Wednesday, November 23, 2005

surfski paddling in rough water

Here in Vancouver we often get short period (2-5 seconds), 0.3-1 m amplitude waves as a result of high winds and short fetch. The Jericho PNW-ORCA race of 2005 was a good example. The resulting waves rarely travel faster than 12-15 km/hr. At under 13 km/hr (~8 m/hr) the waves are often slowing me down, acting like speed bumps requiring lots or rudder work to hit the shoulders or low spots consistently. To build good surfing speed in these waves, I have found that quartering the waves (surf them at 45º or more from the direction of the wave front) is most effective, which often sends me off in a direction other than where I want to go, meaning I have to tack a great deal to maintain a productive heading in a race or training.

Going into these waves is another story. Aside from the wind, the impact on the hull is quite significant. I would advise anyone paddling in very steep waves, even of only 2-3 feet in overall trough to crest height to carefully inspect their hull after paddling. My Mako Millennium (vacuum bagged carbon) ended up needing the seams on both sides under the cockpit reinforced as both blew out in 4-5 foot sections (about 6 months apart). I suspect that the water conditions aggravated a weakness in this area with all the seesawing and subsequent impact. On numerous occasions I have had my ski ½ airborne with the front half, including me at times, out of the water. The impact on landing is hard to lessen (by leaning back as you teeter over the top). And for those who caught the body rocking reference, going up steep waves lean forward slightly, then back slightly on the descent, only by 5-10º at most. All the lean should originate from the hips, not the lower back.

So be careful, as blown seams in big water means sinking as most skis have no internal positive buoyancy chambers.

Alan Carlsson
Engineered Athlete Services

1 comment:

Tunder said...

You have a great blog site! Love it! I am currently in the market for a boat. Friend of mine just got a Mako 6 with a fiberglass lay-up. I was thinking about getting the same boat with a composite lay-up but now am just a little worried about the structural integrity. Is the fiberglass going to be stronger?