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  canoe trim for racing ??
  Posted by: mrgreen on Feb-10-13 10:40 PM (EST)
   Category: unassigned 

I am planning to do a 28 mile race this summer on a very shallow and twisting river. paddlers are each about 180 lbs. We will be paddling a jensen 18 in fiberglass layup. what is the ideal trim for the most speed? bow light? bow heavy? and by how many inches? if any of you brilliant paddlers can help me i would appreciate it. thanks, MrGreen

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Messages in this Topic

 

  My wife and I race a 17 foot Jensen,
  Posted by: Jackl on Feb-11-13 5:44 AM (EST)
-- Last Updated: Feb-11-13 1:48 PM EST --

a comp cruiser, and an 18'6" Susquehanna and even though we are both a lot lighter then you, we always look for complete trim. A tad bow light is ok, but never bow heavy.
Unfortunately we are not "brilliant paddlers", so I might be all wet on the way we do it. No pun intended !

Jack L

 
 
  Perhaps for a twisting river, you might
  Posted by: g2d on Feb-11-13 3:43 PM (EST)
want to be just a smidge bow light. Canoes designed more for general purpose and less for speed may have more bow than stern rocker.

But one rarely seen boat, the 17 foot Bluewater Freedom, has more stern rocker, and is known for both decent cruising speed and for maneuverability on twisty channels, which it manages by its loose stern being able to swing wide a bit on turns. Not a full skid, just a controlled slide.
 
 
  Dead Level
  Posted by: plaidpaddler on Feb-11-13 5:12 PM (EST)
Dead level is my preference. A half bubble bow light is ok, but not bow down. The Jensens have no rocker and the 18' is not the best choice for a tight stream. Especially a glass hull with two full sized paddlers.
Practice heeling the canoe to the outside and try to stay in the deep water on the outside of the bends. Cutting across the shallow flats on the insides will put you into the suckwater and you will waste a lot of energy keeping up your speed. That will add up over 28 miles.
The Baldpaddler has a lot of experience in the 18 Jensen with a BIG partner on just the water you describe.
Bill
 
 
  Trim
  Posted by: mcimes on Feb-12-13 9:25 AM (EST)
As others have said you want to be perfectly trim or slightly bow up. Also, as others have said, being comfortable leaning near the edge will help you turn a lot. If you can, go out with your partner and get really comfortable near the edge of staying dry. Even take it so far you swamp it a couple times (in a few feet of water). Knowing the limit of your canoe is very helpful.

The Jensen 18 is a great boat and should treat you well. Its very predictable and stable as far as fast boats go, so if you know how far you can lean it will help on a small stream.
 
 
  trim
  Posted by: captainsmollett on Feb-13-13 9:53 PM (EST)
I trim my Jensen 18 1/2 inch or so bow down. At speed it runs a little bit bow up.

 
 
  Touche
  Posted by: MCImes on Feb-13-13 10:46 PM (EST)
You're right. If you can be that precise with your trim 1/2" bow down would be ideal so that at speed you're perfectly level.

Also below; its a good point that at no point do you lean your torso. thats a good way to get wet. It should be said that you "lean" from your hips, not body. Heel is a more correct term.
 
 
  Bow light...
  Posted by: openboater on Feb-14-13 7:06 AM (EST)
at speed the hull will plane out. Bow down and you plow.

Just sayin'
 
 
  displacement hulls do not plane
  Posted by: captainsmollett on Feb-14-13 9:46 PM (EST)
bow light just means that your stern is going to be sinking further into the water at speed,shortening your waterline and increasing resistance. Planing hulls have a wide flat stern to allow the boat to "ski" on the area that is in contact with the water. Once they reach a certain speed they will ride up ontoo that flat base, ride over the bow wave and plane. A displacement hulls speed is dependant on its length. They are designed to ride between the wake coming off the bow and stern. The longer the boat, the faster it can go since the distance between the two waves is greater. When you look at a racing canoe you notice they have a nearly vertical bow and stern. This is to maximize the waterline length when the boat is moving. Bow down always if you are looking for speed. The boat should be as close to level as you can get when you are moving at your cruising speed.
 
