Single vs. Double Action Seats
Joseph Jacob
Could someone explain the advantages (or disadvantages) of single action seats
vs. the conventional double action seats?
--
Joe Jacob
(This is what I think, not necessarily what Aetna thinks ...)
Carl Douglas
In article <34198C...@RemoveThis.aetna.com>, Joseph Jacob
<Jac...@RemoveThis.aetna.com> writes
>
>Could someone explain the advantages (or disadvantages) of single action seats
>vs. the conventional double action seats?
>
>
Why we favour (well-made) Single-action seats:-
1. S/A run very smoothly and do not jam (jams occur when wear-induced
slack in D/A u/carriage lets axles slew, always at the worst moment).
2. S/A weigh less than D/A (can save up to 400 grammes/14 oz per seat),
due to simpler construction & because u/carriage braces seat top better.
(A quick way to cut excess boat weight).
3. S/A is usually a lower structure than D/A - enhances boat stability
by lowering C of G.
4. On good (stainless, correctly-greased & sealed) integral-bearing
wheel assemblies, S/A seats generally take several years in typical club
use on non-saline waters before bearings get crunchy. Wheels are then
easily replaced at modest cost. Salt water use may reduce bearing life.
(With bad bearings, & there are plenty around, life will be short in any
water. Yet the cost difference between good & bad is minimal).
5. S/A seats are normally far harder to dislodge than D/A - left in the
boat they stay in the boat.
But you do still have to pull that oar
--
Carl
from Carl Douglas Racing Shells
URL http://www.rowing-cdrs.demon.co.uk
GSpiess
Single action seats use a stationary axle whereby the outer rim of the
wheel turns on ball bearings. The best wheels have sealed bearings, as
opposed to those held in by a sprocket pin, which can pop out under
stress, as well as allow dirt to enter the bearing track and eventually
bind or fail. With double action seats, the wheels are affixed to the axle
so that the entire mechanism rotates as one unit. In order to limit
friction and increase the range that the seat may slide on the tracks, the
axles are mounted in slots on the seat carriage, through which they travel
while the seat is in motion. Thus the double action is the rotation of the
axle combined with the travel of the axle through the slot. The advantage
of the single action seat is that it has fewer parts to wear out, plus they
usually weigh less than the older design double action. Double action seats
were considered an innovation years ago to address the limited range one
could achieve in a boat that did not have adjustable tracks. Single action
seats, which came en vogue with more precise machining and ball bearing
technology, plus the advent of adjustable tracks, addressed the problem in
a more "elegant" fashion. Double action, however, remain popular with many
rowers, novice and elite, because of their lower cost, because not all
boats have adjustable tracks, and because they just have a certain feel and
traditional appearance.
George
Jimrows
My single-action roller bearings blew out after only 200 or so miles in my
Vespoli 2x. I replaced them at $80 for all 8 (they only come with the
wheels) and again they're starting to get loose. Soon I'll call the staff
at their shop and complain. This is ridiculous. I want D/A again. Less is
better. Outside of this, I love our boat and am happy with Vespoli's service.
Jim Cooper - Norwalk River Rowing Club - Norwalk, CT USA
Jim Dwyer
Carl Douglas (row...@rowing-cdrs.demon.co.uk) writes:
> In article <34198C...@RemoveThis.aetna.com>, Joseph Jacob
> <Jac...@RemoveThis.aetna.com> writes
>>
>>Could someone explain the advantages (or disadvantages) of single action seats
>>vs. the conventional double action seats?
>>
>>
> Why we favour (well-made) Single-action seats:-
> 1. S/A run very smoothly and do not jam (jams occur when wear-induced
> slack in D/A u/carriage lets axles slew, always at the worst moment).
> 2. S/A weigh less than D/A (can save up to 400 grammes/14 oz per seat),
> due to simpler construction & because u/carriage braces seat top better.
> (A quick way to cut excess boat weight).
