Re: [Paddlewise] Sliding Seat Failure

Matt;

Firstly,

Here is the part of your long recent post which I found most interesting:

"We have an eyelet inside most of our kayaks (those that don't have a rear
bulkhead) that a cord could be tied to limit forward seat travel or help
contain
 any gear that might be in danger of shifting."

Why didn't you say so? You have done what I have been talking about. Where
is the eyelet positioned? Would it be worthwhile to consider fitting more
than one eyelet?

Do you fit eyelets to restrain the bow float/gear bag?



Secondly,

Some comments on the rest of your post:



It would be better to talk about this subject when the real-world failure
example mentioned by Steve Scherrer is better detailed, but the outline is
enough to make some comments.

 "Peter, during the Boat Trim discussion and here you seem to have a way of
 not understanding what I write and them making assumptions that aren't
correct about it.  Are you perhaps, a lawyer, or do you practice this
technique for some other purpose?"
Matt, I might say the same about you in several responses, but this sort of
exchange, that is shooting the messenger instead of dealing with the
substance of the message is not interesting or productive. You may think you
state your ideas clearly, but like all of us, what you post often leaves
room for further clarification. BTW, I have sent
a brief bio to Pete Osman, you should do the same. That answers some
background questions.

 "Surf that most kayakers would choose to come in or out through is not
extreme conditions in my mind just like it is apparently not in yours."
The conditions that would produce the most risk of the sliding seat moving
would be the steepest waves, surf, with the bow or stern spearing into the
water and hitting something? Isn't there some risk of getting into these
conditions for a lot of paddlers? Shouldn't the sliding seat arrangement
cope with this?

A paddler may not intend to get into these conditions, but if he or she
does, the boat should not be the problem. Let's say a paddler goes out on a
day with 1 to 2 metre swell predicted. As the Oz weather forecasts always
say, waves can be up to twice the predicted significant wave height. So the
paddler ends up coming in through higher than expected surf, and
pitchpoling. I'm sure you've seen boats standing up steeply on their noses
in pretty small surf, when they align just right, when the wave is at its
steepest.

"To me that sure sounds like a lawyer writing."
If you get into lawyer bashing, I'll start posting engineer jokes! "Three
years ago when I started this course, I couldn't even spell engineer, now I
are one!"

"...then you ask "why should the unwary purchaser". I ask you, how did the
purchaser get back to being "unwary" we certainly haven't been trying to
keep him in the dark, we put the warning in bold faced type even though it
might not have been
necessary to do so at all as we had no examples to go by only our own
concern about the possibility."
I'll give you full credit for imagining the possibility of sliding seat
entrapment, and warning about it in your manuals, even if you had never
known of an experience to warrant it. While we are talking about your
manuals, I'll give full credit for them generally. Your website manuals are
among the best resources for sea kayakers around. But why don't you go the
easy next step, and provide sliding seat restrainers as part of the boat
set-up when it is delivered to the customer? It would seem to be a
straightforward step to take. Likewise, how hard or expensive would it be to
provide tie-down points to prevent gear bags or float bags from moving in
the boat? The risk of sliding seat entrapment might be low, but if it
happens, the consequences may be very serious. Any prudent paddler owning a
sliding seat arrangement would be better off making sure the seat has a
limited range of movement, and cannot shift forward and cause difficulty in
wet-exiting. Why wait on the off chance of "extreme" conditions?

"Spearing the bottom in our kayaks is practically impossible to do, even in
extreme surf, because they all have a full volume bow with raked or rounded
high ends (and surf is one of the reasons that they all have these shapes)."
I think we established in previous exchanges that the Nadgee Expedition and
the Mariner Max have similar hull shapes. Read here about a Nadgee
Expedition spearing the bottom and breaking off 1.5 metres of bow:
http://www.nswseakayaker.asn.au/magazine/46/m-and-m.htm
So it is not practically impossible, it is a real possibility and has
happened.

"Of course, anything we might do to fix the seat may create the potential
for some other hazard as yet unrealized."
Oh come on, deal with the known and foreseeable hazards. Why recommend the
sliding seat restraint to paddlers who are going into "extreme" conditions,
when you think there might be unknown hazards? Round the loop mate.

"Should I expose the 99% of our customers to those as yet unknown hazards
due to changing a system that has not caused anyone problems we knew of
before?"
Yes, if there are no foreseeable hazards with the fix, and you cure a known
problem.

"In all my time playing in 6+ foot surf I've never had the seat move more
 than the slightest bit either forwards or backwards from the position I
 started out in..."
So is Steve Scherrer's instance the only known sliding seat failure?

"If the kayak is heavily loaded there is not much room for the seat to slide
 forward at all ..."
Most trips are lightly loaded day trips, except for the lucky. Again,
putting some padeyes or similar there to restrain the load is such a simple
matter I still can't see why you would not do it.


" Peter's suggestion of adding a front bulkhead could only prevent
especially long-legged paddlers from moving too far forward."

Measure this. Are we talking Michael Jordan against a pygmy? In a less
extreme range, a bulkhead positioned for a long legged paddler will stop a
short legged paddler pretty soon, and soon enough, certainly before the
paddler is up to his or her armpits.



"A large float bag (like we sell to fit our kayaks) could be inflated fully
and placed so that it came back to near that particular paddler's foot
pedals to limit the possible
 slide range forward for any leg length person (as could gear bags, but not
 fixed bulkheads unless they were custom installed for a particular
paddler)."

Sure you could position a float bag or gear bag to limit forward travel. At
least you seem to agree that the seat should be limited in its forward
travel, and we are now just talking about the best method. Why not restrain
the seat from behind as an alternative, or as well? A bulkhead is as valid a
method as movable floatation.

