Should we use antifouling paint on a boat built for a single atlantic crossing?

[Codys93]

Hey everyone,

I'm on the UBC sailbots team in Vancouver, British Columbia. We're designing and building a fully autonomous, unmanned sailboat to attempt the microtransat challenge (The Microtransat Challenge). I've been assigned to investigate the pros/cons of antifouling paint and whether we should use it on our hull. If you have and experiences/knowledge that would be beneficial, please let me know! I have a few general questions:

What kind/amount of buildup can we expect on our hull if the crossing takes us 2-3 weeks?

Also, does the paint significantly increase the drag of the hull?

In your opinion, is it worth putting the antifouling paint on our hull.

Thanks for helping out!

[Ex-Calif]

You won't get any appreciable build up in a single ocean crossing. The critters that attach are more prevalent in warmer shallow waters where their food supply is more abundant.

A hard smooth surface will be more hydrodynamic. Racers rarely use ablative paints.

It looks like the boat will be 4 meters maximum, I wouldn't overthink this.

[barnakiel]

I would definitely apply some kind of hard racing antifoul. Stuff grows and slows you down.

b.

[deblen]

North Atlantic crossing .You should have negligible growth in 3 wks.Too cold.
However,if money is no object,paint it with a hard racing a/f paint.
Where are u leaving from?

[a64pilot]

I'd paint it, things don't always go as planned

[Hydra]

I would apply hard, non-ablative antifouling paint and polish it, because hull roughness causes more relative increase in drag on slow, short-LWL boats than on fast, long- LWL ones. The slightest trace of fouling causes an appreciable speed loss on a short hull.

The racers who don't paint their hulls pull them out of the water and wipe them after each day sailing.

Alain

[Nicholson58]

Agree with the others. Hard & smooth. You will not experience hard growth of calcium critters in that time frame. What you will see is algae growth. Consider that a 1/2 mm thick moss means that your hydrodynamics is screwed up. Since friction of fluids along surfaces starts with the material next to the hull (or pipe ID) at zero speed difference, you are dragging a layer of water 1/2 mm thick with you. Calculate that mass.

[minaret]

Apply VC17m and wet sand to 1000 grit.




Jamestown Distributors

[MarkJ]

Dunno about the north Atlantic route but the tropical route you get these little buggers on within your 2 to 3 week crossing




Pain in the boat butt and slows you down cos of the size of them.

[Terra Nova]

Originally Posted by barnakiel

I would definitely apply some kind of hard racing antifoul. Stuff grows and slows you down...

Originally Posted by a64pilot

I'd paint it, things don't always go as planned

This.

You can't know how long or where this trip might take you, what unforeseen delays might occur. A proper racing bottom will give maximum performance for the duration of your trip.

[sy_gilana]

Don't know about your paint question, but I have severe reservations about your autonomous vessel. I think they should be prohibited.

Tell me how you would handle this scenario....

A family sitting in a liferaft after their boat sank. They are out of water, food, and near death. One night they see your vessel's lights and fire off their last flare. What will your boat do?

Another scenario....

A vessel encounters yours at night, near land. Your vessel does not make a decision according to Colregs. The other vessel makes a decison that results in an allision.

Who is responsible?

I think the IMO should be involved.

The sea is not a playground.

[colemj]

For perspective, these boats are only 1.2 meters long. It doesn't seem likely that they would be mistaken, or even seen, by someone in a liferaft (BTW, there hasn't been a liferaft survival situation in many decades), and unlikely to be a collision problem in a Colregs situation.

Mark

[Ex-Calif]

Originally Posted by sy_gilana

Don't know about your paint question, but I have severe reservations about your autonomous vessel. I think they should be prohibited.

Tell me how you would handle this scenario....

A family sitting in a liferaft after their boat sank. They are out of water, food, and near death. One night they see your vessel's lights and fire off their last flare. What will your boat do?

Another scenario....

A vessel encounters yours at night, near land. Your vessel does not make a decision according to Colregs. The other vessel makes a decison that results in an allision.

Who is responsible?

I think the IMO should be involved.

The sea is not a playground.

But the sea is vast...

This is a competition and it appears there is a chase boat. I am presuming the steering and trimming is done by radio control.

i.e. these are large "toy" boats we are talking about.

Longest permissible is 4 meters. You should click his link to check out the rules...

[gjordan]

Unless you are trying to make it look like a miniature yacht, put the hard bottom paint clear up to the toe rail. On my first crossing, I got no barnacles below the water line, but had a real garden of them above the boot top where the stern wave was always higher than the bottom paint. That was 3 weeks in warmer water, but only a couple of gooseneck barnacles will completely ruin your venture. Good Luck. ______Grant.