Secret Rowing Weapon #4: How to trim your shell’s hull
June 28, 2010 by
Filed under Hull
The last post focused on determining if you might have a problem with the trim of your shell’s hull. Here are a few solutions to try if you do have a problem.
A hull that is not properly trimmed is neither as effective nor as efficient as it could be. In essence, energy is being wasted.
Here are four solutions that you can use to trim your hull. Generally speaking, if the boat is out-of-trim it is better to have a hull slightly bow-heavy rather than stern-heavy. The key word there is slightly.
Not everyone will agree with this, but a stern-heavy boat is similar to a coach launch at half speed. It makes a bigger wake as it pushes through the water—and that means the rowers are paying a price.
Secret Rowing Weapon #3: Is your hull trimmed?
(This post is cowritten with Casey Baker, from Resolute Racing Shells.)
The trim of a shell is an interesting measurement. Interesting mainly because few rowers pay attention to it. Really interesting because it is a place where you can pick up some quick speed with very little effort.
The trim is how level the boat is when it is sitting in the water. The goal of properly trimmed shell is to have the boat as close to level as possible throughout the entire stroke cycle. All things equal, a properly trimmed boat will be faster than a shell that is not trimmed.
When people are added to a shell the trim will change. And with moving seats, and moving mass, the trim of your boat will even change during the stroke. And significant differences can slow you down.
Many rowers and coaches have placed little if any focus on a shell’s trim. And because of this the trim could be a secret weapon for you.
To utilize your new secret weapon, you should first determine if your hull’s trim is where you need it. Try these two methods to determine if your trim is right for you.
Method #1: Quick Method
Put your boat in the water. Then put your rowers in. Take a 3-foot-long level and put it on the gunwale. Have the rowers come to the catch. Then have the rowers come to the finish, and then sit at the mid drive. Notice the reading of the level in all three positions.
How were the readings?
At the mid drive, was the level centered? At the catch was there a slight stern drop? At the finish, a slight bow drop? If any of those readings were off more than just slightly you might have an issue.
If from this quick test, you think you have a problem, then you should probably adjust your trim (and I’ll discuss that in the next post). If you want more specific information about how severe your trim-issue might be, try this . . .
Method #2: Advanced Method
Get some pinstriping tape, black in the case of a white boat, about 1/8” thick, and make three hash marks with the tape on the bow and stern of the boat just like you would see on a ship. This tape is wrapped around the bow, as well as the stern to show on both sides of the boat.
Make the top and bottom pinstripe 1cm above and below the middle stripe. Also make the middle stripe the longest, like 2” on each side and the upper and lower stripe shorter, like 1 ½ inches. You can set the marks from an empty boat in dead flat water, or with a crew loaded in the boat. The goal is to have the marks give you your indication of trim both bow and stern.
Now put your team in the boat, and have them row. What are you noticing on the trim markers? Significant drop to bow or stern? These markers will not only give you an idea of whether you have a problem, but how significant the issue might be.
In the next post I’ll go over two of the more popular ways to trim the hull in your shell.
Until then, let us know of any thoughts you have. Just leave a comment below.
Preparing Your Rowing Hull for Fall Season
August 3, 2009 by
Filed under Hull, Keeping Your Stuff Alive
Here is an interesting question from Travis:
Hey Mike,
So we’re gearing up for the start of Fall season already down here in Florida. We are about to do some work on our hulls and had a questions for you. How best to prepare the hull: 1) Clay bar the hull and then wax it, or 2) Use rubbing compound on the hull and then polish it? Our boats were stored outside for a few years while our boathouse was being built and now that we have a home we want to make our boats look great again…any help would be greatly appreciated.
Thanks for the question Travis. It is one that I do get quite often, and have several posts on it:
. . . but it is certainly a question worth discussing some more.
Cleaning the hull of the men's 8 at 1996 Olympics
The hull of a shell is one of the most critical, yet overlooked, parts of a boat. It’s function is just not speed but also rigidity. When there is a hull problem, especially a problem under the waterline, there is an entire boat problem.
One of the best methods to prevent hull issues is maintenance . . . smart maintenance. This begins with keeping your hull clean. I won’t go great detail here, since they are covered in the other posts listed above, and the Special Report, Last Almost Forever. But the critical theme is to keep it clean, and then to protect it, especially if it is stored outside.
I would suggest, in your case, not to go with Clay Bar. Although I have never used the product (and if anyone has please comment below) but researching it left me with the impression that it would leave a residue on the hull that you would not want, and the focus would not be on really getting the hull clean. And clean is critical when racing.
I’m going to suggest that you use rubbing compound, with a grit (the measure of abrasion) between 1500 and 2000. Here is a product very similar to what I use, 3M Rubbing Compound, 16oz (3M 39002)
Careful as you work the compound. You are just trying to remove grime or oxidation and not scratch the hull.
After cleaning the compound off I would suggest to coat the hull with a very thin layer of nice car/boat wax. Make sure that the wax has UV protection in it. It should say that on the label.
As you get close to racing, then remove the wax, because it will slow the boat due to friction.
I hope that helps, and if anyone has suggestions for Travis, let us know.