> 3. S/A is usually a lower structure than D/A - enhances boat stability
> by lowering C of G.
> 4. On good (stainless, correctly-greased & sealed) integral-bearing
> wheel assemblies, S/A seats generally take several years in typical club
> use on non-saline waters before bearings get crunchy. Wheels are then
> easily replaced at modest cost. Salt water use may reduce bearing life.
> (With bad bearings, & there are plenty around, life will be short in any
> water. Yet the cost difference between good & bad is minimal).
> 5. S/A seats are normally far harder to dislodge than D/A - left in the
> boat they stay in the boat.
>
> But you do still have to pull that oar
> --
> Carl
> from Carl Douglas Racing Shells
> URL http://www.rowing-cdrs.demon.co.uk
The only real advantage D/A seats have over S/A ones is that they can hang
over further at the top of the slide. If your calves hit the slides at
the finish and you are using a S/A seat switching to a D/A seat will help
because the slide tracks can be adjusted toward the bow giving your calves
more clerance.
I use a S/A for all of the above reasons that Carl mentioned.
--
Jim Dwyer
London, Ontario
Canada
Tony Curran
Jim,
I have a Vespoli single and experienced that crunchy feeling with my
seat. I wasn't at all happy with the carbon fibre seat Vespoli makes, as
it creaked and groaned under my 205 lbs so I replaced it with a Carl
Douglas Lo-Glide seat. This seat is smooooooth and comfortable, even
without seat pad. Well worth the $140 Cdn I apd for it.
Tony Curran
Ottawa RC
Tony Curran
without seat pad. Well worth the $140 Cdn I paid for it.
Tony Curran
Ottawa RC
Ken
IMHO, tall rowers with big feet have no real choice and must opt for
the extra 3" the double action seat gives them, even with adjustable
tracks.
Having long legs requires the stretcher to be far aft, which results
in tall rowers sliding furthest aft at the catch. Having big feet
requires the heel cups at the lowest position. This combo puts tall
rowers' calves closest to the end of the seat deck (or, rather, the
most impacted by the edge of the seat deck). With double action, a
tall rower's calves already touch tracks that end at the edge of the
seat deck. With single action, the tracks would jut 3" into his
calves.
Ken Cooperstein
Jim Dwyer
That is another advantage I never would of thought of because I am only
174 cm tall!
JSlack
Ken wrote:
>
> IMHO, tall rowers with big feet have no real choice and must opt for
> the extra 3" the double action seat gives them, even with adjustable
> tracks.
>
> Having long legs requires the stretcher to be far aft, which results
> in tall rowers sliding furthest aft at the catch. Having big feet
> requires the heel cups at the lowest position. This combo puts tall
> rowers' calves closest to the end of the seat deck (or, rather, the
> most impacted by the edge of the seat deck). With double action, a
> tall rower's calves already touch tracks that end at the edge of the
> seat deck. With single action, the tracks would jut 3" into his
> calves.
>
> Ken Cooperstein
With the advent of the winged-rigger I have wondered why the builders
haven't moved the tracks. It seems to me that they could move them out
far enough that they wouldn't even contact the calf.
I have rowed one that did move them out some, but then they hit the
outside of my calves. This was even worse.
Sure seems like the deck could be slightly modified so that the tracks
would go along the splash box. The track could then be extended to what
ever length was needed for a particular rower to roll up. The tracks
wouldn't protrude into the stretcher well.
Just a thought,
jcs
Jim Dwyer
Hudson's wing rigger single has the tracks moved out to the inside of the
splashboards as there is no rib in the way. The tracks are out far enough
that they do not bother my calves in the 1x and but they really chewed up
the guy's in 2 seat in the 8 I am rowing in. The tracks are further
apart in the Hudson 8 as well as there are no ribs to get in the way.
