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From the Epic website FAQ - Greg Barton

To wax or not to wax?

I'm often asked, will waxing my kayak make it faster? There are two schools of thought here. The first is that waxing will make the hull surface smoother, slipperier and faster. The other is that wax causes water to bead up on the hull and the added surface tension actually makes your boat slower. My experience has been that neither is true, but read on for some practical ideas on how to achieve a good fast surface on the hull of your kayak or canoe.

I'm always hearing tales of how a particular surface finish will make a boat faster. I remember way back in the '70's that a chemist told Olympic Canoe finalist Roland Muhlen that covering his canoe with Teflon would create a low friction surface and make his canoe faster. So Roland covered the entire surface of his canoe with Teflon film. While Teflon has amazing low friction properties between solid materials, it's similar in friction to most other materials between solid and liquid (or hull and water). Roland found no speed improvement, so removed it from his hull. But it did have one side benefit - he left in on the right gunwale, which provided an excellent rub strip for J-stroking! Such is the case with most other “low friction” surface treatments that I've seen. When tested, most of them make little or no difference in boat speed. I've only seen two things (so far) that make a significant difference in speed - and both have been banned by the International Canoe Federation for racing.

The first is a slimy polymer compound applied to the surface of the boat. This compound dissolves in the water, lowering the viscosity of the water next to the hull and reducing drag. As it dissolves it comes off until it is no longer effective (leaving contaminated water in your wake). The Polish national team used this material many years ago in international sprint competitions. They would warm up in one boat, then have a separate “race boat” with the compound applied to the hull. Just before the start, they'd change to their race boat, back into the starting blocks and sit on the line. During the early stages of the race, the polymer did its magic giving them a boost in speed. By mid race, the polymer was gone and they completed the race with no further advantage. But still - they had a nice boat length or so benefit (so I was told) in the first half. The following year, the ICF banned the substances and started requiring that all race boats be launched from a single dock. That dock has a race official with a sponge and a bucket of water. He sponges some water on the hull of each boat, checking to make sure there are no slimy substances.

The other item that really works is a “riblet” material manufactured by 3M. It is an adhesive backed plastic film with very fine grooves machined into it (similar to the grooves in a phonograph record). The size of the grooves is matched to the density of the fluid (water in our case) and the speed of travel so that the grooves dampen the turbulence of the water as the flow detaches from the hull. The grooves need to be carefully aligned so they are parallel with the flow of water over the surface. 3M donated some of this to the US national team in 1986 and we tried it on a few boats. I raced one of the boats in the heats and semifinals of the World Championships in Montreal, winning both preliminary races. However, I was “outed” by a bunch of kids. After each race, the top finishers are required to go to boat control, where your kayak is checked to ensure it meets specifications, including minimum weight. In order to get a consistent weight, the boats are dried with a towel before weighing. The kids drying the boats noticed that my kayak had an odd feel to it as they rubbed the towels over the surface. The towels seemed to “track” lengthwise down the boat, and had a lot of friction (and made a “zip-zip” sound) if wiped quickly across the grooves. Soon there was a whole crowd of onlookers and officials gathered around my boat. It became clear that I would be protested and likely disqualified if I raced that boat in the finals. So I switched to another boat without the riblets for the finals. I finished 5th, just over 2 seconds behind Jeremy West, the winner of the 1000 meter event. If I had raced with the riblet boat, I likely would have won the final (although it would have been close) and then promptly been disqualified.

The ICF expressly banned riblet material shortly afterwards. However, I did win the 1000m World Championships the following year by an incredible margin of 3 seconds, paddling the newly designed Ted Van Dusen Eagle. 3M later mentioned in promotional material that they had supplied riblet material to the US Canoe & Kayak team. The East Germans immediately jumped on this, insisting that I must have used the material on my boat in the 1987 World Championships - feeling that was the only way I could have won by such a margin. The following year Norman Bellingham & I raced the same K-1's at a competition in Brandenburg, East Germany. When we crossed the finish line, the boat control tent was swarmed with German officials armed with stereo microscopes checking every square inch of our boats to see why we were paddling so fast. They found nothing, but it made for some good excitement!

So where does this leave you? The best advice I can give is that you want the surface of your kayak to be as smooth and clean as possible. While “magic” surface finishes are unlikely to increase your speed, a smooth surface WILL make you faster. The smoother, the better. You don't want any bumps, scratches, or dried on crud disrupting the flow of water over your hull. If your hull is rough or oxidized, start by wet sanding the surface. Use progressively finer and finer grit sandpaper, all the way down to 2000 grit if you can find it. While 600 grit is the finest you're likely to find in most hardware stores, auto body supply shops usually carry the ultra fine grits. Once you've sanded the surface perfectly smooth, use polishing or rubbing compound to make it even smoother. An orbital buffer with a nice soft pad will give you the best finish. Now you're ready to race.

Another question I often hear - rather than polishing to a mirror like finish, wouldn't it be better to end with 400 or 600 grit sandpaper, sanding lengthwise down the boat to create a riblet effect? My answer is NO. It is impossible to sand accurately enough to keep the sanding grooves perfectly straight and parallel down the entire length of your hull. The only way you could accomplish this would be to use a CNC machine or robot to do the final sanding. If you succeeded with a machine to sand that accurately and raced it in an ICF controlled event, the stereo microscopes in boat control would pick this up and disqualify you. It's far better to just make the surface as smooth as possible, without worrying about which way the sanding scratches are oriented.

Now you may ask “but what about wax, should I then put wax on my polished hull?” The answer is that it's a matter of personal preference - it probably won't make much difference! One reason it may help, is by keeping your hull cleaner. If you are the type of person that doesn't like to clean and dry your boat, then wax will keep it cleaner (allowing water scum and other grime to slid off more easily), resulting in a faster hull. If you keep your hull perfectly clean after polishing, by rinsing and drying after each practice session until race day (and keeping it out of the sun to avoid oxidation of the surface), then you're probably just as well not waxing it - in case I was wrong and the surface tension caused by wax really does impart 0.001% more drag!

By the way, all Epic Kayaks are polished with a high speed buffer before leaving the factory, so they are ready to go when you buy them. However, if your boat is older and you notice the finish is not as smooth or shiny after exposure to sun, saltwater and/or pond scum, then a good cleaning and polishing (with or without wax) will put some more speed back into your boat!

So go ahead and wax your boat if you are so inclined. It will keep your boat cleaner and help protect the surface from UV light (you can also products such as 303 Protectant that will preserve the finish of your boat). While the wax may not give a noticeable drag reduction compared to an otherwise clean, smooth hull, it just might give you a psychological boost knowing that you have the shiniest hull in the race!

epic_boat_surface_advice.txt · Last modified: 2020/09/16 21:49 (external edit)