Avoid the squat: how to trim your boat.
Assuming the former, let's talk "TRIM"! A boat's stern will sink deeper in the water as more power is applied. Basic physics applies here as the hull is put under more power, the bow will rise and the stern will, well,…."squat" (a highly technical term, used only in the most hallowed-halls of kayaking think-tanks across the globe). We want to avoid a "squatting stern", as this creates unwanted drag. Drag, of course, cuts into our efficiency, and heaven-forbid we lose one fraction of that!
I think it's important for every paddler to understand that boat designers, (of which I am), are forced to place the seat of their crafts in a spot that GENERALLY will provide the least amount of "stern squat" and the best overall boat trim to an "Assumed Payload". Ever since my first days of racing, (1982), I have been taught to adjust my seat to a spot that is best for MY PERSONAL weight and speed. Ever since I've entered the world of "boat design" , I've become keenly aware that many boats out there should be "dialed-in" related to trim by their new owners. The variables are too great for any boat designer or manufacturer to "nail" the exact spot for the seat, right off the shelf. The computer calculates the center of the boat and they do all the math that they can do in order to place the seat in it's appropriate spot. However the best placement is really an individual thing. The shape and weight of one paddler's body can vary greatly from the next, (which is a beautiful thing!), and these differences can affect boat trim.
Every time I get a new race boat I check the trim and adjust it accordingly. It makes no difference to me whether it's a Phantom Surf-ski or a Prijon 89 Wildwater boat. I guess I don't pay that much attention to my river play boats, as straight-line speed is not a requirement. However, when I get my New Perception Avatar touring boat, I'll check the trim on this "recreational toy" too also. Efficiency folks, not only in your stroke technique, but also in your equipment!
Here's how I "trim my boat":
* Find a flat "true" surface - A large table, a smooth absolutely flat piece of concrete, a steel I-Beam… you get the idea.
* Place your boat on this surface.
* Take a tape measure and a waterproof magic marker
* Go to the Bow and measure off the flat surface, making marks every 1/2 inch from the surface up the bow. Place a large number representing the one-inch, (or centimeters) increments off the surface next to each mark where appropriate. Leave the 1/2 inch marks unnumbered if you wish, but make them large enough to see from shore.
* Go to the Stern and do exactly the same thing. Depending on the rocker of the boat, some numbers will not be available, just measure up until you get to the first one that corresponds to Bow measurements and then mark upward from there.
* Go to the water, and take a friend. You need to find a dead-flat piece of water where your friend can clearly see the boat markings from either the shore or the water. The shore seems to work best.
* Do sprints back and forth in front of your buddy to see how the numbers in the Bow match up to the numbers on the Stern when the boat is UNDER RACE-PACE POWER. You must get your boat to hullspeed to perform this test. If you are checking the trim on your Touring boat, do the same thing but simply paddle at normal "Touring-Pace" vs. Race-Pace.
* If the Stern is "squatting" when the boat is under the proper amount of power, you need to "scootch" (yet another highly technical term), your seat forward a bit. If the Bow is sinking deeper than the stern, the seat needs to move backward a bit. One inch can make a difference, so do this a little bit at a time.
* Repeat the drill (you really need to TRUST your friend's judgement!) until the numbers at the Bow, match those at the stern.
* Take the waterproof marker and make marks on the inside of the hull where the proper seat placement should be once your pal gives you the "thumbs-up". Go home and readjust the placement as required.
Please note that this is the method I was taught "many moons ago". If there is a Hydro-Physicist, Olympic Coach or a Marine Architect out there somewhere that begs to differ, lets hear about it! If there are more scientific methods to go about trimming a kayak, our readers would love to hear about them. The bottom-line is, that a paddler should not automatically assume his or hers seat is EXACTLY in the correct spot just because it came out of the box that way. Check it out for yourself, cuz after-all, "nobody wants "squat"!
My dearest "Don't Know Squat", I suggest you change your name now, as after reading this, you will certainly know more "squat" than before! Perhaps "Super-Squat" or "I Da-Squat" would fit better from here on out….
Cheers, Brent Reitz