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Old 04-25-2013   #451
 
Redmond, Oregon
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Quote:
Originally Posted by followthebubbleline View Post
But are you really gaining anything? You may be getting more power in your stroke but you're also losing stroke length and arms can only move so fast. I'd say this is a wash. The other thought is, what does 6" matter in a 2000 lb boat with 15,000 cfs pushing you around?
There are people who have looked at this from all the angles.
I don't want to hint even remotely that I have a clue.

from:
Quote:
Volume 11 No 121 Rowing Biomechanics Newsletter April 2011
Quote:
Conclusions:
Total angle of 114 deg (catch 68-70 deg, finish 44-46 deg) appears to be the optimal for achieving the maximal boat speed in sculling.
Rigging dimensions should be adjusted based on the rower’s height and actual length of the arc to obtain the optimal rowing angles (2).

http://www.biorow.com/RBN_en_2011_fi...BiomNews04.pdf
I guess one point of emphasis I'm seeing is that one can bite off more than they can chew. Its not just how much leverage is possible.

In regards to what we are talking about primarily, oar lock placement. They have already determined that in the case of teams. The above paper was just dealing with what length oars were best for any given persons height.

Perhaps they aren't all that impressive in their analysis. They just looked at a persons height and not upper body length / arm span.

==========

I certainly don't know this but I would tend to think that 6" does matter in a 2000 lb boat with 15,000 cfs pushing it around. I suspect there may be posters here who have studied this on their boats and found an optimal angle out for their oarlock stands for themselves.

This is actually complicated to my little brain.
The variables.

Oar Length
Oar lock placement on boat
fulcrum placement on oar
Rowers arm span
Rowers arm strength
Rowers thigh strength
Loaded boat weight
Draft
Rowers height above oarlocks in conjunction with overall height above the water
A sliding seat to better use ones thighs than arms????
Looking at all of the above for compatibility with different strokes
Placement of oarlocks midline or rear of boat
Other stuff


= = = = = = = = = = =

Trying to understand the recreational industry and all of this it occurs to me that the boats have been relatively highly developed but not so the frames.

Some light reading for tonight:

High Performance Rowing - Resources


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Old 04-25-2013   #452
 
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portland, Oregon
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Quote:
Originally Posted by BilloutWest View Post
There are people who have looked at this from all the angles.
I don't want to hint even remotely that I have a clue.

from:




I guess one point of emphasis I'm seeing is that one can bite off more than they can chew. Its not just how much leverage is possible.

In regards to what we are talking about primarily, oar lock placement. They have already determined that in the case of teams. The above paper was just dealing with what length oars were best for any given persons height.

Perhaps they aren't all that impressive in their analysis. They just looked at a persons height and not upper body length / arm span.

==========

I certainly don't know this but I would tend to think that 6" does matter in a 2000 lb boat with 15,000 cfs pushing it around. I suspect there may be posters here who have studied this on their boats and found an optimal angle out for their oarlock stands for themselves.

This is actually complicated to my little brain.
The variables.

Oar Length
Oar lock placement on boat
fulcrum placement on oar
Rowers arm span
Rowers arm strength
Rowers thigh strength
Loaded boat weight
Draft
Rowers height above oarlocks in conjunction with overall height above the water
A sliding seat to better use ones thighs than arms????
Looking at all of the above for compatibility with different strokes
Placement of oarlocks midline or rear of boat
Other stuff


= = = = = = = = = = =

Trying to understand the recreational industry and all of this it occurs to me that the boats have been relatively highly developed but not so the frames.

Some light reading for tonight:

High Performance Rowing - Resources


Bill you lost me at Quote: ...

you could go through 1000 iterations trying to find the optimal setup, or you can spend your time on the river and make modifications as you go ...

I'm gonna have a brewski and ponder how much I must look like that crew member when I'm on the rio ....
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Old 04-25-2013   #453
 
Redmond, Oregon
Paddling Since: 1973
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Originally Posted by Avatard View Post
Bill you lost me at Quote: ...
I'm lost myself.

In the USFS there were two words not to be used on the radio.
Lost and stuck.

I'm getting my bearings is preferred in this scenario.

=======

A lot of this is covered in the recent Illinois video.

Illinois video from last weekend

The Captain in a non seat, on a cooler or dry box, can slide when more power is needed and we do that a little naturally. Thighs are the most powerful muscle we have so using thighs more seems like a good tactic.

Not having a Captain seat also allows for some extra movement to clear oars being shipped forward in tight straits.

A smaller boat means oar handles closer together to get decent leverage.
Individual rowers in Crew will have their handles one above the other in a clumsy fashion that they learn out of necessity.

I don't know this but I think the strongest natural motion is to pull toward the armpits. Pulling narrow or wide I don't think we are as strong. Test yourself at the gym and beat me up if I'm wrong.

With all the ammo cans in the Illinois Captains bay and the narrow boat with those longish oars the Illinois Captains are kind of in a scull.

==========

Was hoping to be able to make a frame that is exactly what I want the first time. Given any boat to work with.

I can do that with regard to bays for gear stowage.
By studying all the suggestions here then thinking it over for several months.

There is no way I can do that with seat oar lock oar length other related stuff considerations.
My 61 year old brain is continuing to shrink and without someone setting up a fill in formula I'm toast. Rats, foiled again.

Going to have to stay flexible as constantly advised here.
Understood

========

For now, until some post here convinces me otherwise, I want to row stronger with a sliding seat on a double rail that arcs down to mounts on the bay below the Captain. It will need a rear release and flip feature of course.