 
  OP is racing tandem in an 18' Jensen.
  Posted by: openboater on Feb-15-13 3:34 AM (EST)
If you set up bow heavy, the bow will plow deeper as the bow paddler drives forward with each stroke. Set up a little bow light to compensate.

Bow heavy will not help the situation either if you're climbing waves and trying to move up on other canoes. Bow paddler can adjust forward once the hull has climbed the wave and is now trying to surf out in front of it.
 
 
  Never level...
  Posted by: openboater on Feb-15-13 4:09 AM (EST)
When you watch a race live or on video, note the hulls are never level. Wind, chop, other boat wakes, and body movements of the racers all keep the hull bouncing. The best racers are usually the ones best and keeping the hull moving as smoothly as possible, but she'll never be flat. Good form goes a long way.

When trimming the canoe for race, one also has to consider other factors: upstream current, downstream current, open water, choppy or wavy conditions, paddler ability, etc. Each situation can benefit from different trim.
 
 
  The term is heel, not lean
  Posted by: kayamedic on Feb-13-13 10:22 PM (EST)
In this case semantics can be important. I told someone to lean the boat once. The person got "lean" and did not get "the boat". When they leaned over, they got very wet.

Heeling is tough sitting; you do have to keep your torso vertical..parallel to tree trunks.

Its far easier kneeling. However that's a long race for kneeling.

The boat tilts, you do not.
 
 
  slightly bow down
  Posted by: baldpaddler on Feb-14-13 8:50 PM (EST)
at rest for flat water. once you start pulling it will level out. In shallows slide forward cause it will squat at s
 
 
  The shallows...
  Posted by: openboater on Feb-15-13 3:47 AM (EST)
Coming forward to drive the bow down in the shallows is only affective if you are able to "pop" the hull. The canoe also sends a wave off the bottom of the hull, thus in the shallows, the wave hits the bottom of the river and bounces back up and "grabs" the hull. One of two things happen here. One, you either time your sprint into the shallows so as to "pop" or get ahead of your own bottom wave and surf it through the shallows (awesome feeling when it happens). Two, you get stuck behind your own bottom wave and have to climb it all the way through the shallows (suckwater). Bow down is not going to help the racers in this situation. Suckwater is the term used to describe the hull being held back by it's own bottom wave in shallows.
 
 
  No wonder we beat you all the time!
  Posted by: jackl on Feb-15-13 7:10 PM (EST)
You need to stop that plowing and get the bow a tad up, or at least trim

Jack L
 
 
  Notice JackL
  Posted by: baldpaddler on Feb-17-13 6:23 PM (EST)
You started beating us when we had to switch seats due to our bow paddler putting us several Inches bow down. If we could trim off 100 lbs combined we would start beating you again on flat water( we never will
beat you on the rivers...your bow is too pretty and skilled)
 
 
  I heard that you have a cute new ......
  Posted by: jackl on Feb-18-13 5:19 AM (EST)
little bow paddler, that should be groomed in about ten years.
Congrats on your new and first grand daughter!

Jack L
 
 
  Confusing. Has the OP been answered?
  Posted by: Glenn_MacGrady on Feb-15-13 1:05 PM (EST)
The OP specifically asks about maximal speed in an 18' Jensen in a very shallow and TWISTING river.

I don't paddle in racing hulls, or fast in any boats, so I don't really have any opinion or experience to offer. However, the answers seem to be contradictory so far: level trim, slightly bow up, slightly bow down.

The bow down advice seems to be premised on the bow "rising" at speed. I have two questions about this premise. First, suppose you can't get up to the requisite speed on a very twisty river or stream. Then what's the best trim? Cruisers will often shift weight forward to increase ease of stern skid turning, but I think this bow down trim probably slows overall velocity.

