Does anybody know the history of why the use of long-chain polymers was made illegal for racing sailboats?

If you are referring to the use of long-chain polymers as friction reducing agents, it goes back to the America's Cup.

I believe it was one of DC's boats in the late '80's that had an injection system that pumped a goo onto the hull surface while sailing.

Not sure of the actual reason given for their banning back then, but they are banned in most one-design classes due to their perceived cost and "unfair advantage" given to those that use them.

Hi Mary,
Boundry layer theory tells us that on a boat hull going through water there is a layer of water that is stuck to the hull, called the sub laminar boundry layer, and it moves with the hull. Therefore all of the velocity gradient between the water and the hull due to boat speed takes place between layers of water. There is a shear gradient in the water, the boundry layer, near the hull. The innermost layer of water is stuck to the hull and therefore is moving at boatspeed with the hull. The outermost layer of boundry layer water is not moving and has a velocity of zero. Between these two layers of water is where all the shearing occurrs. This is where the friction/viscous drag occurrs. If we could lubricate these layers of water where the viscous drag is occurring , we could reduce the hull drag. A long chain polomer like liquid soap will lubricate the water and reduce viscous drag. As Racing sailors we could come with all kinds of spray bar devices to get the long chain polomer in the water just in front of our boat and make it go faster. We would leave behind a trail of bubbles and poluted, soapy, water. I think everybody sailing in the same viscousity water is part of the fairness of sailing.
This sublaminar boundry layer of water that is stuck to the hull cannot be made to go away and reduce drag. Wax/polish won't do it. Teflon won't do it. Owl ---- won't do it. If you were a water molecule and a boat hull passed close by, you would swear that boat hull was made of water because that is the covering on the hull you saw pass by.
Bill

Mary

The prohibition to use oil or other substances to reduce friction is VERY old. It was there in 1973 when I first read the rules and I think it might have been there when the rules where first written, for the trick itself is even older.

The oldest book I read about it was from Jules Verne (XIX century) - a boat's captain ordered to dump oil to calm the waves and facilitate the entry through the reefs.

Cheers,

Mary,
In my real job I supervise submarine design and research for the Navy. There was quite a bit of experimintation in the 60s and 70s related to torpedos skin friction. I know of at least three approaches that were looked into for reducing skin friction:
1. Long chain polymer injection into the boundary layer.
2. Compliant hull surface. This emulates how "spongy" dolphin skin complies to the little turbulent eddies in the boundary layer - delays seperation of the layer from the hull.
3. Using a ring of small holes in the bow to either blow or suck air into the boundary layer and alter the flow mechanics.

It is interesting to note that the polymer injection actually takes a very small voulme of fluid. The stuff is so slimey, a little goes a long way.

Kevin

Mary

Let me offer a different perspective. I was in Newport in 1970's. I was listening to some of the big name skippers BS'ing and drinking after a race. The conversation I remember is:

" just anouther damn nuisance. They tell me if it works, it will work about evenly for all boats. So, everybody will have to do it and nobody will have an advantage. It will end up just being anouther thing we have to worry about. So let's just ban it now and not worry about it"

Here is why I asked the question: I read a long time ago that the reason air pollution from diesel fumes is more dangerous than from gasoline fumes is that diesel spews out long-chain polymers into the air.

Now we have a motorhome with a rear-engine diesel, so the exhaust fumes go directly back onto our boat hulls whenever we are traveling, making the hulls all black and yucky. Our first instinct was to wash them, but another instinct is to avoid unnecessary work, so I came up with the idea that we should not wash the hulls because maybe they have long-chain polymers all over them, making them ugly but fast.

What do you think? Is that possible? If so, maybe our boats are illegal.

(P.S. Before somebody suggests it, yes, we do plan to run the exhaust pipe up to the top of the motorhome so our boats don't keep turning black.)

Your boats are not illegal nor faster - just dirty Spread a common detergent in the bows before hitting the road. The fumes will adhere to the detergent but the detergent is easy to remove - with the smoke particles.

