Question for the engineers

I have been reading the post on seat placement on the QCC models and other kayaks.

Why doesn’t anyone develop a slide bar for the seats like they do in cars.

sliding seats are available already

– Last Updated: Mar-22-07 7:50 AM EST –

in competition kayaks and the like,
and Mariner kayaks has them in their touring kayaks.
Why they aren't available in more touring kayaks,
eludes me.

could be a nice feature but…
I’ve had to move a few seats around and found it could screw up the tunnel placement of your spray skirt since they are built with the center point of the body in mind. A well designed kayak has a “swing” point that makes turning and tracking easier and you’d be amazed at how moving a seat around both back and forth or by raising and lowering can affect a kayak. So the manufactures pick the sweet spot and if you have special needs most (but not all) seating is easy enough to move a few inches if you are willing to do a wee bit of retro-fitting. I know this will sound stupid but hear me out. I’ve seen beginners at demos jump into a kayak and hop right out proclaiming “I don’t like the fit on this…my knees were jammed up against the deck and the seat back hit me wrong” Of course they didn’t realize the previous paddler had moved things around to suit them. Can you imagine if the seats were on tracks how many paddlers could possibly assume a boat weathercocks like mad or other such maladies if the seat is out of the sweet zone when they demo? So I’ll guess the manufacturers are mindful of providing track seating being a double edged sword even though it does have real merits.

Sliding hardware
My flatwater boat has a wooden rail system to allow seat movement over about 10" of travel. It isn’t an easy adjustment to make - takes fiddling, with your head inside the boat to see what’s happening. But the setup itself is fairly light. Since I initially adjusted the trim of the boat, I haven’t moved it.

I think the major drawback to an easily sliding seat, i.e. something you could adjust while sitting in it on the water, is weight. All the paddling, bracing, etc. forces that you exert are communicated to the boat through your butt, knees and feet. Knees push up, feet push forward - easy to deal with. But your butt pushes the boat in all directions while paddling, so the mounting needs to be robust. A car seat also deals with multi-directional lateral forces due to starting, stopping and turning, and the seat sliding mechanism is correspondingly heavy duty. One could design a lightweight aluminum rail system for a boat, but it would be pretty expensive, I think. Would it be worth it? Once your seat is in the right place, would you really want to move it around much? My guess is it wouldn’t pay off in the long run.

a sliding seat could replace

– Last Updated: Mar-22-07 2:04 PM EST –

(the function of) a skeg.
Sounds ideal to me.

Virtually all WW kayak seats are
adjustable, but every time I have gone to make an adjustment, it has taken massive effort to get the screws and the seat loose. Recently, some manufacturers have been trying to improve the situation.

One reason for the relatively primitive seat adjustment is the need or desire to get hull support from the seat pillars. If the seat is on tracks on the boat floor, some other means must be provided to support the hull.

Today I need to move the seat back a little in my Necky touring kayak, and I’m already dreading the struggle. The mounting looks exactly like that in my WW boats.

… move whole paddler and seat to alter trim to balance for weather, and alter paddlers relation to their outfitting in the process ---- or outfit for paddler and just move a small blade up and down for adjust for weather…

I get the sliding seat for racers - with minimal outfitting/knees up position - for minor trim/fit adjustments, but not weather helm (they have rudder for that).

“a sliding seat could replace

Posted by: Dirk_Barends on Mar-22-07 2:04 PM (EST)

– Last Updated: Mar-22-07 2:04 PM EST –

(the function of) a skeg.

Sounds ideal to me.”

Seat position can not replace a skeg.

Kayak skegs are adjustable. By varying the amount of skeg “in the water”, you can render a decently trimmed boat neutral in most conditions by considering & compensating for three variables: the ‘center of gravity’, the ‘center of effort’, & the ‘center of lateral resistance’.

You cannot acomplish all this by changing seat position because that has little effect on the ‘center of lateral resistance’.

Educate yourself on matters of boating & the Sea before making a statement such as this.

There’s a way to post your comment
closer to the post on which you are commenting.

Increases seat height!

– Last Updated: Mar-23-07 12:52 AM EST –

Slider mechanisms would not only increase mass, but by necessity also raise the seat height, thus raising the CG.

my sliding seat just works
the same way as I would use a skeg to overcome the effect of weatherhelm.

Sliding seats
>Seat position can not replace a skeg.

Kayak skegs are adjustable. By varying the >amount of skeg “in the water”, you can render a >decently trimmed boat neutral in most >conditions by considering & compensating for >three variables: the ‘center of gravity’, >the ‘center of effort’, & the ‘center of >lateral resistance’.

You cannot acomplish all this by changing seat >position because that has little effect on >the ‘center of lateral resistance’.

Educate yourself on matters of boating & the >Sea before making a statement


Here’s a quote from a couple of people that are pretty educated on matters of boating & the Sea:

“The greatest advantage of the sliding seat is in fine tuning the center of windage and the hull’s center of lateral resistance to being blown leeward. Properly balancing these forces allows for easy tracking at any angle to the wind without dragging a rudder along at an angle”.

The above quote comes from the Mariner web site (

(I’m leaving town and won’t be able to respond to questions/remarks and/or insults to my family lineage etc., for a few days :-).


Re: opinions
In response to the semi-slam to the Dutch p-netter above, the website of the person being slammed has a pretty impressive list of publications on canoe technique which he seems to be too modest to mention. If he has an opinion that a sliding seat can replace the functions of a skeg, isn’t that his right to express it? Particularly in this forum which is designed for discussion.

The fact that the Broze brothers share his opinion to a certain extent counts for a lot. Clearly the response of a hull to a shift in the paddlers position will vary based on the details of the hull shape - i.e. what is pushed lower in the water and what is lifted out of the water due to a shift in CG. Mariner boats look to have strong fore/aft asymmetry, so a change in trim could indeed affect both tracking and weatherhelm - plus drag, stability, etc. etc. How much of an effect is another issue entirely and subject to the usual testing (OK that almost never happens) and subjective debate which is what we’re doing right now.

I say the more opinions the better - I can sort out the ones I think are nonsense for myself.

indeed an opinion
based on my own experience and what I have read, I thought I was pretty conservative by saying that it sounds like an ideal solution to me. If it really is, that is indeed what we can argue about here, and – hopefully – get to to know more about it. So far, most of the comments and insights are interesting.

Spray Skirt
I use a pretty tight-fitting neoprene spray skirt. I can’t imagine being able to slide my seat too far in either direction because it wouldn’t fit anymore. Just a thought…

If Not A Slide…

– Last Updated: Mar-25-07 6:12 AM EST –

at least a few different positions for the customer to fairly easily choose from.

Forward / Center / Back

A few bolt holes here and a little less flare there would make a big difference.

I can make lots of adjustments to my bike saddle without becoming a foam cutter. Why not the kayak?