Second, in what respect does the down trimmed bow "rise" at some certain velocity? Does the bow freeboard actually increase from the gunwale line to the water line - thereby equalizing freeboard trim along the hull? Or is this rise simply the entire bow section of the hull being lifted vertically by the bow wave, with the bow freeboard remaining in the same trim down position with respect to the waterline? If it's the latter case, then a bow down (plowing) freeboard would still seem to be in a bow down plow even if the entire hull angles upward on the bow wave.

Again, I don't paddle fast enough, or tandem, to notice these effects. My unbrilliant, non-racing and simplistic view is that a properly designed hull for speed is designed to run at level trim. Otherwise, presumably, the designer would have designed in a different resting trim.

I do notice slowing in shallow water, but never thought to trim forward in my solo canoes to alleviate this. Not sure I understand what "popping" is from the descriptions so far or how it relates to trim. Can you "pop" at level or bow up trim?

 
 
  I trim bow down
  Posted by: captainsmollett on Feb-15-13 11:02 PM (EST)
thats how racers run their canoes. When you catch up to me at the finish I will be happy to explain hydrodynamics to you












 
 
  I believe you
  Posted by: Glenn_MacGrady on Feb-16-13 1:29 AM (EST)
And I read on racing forums that other marathon racers similarly believe in a slightly bow down resting trim. However, I see at least a minority of marathon racers on those same forums who prefer neutral resting trim, or who believe it depends on the hull shape of the particular racing canoe.

As Openboater points out, it may also be relevant whether you are paddling upstream, downstream, upwind and/or downwind as to what trim is most efficient. And again, the OP asked specifically about twisty rivers where there is not the same top speed potential as on open water.

Olympic sprint canoeists go faster than marathon racers and do everything possible with equipment and technique to win by millimeters. Below is a video of the 2011 world championship 1000 meter race.

Are these canoes bow down at rest? Are they in neutral trim at speed? I frankly don't know and can't tell. The bobbing of the entire hull caused by the solo paddlers' weight shifts and stroke movements completely mask to my eye any hydrodynamic bow lift. If anything, I think I see the sterns get closer to burying during the bobs than the bows do.

In any event, I think this thread is the ideal venue to discuss and explain the hydrodynamics of bow lift and trim, not at the end of some hypothetical race.

http://www.youtube.com/watch?v=C1fIE-PwvQs
 
 
  Jensen 18 trim
  Posted by: canoeracer on Feb-16-13 7:10 AM (EST)
The jensen 18 is an old design. If racing this canoe in shallow water trim it atleast 2" bow down when the canoe is not moving. When moving the bow will rise up. A very strong team would run it more bow down. It will be easier to turn is it is not stern heavy. This canoe has little rocker by running it bow down it will free the stern for easier steering. I have been racing canoes for 45 years.

Bruce Barton
 
 
  What Bruce says...
  Posted by: openboater on Feb-16-13 8:28 AM (EST)
-- Last Updated: Feb-16-13 8:30 AM EST --

...goes. I bow to thee.

It would be tough to dispute what Bruce says about anything canoe racing! But it's fun to have the debate. I've had good success myself canoe racing when I was/am able to train. Love this stuff!

And to Captainsmollett, I hope some day we can do a little sidewaking and such.

Openboater

 
 
  Thanks Bruce
  Posted by: mrgreen on Feb-17-13 12:04 AM (EST)
it sounds like you are the man to believe. I was getting a little confused there for a while. I will try it out when the water gets softer and let you know how it goes.
thanks, Mrgreen
 
 
  A lot depends on the team
  Posted by: baldpaddler on Feb-18-13 8:58 PM (EST)
When Randy and I were slim and fit we could kick a** in our class running slightly bow down(at rest) Now we just want to get to the end with out swimming..With a weak team(or partner) I try to start out level or bowlight.
 

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