One of the best for this purpose is polyvinyl alcohol. When injected into the water right at the stem of the boat it reduces thickness of the attached boundary layer and therefore reduces drag. But maybe cats go too fast for this to spread out and be effective.

Luiz,
Rick is going to be sorry to hear this, since he has won two regattas with his dirty boat. And I am sorry to hear it, because I am usually the one who has to wash the boats.

Mary,

Rick won due to his own merits. Lubricating the hull does not help significantly.

As Bill wrote, the lubrication is effective to reduce friction between water layers, not between the hull and the water.

Cheers,

Mary,
Could your source have been talking about long chain hydrocarbons rather than long chain polymers? Long chain hydrocarbons would fit with the diesel truck exhaust fumes much better than long chain polymers.
Bill

Go back to your college chemistry text books.

Long chain hydrocarbons are long chain polymers. Take, for instance, polyethylene:



A long chain polymer / hydrocarbon. Which, coincidentally is what your Waves are made of.

What is coming out of the tailpipe of the motorhome is neither. It's soot. Mostly carbon. Which happens to stick very well to the waxy polyethelyne hull surface of the Wave.

Polyvinyl alcohol (mentioned earlier) is another long-chain hydrocarbon that when cross-linked with borate ions, forms something familiar to most kids - Slime.

{whoa - somebody didn't like me stealing their bandwidth}

You have a good point with all the rhetoric flying around. Chemically speaking- a "polymer" is merely a repetitive unit of the same molecular structure comprising a large molecule. Their chemical stability is both a blessing and a curse-environmentally speaking. The word "polymer" has been overused in so many popular products that its' intended meaning has been blurred. I think it is generally viewed as our scientific progress in making things lighter and more resilient. I'd still opt to clean the soot from my tailpipe off my boat and start on the favored side of the line.

you know this means that Rick will no longer have an excuse as to why he (or..er...Mary ) is not washing the boats.

You guys are all so incredibly knowledgeable!

I am interested in what Luiz said about about protecting the hulls from soot by putting detergent on the bows when traveling. But I think it would take more than just the bows.

SO, if I smear Joy dish detergent all over the boats before we hit the road, will all the black stuff wash off when we get to our destination?

AND if there is no hose available to wash it off on land (as there usually is not), is it legal to put the boat in the water with Joy all over it, getting detergent and suds into the water?

AND will having Joy all over your hulls make your boat faster, at least until it all washes off?

Mary, Putting liquid soap to ease in cleaning soot is a proven thing. We have been showing our Boy Scouts how to do that for years when camping out. When cooking on a campfire put some soap onto the bottom of the pots (it dosen't take much) and the cleanup is much easier. That also works on pots used on a propane burner (down here we use that to cook crawfish). You would think the soap burns off, and some does but it leaves a film between the soot and the metal.

Just FYI.

Clayton

yeah - except that having liquid soap smeared all over your hulls during a 1200 mile trip will attract every piece of dirt, dust, and debris to your hulls. I can only imagine what they would look like when you finally arrive. Leave it on long enough (i.e. the trip home and leave the boat stored) and the liquid soap, while still water soluble, turns to a thick glue like substance. We build machinery in production plants that run soap and dried liquid soap is a major problem with moving components.

That's why I said- polyvinyl alcohol. It is a masking agent like masking tape when I make beautiful new carbon fiber rudders! But when sprayed it dries to a thin dry green skin on fiberglass-- and washes off quickly. No gumming up.
Rick White? Wash a boat? Heaven forbid---When did that ever happen?

Where do you get this spray-on polyvinyl alcohol?

And as far as Rick not washing hulls, why do you think he married me? He knew that I had been trained by my father, from an early age, to wash the bottom of the boat every time before racing. When we had our Lightning, which was kept in the water all season, we had to use a long-handled scrub brush to clean the bottom every Sunday before racing. When we got our Shark catamaran and dry-sailed it, we had to wash the hulls with detergent every Sunday.

With both boats we pretty much always won, so I figured it had something to do with washing the hulls. Maybe I was just being brainwashed, by my father and later by Rick, but I have always been convinced that washing helps. I have washed more hulls in my day than probably any living sailor.