Thrashercl
What are double action seats? Or, perhaps, what is the difference between
single action and double action seats? Thanks
CLT
Ken
-------
From an earlier post:
>Could someone explain the advantages (or disadvantages) of single action
AlexFilRep
Filippi also have moved their tracks farther apart on the new Wingboat shells.
This has been very successful in preventing "boat bite". This is great in
both single-action and traditional seats.
Alex Selvig
"In Filippi veritas"
Jim Kreuziger
JSlack wrote:
Stuff Deleted...
> With the advent of the winged-rigger I have wondered why the builders
> haven't moved the tracks. It seems to me that they could move them out
> far enough that they wouldn't even contact the calf.
>
> I have rowed one that did move them out some, but then they hit the
> outside of my calves. This was even worse.
>
> Sure seems like the deck could be slightly modified so that the tracks
> would go along the splash box. The track could then be extended to what
> ever length was needed for a particular rower to roll up. The tracks
> wouldn't protrude into the stretcher well.
>
> Just a thought,
> jcs
I have also wondered about this also, but while reading this thread,
another idea popped into my head. Why not make the tracks flush
with the surface of the seat deck? The seat deck could also be made
to slope like the tracks, and therefore the front part of the deck
would be slightly lower, giving slightly more clearance. Unless
you increased the wheel diameter, one would sit lower in the boat.
Lowering the center of mass would increase stability.
Just a thought.
-- Jim
___________________________________________________________________
Jim Kreuziger Politics: From the greek poly,
Jet Propulsion Laboratory meaning many, and tics,
phone: (626) 306-6605 work meaning bloodsucking parasites.
e-mail: ji...@dareangel.jpl.nasa.gov
___________________________________________________________________
DISCLAIMER: JPL now requires notice in all electronic communication
that
all personal and professional opinions presented herein are my own and
do
not, in any way, represent the opinion or policy of JPL.
Kieran Coghlan
Jim Kreuziger wrote:
>
> JSlack wrote:
>
> Stuff Deleted...
>
> > With the advent of the winged-rigger I have wondered why the builders
> > haven't moved the tracks. It seems to me that they could move them out
> > far enough that they wouldn't even contact the calf.
> >
> > I have rowed one that did move them out some, but then they hit the
> > outside of my calves. This was even worse.
> >
> > Sure seems like the deck could be slightly modified so that the tracks
> > would go along the splash box. The track could then be extended to what
> > ever length was needed for a particular rower to roll up. The tracks
> > wouldn't protrude into the stretcher well.
> >
> > Just a thought,
> > jcs
>
> I have also wondered about this also, but while reading this thread,
> another idea popped into my head. Why not make the tracks flush
> with the surface of the seat deck? The seat deck could also be made
> to slope like the tracks, and therefore the front part of the deck
> would be slightly lower, giving slightly more clearance. Unless
> you increased the wheel diameter, one would sit lower in the boat.
> Lowering the center of mass would increase stability.
>
> Just a thought.
>
> -- Jim
Yeah, Duvall would LOVE that, Jim. Can you imagine how many butt pads
he'd have everybody on? Seriously, though, I don't know if that would
be a good idea, since you'd then have to change the rigging quite a bit,
in order to keep the rower from pulling into his/her teeth. But then,
if you did that, the oar would be too close (low) to the water, and it
would be hard to get it out at the finish. On your idea, however, why
not raise the deck to the level of the tracks instead of vice-versa?
That would achieve the same thing, no?
On the other hand this all may be moot, since Resolute has apparently
solved the problem. They have extra wide tracks, and cut-outs in the
deck in which your calves fit. Never rowed one, but it looked pretty
good to me.
------------------------------------------------------------------
Kieran Coghlan, Mechanical Engineer, The Boeing Company
Cal Irvine Rowing, '92-'96
------------------------------------------------------------------
"...The proper function of man is to live, not to exist.
I shall not waste my days in trying to prolong them.
I shall use my time." --Jack London
------------------------------------------------------------------
Views expressed are not necessarily those of The Boeing Company.
