Ship Hull Painting Question

it is typically better to paint from light to dark

I still gotta mask off the black though. better to paint the black first so it will be easier to mask off the other colors?

Craig

That's the way I have done it for years. You get a nice straighe boot topping that way. Use the edges of the tape you put down to cover the black to mask for the other colors. Pete

Normally this is true. But it is easier to get a neat "boot topping" by doing black/red/grey. The lightest first is applicable where a dark colour underneath would "shade" the top colours. In this instance its not as critical and, in fact, a slightly darker tone to the red maybe advantageous.

The way I would do it is this: First, paint the upper hull gray, going a little beyond the waterline. Then, mask the upper hull down to the top of the boot topping, and paint the lower part of the hull red. Finally, mask the lower hull up to the bottom of the boot topping, and paint your black stripe.

This way, you only have to mask twice, and you don't have the problem of trying to cover the black with the gray.

BTW, I've found that Floquil "Zinc Chromate Primer" (#130601) makes an excellent hull red.

Works for me and I keep winning Regionals with my ships.

You'd better paint the whole thing black, as black is hard to cover up without lots of coats. Personally I'd do grey first, red second, and black last. Consider black trim tape instead of painting.

A little OT, but Red Oxide primer makes a good red for merchant red bottoms.

Anti-fouling paint. Used to be mostly red-lead. Nowaday's anti-fouling paint comes in various colors... blue, red, green. Very expensive stuff. About $100 to $150 per gallon. Topside gray paint is a whole lot cheaper .. $25-$30 a gallon. When you're using hundreds or thousands of gallons to paint a ship, the cost difference adds up. Military ships are gray as a sort of camouflage. Merchant ships are often white (e.g. cruise ships) or black for visibility .. just what you don't want on a military ship. As for the stripe, it is to demarcate the two different paints. Without some sort of stripe to paint to, after a few coats, the water line and the boundary between the top and bottom paints would look like spaghetti on amphetamine. This is especially important as topside painting was often done at sea or in a calm anchorage.

Boris

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Just as a sidelight, the Titanic (and White Star ships generally) didn't have a separate boot stripe, whereas the Cunard ships typically had a white boot stripe. One of the reasons the Gunze Sangyo model of the Lusitania has a hull molded in white is that it's much easier to render the boot stripe that way. You just mask the scribed lines and paint the top of the hull black and the bottom hull red, leaving the boot topping in the white molded plastic.

WWII Italian ships apparently used a chromate green below the waterline.

Red happened to be the easiest color to achieve with anti-fouling coatings at the time they were introduced. Black boot topping came in around the time warships went from coal fired to oil fired to keep the oil slicks on harbor waters from making a grungy ring around the ship.

It came about due to oil fired boilers and the oily residue in harbor waters from fuel spills. Admirals didn't like the grunge line it left on their pretty ships.

Generally Flower class corvettes, civil registered Liberty ships and most WWII era merchant ships did not have boot tops.

CVN-65 originally had a green epoxy anti-fouling coating and CV-10 went into wartime service with no anti-fouling coating just the primer (apparently she had quite a beard when she went in for her first refit).

Depends on the specific red, but red oxide is a very popular marine paint. It is cheap, but very good protection. Similar to why barns are red. Red Oxide paint was very cheap, but very good protection.

I wonder if other, non-red-oxide bottom paints are red 'cause of tradition of red oxide?

Jim wrote:

The "red-oxide" if I recall, is not iron oxide, but lead oxide. Very toxic stuff and a decidedly ecological no no. I mentioned the price differential earlier. Bottom paint at $100-$150/gallon versus top paint at $25-$40 /gallon. So it is certainly not more economical to paint it all one color. Especially since the painting is done by sailors who would otherwise be playing craps or something. Also, while topside painting can be done anywhere without special precautions, (e.g., at anchor), bottom paint has to be done in drydock and requires special precautions because of the toxic nature of the paint. As for durability, nowadays, bottom paints are deliberately not durable. These paints are designed to be ablative. That is, they deliberately erode, taking the nasty little barnacle nymphs and red algae along with it. Both the navies of the world and the shippers are very sensitive to cost issues when it comes to painting ships (thousands and thousands of gallons) so they do it in the most economical way. It isn't a matter of style or tradition.

Boris

The single most important aspect of anti-fouling coatings on ships' bottoms is the chemistry that inhibits marine growth, everything else is secondary.

Most USN surface ships are red, subs vary from red to black. It's chemistry not color that's important.