Rowing now like we often do is using our backs and arms.
Did I mention my back issues?
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Old 04-25-2013   #454
 
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Too much talk, not enough porn!
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Old 04-25-2013   #455
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Still working on it

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Old 04-26-2013   #456
 
Redmond, Oregon
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Porn formula

Quote:
Originally Posted by TriBri1 View Post
Too much talk, not enough porn!


Quote:
The oars as a result of using this formula will not require overlapping hands on the pull part of the stroke. Only in the recovery part of the stroke will there be hand overlap, 2" of overlap to be exact.
Oars & Rowing Article - Maine Boatbuilder + Repairer Wood + Plywood Boats Oarmakers Birdsmouth Mast + Sparmakers Foils Boat Plans + Kits

===========

The Oar Length Formula Step-by-Step

1) Measure pin-to-pin span for the rowing station

2) Divide span by 2 and add 2" to compensate for freeboard

3) Divide by 7.

4) Multiply by 25 to get oar length in inches.

5) Divide by 12" to get oar length in feet and tenths of inch.

6) Round to nearest whole inch.

=================

In summary:
THE DRIVE: legs --> back --> arms
THE RECOVERY: arms --> back --> legs
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Old 04-26-2013   #457
 
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Quote:
Originally Posted by BilloutWest View Post




Oars & Rowing Article - Maine Boatbuilder + Repairer Wood + Plywood Boats Oarmakers Birdsmouth Mast + Sparmakers Foils Boat Plans + Kits

===========

The Oar Length Formula Step-by-Step

1) Measure pin-to-pin span for the rowing station

2) Divide span by 2 and add 2" to compensate for freeboard

3) Divide by 7.

4) Multiply by 25 to get oar length in inches.

5) Divide by 12" to get oar length in feet and tenths of inch.

6) Round to nearest whole inch.

=================

In summary:
THE DRIVE: legs --> back --> arms
THE RECOVERY: arms --> back --> legs
I hate to tell you, but that formula is way off.....at least for rafting. Using that formula, I'd need 11 ft. oars for my little 12 ft. long 6 ft. wide raft. I have 70 inches between oar towers. I found this formula on River Connection and it worked out to exactly the oars I'm using on that raft.

Formula: Distance between the Oar Locks X 3 - 6", Divided by 2, Divide by 12 to get feet. Example: 80" X 3 = 240 - 6" = 234 divide by 2 =117, divide by 12 = 9.75. You would need a 10' Oar. Always round up to the next number.

Sorry.....I know that wasn't porn. But the oar length thing has been plaguing me lately. I tried 8 ft. oars on this boat when I first set it up in my garage. They seems too short to me. I adjusted the oar towers several times, and still didn't feel right. I have suffered from "too short oar syndrome" before. Switched out to 8.5 ft. and they feel perfect. The formula above validated my choice of 8.5 ft. oars.

More porn pics after next week. My new little Hyside will take it's Maiden Voyage on Deso next week.
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Old 04-26-2013   #458
 
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70" between oarlocks seem a bit wide for a 12' boat. Maybe your boat geometry is messed up?

My buddy has a 13' SB. He runs a 60" single rail NRS frame (66" between towers) and 9' oars. I've rowed it --It feels about right
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Old 04-26-2013   #459
 
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Quote:
Originally Posted by Avatard View Post
70" between oarlocks seem a bit wide for a 12' boat. Maybe your boat geometry is messed up?

My buddy has a 13' SB. He runs a 60" single rail NRS frame (66" between towers) and 9' oars. I've rowed it --It feels about right
Geometry is good. I'm using the 10 inch towers, so I could lean them outward more. Plus I'm sitting up on a dry box to row. Not that much difference from your friends 66 inch oar spread & 9 ft. oars. 8 inch oar towers and 8 ft. oars didn't feel right. When I got the oars balanced (2/3 out, 1/3 in) my rowing position didn't feel right. As I said, I've suffered with oars that were too short before, and I didn't want to go there again. With the taller oar towers I was able to get a wider width, better balance, and better oar position. I use taller towers and 9.5 ft. oars on my cat with the 66 inch NRS frame and it works perfectly. The raft is now set-up in a similar fashion. We shall see next week when I hit the water.
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Old 04-26-2013   #460
 
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Originally Posted by cataraftgirl View Post

Geometry is good. I'm using the 10 inch towers, so I could lean them outward more. Plus I'm sitting up on a dry box to row. Not that much difference from your friends 66 inch oar spread & 9 ft. oars. 8 inch oar towers and 8 ft. oars didn't feel right. When I got the oars balanced (2/3 out, 1/3 in) my rowing position didn't feel right. As I said, I've suffered with oars that were too short before, and I didn't want to go there again. With the taller oar towers I was able to get a wider width, better balance, and better oar position. I use taller towers and 9.5 ft. oars on my cat with the 66 inch NRS frame and it works perfectly. The raft is now set-up in a similar fashion. We shall see next week when I hit the water.
If your towers are sticking out near the edge of the boat, and you broadside a rock (with oars shipped) it will be interesting to learn if you get any damage to the shaft, lock, or tower

With my situation, there is at least about 8" of tube to act as a bumper

Normally the nrs towers will spin a bit under duress. With a steeper pitch this might lose a little of that give

What sort of angle do you have on those towers? Too much and your oarlocks may tend to pinch the oars.
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