------------------------------------------------------------------
Brian E.
The tracks are MUCH nicer compared to the other Filippi's out there (at
least my legs think so). Now if I could only sit on the seat for more
than 20 minutes without having to lift myself up to bring back some
circulation, it would be PERFECT.
BJE
RIKAAA
>Subject: Re: Single vs. Double Action Seats
>From: Jim Kreuziger <ji...@dareangel.jpl.nasa.gov>
>Date: Thu, 18 Sep 1997 17:03:37 -0700
>Message-id: <3421C1...@dareangel.jpl.nasa.gov>
>
>JSlack wrote:
>
>Stuff Deleted...
>
>> With the advent of the winged-rigger I have wondered why the builders
>> haven't moved the tracks. It seems to me that they could move them out
>> far enough that they wouldn't even contact the calf.
>>
>> I have rowed one that did move them out some, but then they hit the
>> outside of my calves. This was even worse.
>>
>> Sure seems like the deck could be slightly modified so that the tracks
>> would go along the splash box. The track could then be extended to what
>> ever length was needed for a particular rower to roll up. The tracks
>> wouldn't protrude into the stretcher well.
>>
>> Just a thought,
>> jcs
>
>I have also wondered about this also, but while reading this thread,
>another idea popped into my head. Why not make the tracks flush
>with the surface of the seat deck? The seat deck could also be made
>to slope like the tracks, and therefore the front part of the deck
>would be slightly lower, giving slightly more clearance. Unless
>you increased the wheel diameter, one would sit lower in the boat.
>Lowering the center of mass would increase stability.
>
>Just a thought.
>
>-- Jim
>___________________________________________________________________
>Jim Kreuziger Politics: From the greek poly,
>Jet Propulsion Laboratory meaning many, and tics,
>phone: (626) 306-6605 work meaning bloodsucking parasites.
>e-mail: ji...@dareangel.jpl.nasa.gov
>___________________________________________________________________
>
>DISCLAIMER: JPL now requires notice in all electronic communication
>that
>all personal and professional opinions presented herein are my own and
>do
>not, in any way, represent the opinion or policy of JPL.
>
>
>
First thing that popped into my mind (i.e. limited as it is from too much
rowing) is: Who is this guy, some rocket scientist?
JSlack
RIKAAA wrote:
>
> >Subject: Re: Single vs. Double Action Seats
> >From: Jim Kreuziger <ji...@dareangel.jpl.nasa.gov>
> >Date: Thu, 18 Sep 1997 17:03:37 -0700
> >Message-id: <3421C1...@dareangel.jpl.nasa.gov>
> >
> >JSlack wrote:
> >
> >Stuff Deleted...
> >
> >
> >I have also wondered about this also, but while reading this thread,
> >another idea popped into my head. Why not make the tracks flush
> >with the surface of the seat deck? The seat deck could also be made
> >to slope like the tracks, and therefore the front part of the deck
> >would be slightly lower, giving slightly more clearance. Unless
> >you increased the wheel diameter, one would sit lower in the boat.
> >Lowering the center of mass would increase stability.
> >
Only see one problem with this; Any debris (including sand) would end
up in the seat tracks. They would be the lowest point of the seat deck.
jcs
Jim Kreuziger
RIKAAA wrote:
Stuff deleted...
>
> First thing that popped into my mind (i.e. limited as it is from too much
> rowing) is: Who is this guy, some rocket scientist?
Actually, no, I'm not a rocket scientist. I'm just a guy with
a B.S. in Physics working as a software engineer. This allows
me the following:
1. Not enough time on the water rowing. Anybody that knows
the LA/Orange County area knows how far Pasadena is from
Newport Beach (64 miles from office to boathouse).
2. Way too much time on the freeway to think about these
sort of issues.
3. Lunch hours and break times spent reading rec.sport.rowing.
4. Just enough scientific/engineering knowledge to be either
stupid or dangerous, quite possibly both.