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Sliding riggers
http://www.youtube.com/watch?v=Yq...from Mark, Sat 20th Dec, 10:19pm
For some reason Youtube recommended this video to me (I can only assume from searching for the W1 Lents 2007 video a while ago).

Out of interest is anyone able to explain why this boat has sliding riggers - does it give an advantage, and if so, why?
by JDT - Sun 21st Dec 2008, 12:07am
Sliding rigger boats move a lot faster.
by Martin P - Sun 21st Dec 2008, 3:33pm
I think it should be faster because the majority of weight in a boat is the rowers. The momentum of the rowers means they will tend to move at a roughly constant speed. In conventional boats with sliding seats, the hull speed is therefore varying a lot - surging forward on the recovery and falling back during the power phase. Because skin drag is proportional to velocity to some big power (I believe it is more than 2), a varying hull speed will cause greater power loss than a more constant one. In a sliding rigger boat, the rowers are in a fixed position relative to the hull and so the hull moves along more steadily.

There are people out there who have a better grasp of this and could correct and/or flesh out detail....
by jmg - Mon 22nd Dec 2008, 2:38pm
Martin P said: In conventional boats with sliding seats, the hull speed is therefore varying a lot
Close races would be a lot fairer in sliding rigger boats, with no surge of the bowball at the front end of each stroke, where the phase of a crew's stroke when crossing the line can materially affect the result.
by Simon - Wed 24th Dec 2008, 7:26am
Sliding riggers are also banned from use in competition - think it was deemed to be an unfair advantage for those countries that could afford them? Does anyone know for sure?
by jpd - Wed 24th Dec 2008, 9:25am
Simon said: Sliding riggers are also banned from use in competition - think it was deemed to be an unfair advantage for those countries that could afford them? Does anyone know for sure?
A German sculler won the world championships using sliding riggers some time around 1980. They were immediately banned, I'm pretty sure they cited cost as the main reason.

There hasn't been much research done on them, so the actual advantage is unknown. Using a basic model the advantage could be up to 3% (~6 lengths in a single) but in practice is likely to be closer to 2%.

I would expect a sliding rigger boat to feel quite different to a normal boat. The front end will be lighter and hence will require more skill (a bit like the difference between catching a golf ball and a ping pong ball), but it would probably be a bit easier to press out the finish.
by JDT - Wed 24th Dec 2008, 5:03pm
rowvirusboats.com/virus/sliding_rigger.html

A brief history is here.

A picture of a sliding rigger boat from 1954 is rowinghistory.net/images/ Equipment/SlidingRigger%201955sm.jpg (delete the space)

(Taken from website rowinghistory.net/Equipment.htm )

The above website says that `At the 1982 World Championships 1st through 5th place used sliding-rigger boats while the only sliding-seat boat in the finals placed 6th.'

This website sells sliding riggers that can be fixed to `almost any boat'. http://slidingrigger.net/

They cost $829 for a single sliding rigger part (for picture see above).
by JDT - Wed 24th Dec 2008, 5:16pm
They cost $829 for a single sliding rigger part (for picture see above).
Is this much for a rigger expensive? I haven't really a reference frame for how much these things cost. How much would a normal sculling rigger cost?

It would probably break these things to try and use them for sweeping wouldn't it?
by jpd - Wed 24th Dec 2008, 8:09pm
JDT said: Is this much for a rigger expensive? I haven't really a reference frame for how much these things cost. How much would a normal sculling rigger cost?

It would probably break these things to try and use them for sweeping wouldn't it?
Carl Douglas sculling riggers are 280 GBP. Empacher wing riggers are 595 EUR.

These particular riggers have the wrong span for sweep, and don't look to have much in the way of horizontal stabilisation to counter the torque applied either. I can't think of a reason that would prevent a sweep version working - although I suspect you'd find it quite difficult to feel the rhythm in a crew boat!
by JDT - Thu 25th Dec 2008, 1:04am
I suspect you'd find it quite difficult to feel the rhythm in a crew boat!
Indeed, the advantage of having to move so much weight in the body on the recovery is that you can just break the knees and inertia will keep you in rhythm.

(You've got to pull the rigger and footplate the wrong direction up the boat too -- so no help from inertia at all.)

Also, advice like `keep the distance with the person in front constant' is useless too.

Actually, staying in time sounds pretty difficult. Maybe this is why we only hear of singles doing it.
by Tom C - Thu 25th Dec 2008, 2:01am
JDT said: Indeed, the advantage of having to move so much weight in the body on the recovery is that you can just break the knees and inertia will keep you in rhythm.
Nah, this is what makes us row really short. If you pull yourself up the slide towards the end of the recovery, you can reduce variation in shell speed and get more compression. In a sliding rigger boat you could do pretty much anything on the recovery. Maybe another reason it got banned is that having to change technique favours countries who have lots of money to spend experimenting with minions.
by gf - Mon 29th Dec 2008, 3:23pm
jpd said: [...] I can't think of a reason that would prevent a sweep version working - although I suspect you'd find it quite difficult to feel the rhythm in a crew boat!
Surely a good reason to introduce 1- racing (or even 1+ racing?)... albeit on a course with suitable lane curvature
by jmg - Mon 29th Dec 2008, 4:49pm
gf said: Surely a good reason to introduce 1- racing (or even 1+ racing?)... albeit on a course with suitable lane curvature
or even, rowing deathmatch, where competing athletes (one strokeside and one bowside) are put into a sliding-rigged pair with no rudder and the winner is decided by the side of the course on which they crash.

This might be a little unfair on those at stroke, but I'm sure something could be arranged in a side-by-side configuration a la DeteriorVIII
by Mark - Wed 31st Dec 2008, 11:06pm
I'd like to know how the catamaran boat was put into the water and taken out. I can imagine the usual "to heads" routine when pulling it out would somehow snap bits of the connecting wood/saxboard off.
by JDT - Thu 1st Jan 2009, 12:44am
Tom C said: Nah, this is what makes us row really short. If you pull yourself up the slide towards the end of the recovery, you can reduce variation in shell speed and get more compression.
Thanks, I shall adjust my stroke accordingly.
by JDT - Thu 1st Jan 2009, 12:54am
A single word is too long - maximum length 58 characters - last bit is http://uk.youtube.com/watch?v=MRLgTfH0KI4&feature=related
by dw229 - Thu 1st Jan 2009, 11:48pm
And linked to that is ice rowing. This looks brilliant!

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