"We do custom install front bulkheads sometimes in the Mariner II but that
 will tend to limit the potential market for that kayak (when it is resold)
 to people with shorter legs and/or smaller feet than the original
 customer."
Or the same size. Or, the bulkhead could be fitted to a larger person than
the purchaser if he or she is concerned about selling the boat later. Do you
really have people come in and say: "Matt, I won't even think about a front
bulkhead, that would limit the resale potential of my boat."? Why are front
bulkheads only offered in the Mariner II, and not the rest of the range?

"We will happily set up a sliding seat limiter (as described in the manual
or one
of the customer's choice if it seems reasonable to us) for anyone who
requests
 it (at no extra charge)."
Great. If you'll do this at no extra charge, that means the cost is fairly
small. So you could consider it as a standard part of fitting a sliding
seat, rather than an optional extra.


"[*Note I began to use a sea sock in surf not to fix the seat from
 sliding, but so I could stay out longer before having to come in and empty
 out the kayak again and to make the kayak lighter and less likely to be
 damaged--or damage me or someone else--if it was to come back to shore
full of water without me and possible wrap around a boulder or spear the
bottom
 in a shorebreak and fold due to the extra water weight]."
Seems like you have never seriously experimented with pumps. Try
out a boat fitted with a good foot or electric pump sometime. For my part, I
am still getting around to making a sea sock and trying it out.

 "The lawyers told us (manufacturers, retailers, renters,and guides) that
anything we said and (especially) wrote in the way of guidance for the
customer might well be used against us in court and advised us against
saying or writing anything in the way of safety information or "safe"
locations to paddle (or even limiting where the renter could take the rented
kayak at all due to safety reasons--because then it could be
 construed that the renter had approved all other locations as being
perfectly safe). Ludicrous, yes, but that was the reality of the legal
system at least in the US."
Ask a competent litigation attorney his or her opinion about selling a
product for a hazardous pursuit, and giving no advice as to its use, or
leaving important safety fit-out decisions to the purchaser. The advice you
get from a lawyer depends on the instructions you give.

"So far, I'm glad we made that choice [to write manuals and advise]."
Likewise, I don't like people deciding not to do sensible things because of
litigation paranoia.



"I think Australia, having such an abundance of surf, should pass a law that
each end of any kayak made from now on should have a large clown nose
ball-shaped bow and stern so if that kayak is used in the surf then it would
be less of a danger to the
 paddler, swimmers, surfacing skin divers, and near surface wildlife in the
 area."

Huh? Are you trying to say that a sliding seat restraint should not be used
because of the fantastic exaggerations you imagine here?

In creating this absurd drivel, you have touched upon one grain of truth. I
don't think kayaks should have very sharp edges and spear-sharp bows and
sterns, such as some stitch-and-glue boats do have. The BCU surfing rules
require a minimum radius on boats used in surfing competitions, as follows:
"Pointed Ends:All kayaks must have a minimum diameter of 50 mm (allowing for
6 mm protuberance) in the plan view. All kayaks must have a minimum diameter
of 20 mm (allowing for 6 mm protuberance) when viewed in the side view.
Kayaks may only be brought back up to the required radii by means of a
permanent repair or by the addition of a purpose made endcap. If the ends
are damaged during a competition, adhesive tape may be used to effect a
repair for the remainder of that competition."



"No holes need to go through to the outside of the kayak."

Good.



"I don't think a bulkhead would be the best attachment point for a seat
slide
limiter because the bulkhead would likely have to be made overly beefy."

The bulkhead shape could contribute to the necessary strength. I was
imagining a low profile padeye glassed into the hull at each side to attach
a cord or strap as a restraint method. If the padeye was fitted on the
bulkhead, it would be close to the hull or deck, not towards the centre of
the bulkhead.



"I don't want to create a greater risk for every new owner by attempting to
fix what is possibly only an imagined risk for a very small percentage of
owners."

What risk? I can only imagine one, that is foot entrapment in the cord used
to restrain the forward float bag or gear bag. That could be minimised by
placing the padeye(s) or eyelets carefully. That risk is balanced against
the risk of the floatation moving out of place, or escaping.

"The "literally up to his armpits" part did arouse my suspicions that the
report might not be entirely true (or was perhaps remembered incorrectly)
because that is just not what would happen if the seat were to slide well
forward (because the foot pedals are
 attached to the seat and move with it--so the paddler would remain in the
 upright seated position as they slid forward)."

Yes it would be good to get the story as accurately as possible, but couldn'
t the paddler's feet come off the footpegs, and slide under or around the
floatation in the bow, leaving the paddler to slide forward, and if not
"literally up to his armpits", then at least so far forward as to make an
exit very difficult? Remember if this happened, the seat has moved forward
to impede the paddler's body moving back and out.



" Why am I being so skeptical?. hard chines . longer cockpits. a rudder"

No problem with searching out the full story and trying to get it as
accurate as possible. And you might respect a bit of scepticism about
Mariner kayaks and your chosen solutions to the challenges of sea kayaking.
There are other valid choices.



 "What other kayak company spells out possible risks involved with kayaking
 like this?"

None that I know of, but here are some commercial sea kayaking sites which
set out good material:

http://www.atlantickayaktours.com/

http://www.useakayak.org/



"Lawyer types and sharp competitors may well attempt to use our concern
about our customers (and sea kayakers in general) against us."

Well, I'm not doing that, I'm saying that in a boat without bulkheads, I
think the floatation should be secured, not just jammed in. And if a simple
seat restraint can be fitted to a sliding seat, do it.

Cheers, PT
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