reasons is a common need, but maybe is for a cruising vessel.

[Fishspearit]

Our first boat was painted black when we bought it. Beautifully painted with Imron the year before we got her and started sailing south. By the time it was in desperate need of repainting 6 years later, we had decided to go with the rest of the herd(which I normally Hate doing!) and painted it white. With decent ventilation I never thought that interior living temperatures were that bad, even in the Caribbean, but the exterior lockers would get smoking hot, to the point where we had to severly limit what we stored in them. Clothes and paperwork ok, but no food, paint, electronics, etc. Despite how good it looks, our conclusion was that it's just not practical in an equatorial climate.

[David M]

Steven,
I used to run a boat that had a midnight blue hull which was almost black. At Latitude 38 north, the temperatures were not so extreme that it made any difference from a thermal perspective. I think boats with dark hulls look really good in fact. What I found most annoying about a dark hull is that they show every single imperfection and every single scratch in the hull. Done in Awlgrip to a mirror finish, dark colors looks really good! Sure looks better than the bleach bottle look.

I have to tell ya though, you will want to get that hull perfectly faired out if you are going to paint it black, otherwise you are going to see every last ripple and imperfection. Do it right though and it will look fantastic.

David

[Steve Kidson]

A couple of points to bear in mind:

1. The higher the gloss level and darker the colour, the harder it is to hide any imperfections, and as mentioned, the more that normal wear and tear will show up the scratches and bumps that inevitably appear no matter how careful we are.

2. The pigments in darker colours are broken down by UV at a much more rapid rate that the more bland, white, off white, beige, creme whatever......... Probably not so much of a problem at the higher lattitudes, but get closer to the tropics and topsides will be looking shabby quite quickly.

3. As most have mentioned above, the temperature below decks can quickly become unbearable, even in temperate weather conditions. I guess this is why they paint solar hot water units black.

I guess the alternative is to have the black hulls, and a genset to run an airconditioner. That way you can have the slick black hulls, and still be comfortable below

Fair winds

Steve

[Alan Wheeler]

If you are going to the tropics, Black is the silliest colour to paint the hull. We had Dark blue on ours and the heat was horrific. And we are not in the Tropics. We have just painted our hull White. Black would not only make the interior unbearable, but the heat would also greatly weaken the fibreglass. Of course, to what extent depends on what resin you use.
As for UV degradation, black is higly reflective of UV and most likely will last longer. Red is one of the worst at fadding. But it could be more to do with the what is used for the red dye than the actual colour.

[MidLandOne]

Originally Posted by Alan Wheeler

As for UV degradation, black is higly reflective of UV and most likely will last longer.

Black is actually highly absorbtive of UV - black is black because it absorbs all visible and close to visible wavelengths of light. Black plastics touted as UV resistant, eg cable ties, are black because carbon black is added (making them black) - the carbon black particles absorb UV preferentially converting the energy to heat so protecting the plastic.

Carbon black is also used as a pigment for black paints but I do not know whether it or UV stabilizers are used in marine paints such as linear polyurethanes, but I suspect not carbon black in black linear polyurethanes. Black paints protect substrates (eg the sealant holding car windscreens and marine glass in) because the black absorbs the UV preventing its passage to the substrate.

Getting back to paints - from the dim dark ages I seem to recall that white paint (UV stabilised) which reflects UV has better life in UV climes than black paint (UV stabilized) that absorbs. But it may be that black paint may protect itself in the same manner as black plastics having carbon black (and paint is a plastic).

Maybe if white paint is better resistant to UV that is why lots of plant exterior pipework, tanks, etc are painted white? But I may be wrong and would be very interested if anyone has some professional knowledge on this.

[Alan Wheeler]

Black is actually highly absorbtive of UV - black is black because it absorbs all visible and close to visible wavelengths of light.

Well maybe I am wrong but.... I have a friend in the US (from my old Acoustical engineering days) that does extensive work in the Laboratory with UV light spectrums and he has told me that once you get up into UV freq bands, UV in fact reflects off of black.
Now, I have said in that it is absobed by white, but I think in hind site, I am wrong with that part. And that os from a practicle standpoint Iexperiance everyday with welding. White can reflect off of our white surface in the welding class room and "sunburn" us if we are not protected.
When I was trained by epiglas 20yrs ago, the head paint specialist guy there was involved with Stienlager. Because of the sponser, they were asked if the entire boat could be painted red. He did tests and the report back stated the temperature of the deck would become so high in the tropics, they would most likely experiance structural failure. His conclusion was Red, Black and Blue were the three worst ofending colours. Now we did discuss this here some years ago and I can remember Gord in his usual excellent way replied with a list of colours and respective temperatures that they produced in the sun. It did show differences in what the Epiglass guy suggested, but it is possible there was a lot of info not told in the general conversation with me as against a spicific lab test.