Boats. Why is GRP...

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Simpo Two

Original Poster:

88,929 posts

280 months

Thursday 24th April
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...nearly always white? I'm sure it could be any colour, but 99% of boats are white. Why is that?

Rough101

2,697 posts

90 months

Thursday 24th April
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It doesn’t show up ripples as badly, and it’s reflects sunlight.

Simpo Two

Original Poster:

88,929 posts

280 months

Thursday 24th April
quotequote all
Rough101 said:
It doesn’t show up ripples as badly, and it’s reflects sunlight.
I'm not sure reflecting sunlight is a bonus, it can dazzle the driver!

sherman

14,381 posts

230 months

Thursday 24th April
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You cant see the scratches if its white all the way through.
White GRP has a uniform colour.

Simpo Two

Original Poster:

88,929 posts

280 months

Thursday 24th April
quotequote all
sherman said:
You cant see the scratches if its white all the way through.
If the colour is only the gelcoat, yes. Is it not possible to have, say, blue all the way through? Chuck some blue dye in it, no?

Arnold Cunningham

4,252 posts

268 months

Thursday 24th April
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Yes. But if scratch is that deep, fix it

simon_harris

2,085 posts

49 months

Friday 25th April
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Simpo Two said:
sherman said:
You cant see the scratches if its white all the way through.
If the colour is only the gelcoat, yes. Is it not possible to have, say, blue all the way through? Chuck some blue dye in it, no?
You can just an easily pigment the resin as well as the gel coat. I suspect there is some other reason why boats are mostly white and it has nothing to do with the material they are made from.

rolster

96 posts

100 months

Friday 25th April
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A previous reply on reflecting sunlight is the most accurate, as its to try and prevent all the sunlight's energy increasing the temperature within in the hull space.

You will find on most vessels operating in higher latitudes that their hulls are painted a dark colour such as blue, or black to absorb any heat from the sunshine. This reduces significantly the heating cost inside the vessel and becomes even more important with larger commercial vessels.

For larger commercial vessels the exposed accommodation blocks and engine casings are usually painted white to reduce the heating effect of the sun, in fact in areas of decking which are painted in green or reds then the insulation under these areas has to be double the thickness of the areas painted white to try and reduce the heat transfer and extra air conditioning capacity is usually directed to the living spaces beneath them.

This is important in this day and age on commercial vessels to reduce the load on air conditioning and fan cooling of spaces to reduce the amount of fuel consumed. I expect this will also translate to smaller yachts as those say in the Caribbean and Mediterranean would not want their air conditioning or cooling fans running all day in the summer and the associated fuel bills which come with them. For the manufacturer of these yachts, they get to reduce the thickness of the hull insulation which increases the internal living and working areas in Yachts which again has significant commercial cost savings when constructing the vessels all down to the colour used.

I see these days the usual YT channel family sized yachts are fitting solar panels, inverters and battery banks in an effort to save fuel usage, but these are significant investments for these smaller vessels.

OutInTheShed

11,249 posts

41 months

Friday 25th April
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White is popular for yachts, whatever they are made of.
It's a good choice for a wooden boat to minimise heat from the sun shrinking planks etc.
It tends to make the boat look bigger than other colours.
Darker colours show imperfections in the shape much more.

GRP gelcoat tends to degrade in sunlight, the surface goes white or chalky. This doesn't show too badly on a white boat. On a coloured gelcoat it quickly looks awful. Such boats need a lot more polishing to look good. They tend to need painting at some point whereas there are plenty of 40 year old white GRP boats looking OK.

Some boats are built with racing in mind, there are 'tactical' reasons for having your boat the same colour as everyone else's.

A lot of hulls are not built to order so a coloured gelcoat becomes an expensive option.
If you make a dark blue hull from a mould that makes white hulls, the blue one will show imperfections in the mould surface and shape.
Choices other than white go in and out of fashion over the decades, boats are long term items, the colour that seemed a good idea 20 or 30 years ago can make a boat very hard to sell now.
So some of the boats moulded in different colours eventually end up painted white.