Water Level to Seat Height

Water Level to Seat Height

Post by rubcsi.. » Wed, 27 Feb 2013 18:56:05


Some club mates of mine are looking at possibly building a rowing tank, and are trying to establish dimensions for it. They have got figures for most numbers and adjustment ranges they'll need for the rig, however they've been stumped by what the difference in height between the seat and the water level should be. Is there are hard and fast rule for this? I imagine in a boat this will vary depending on how the crew weight is in comparison to the weight the boat was built for, but presumably there should be a rough range for this measurement. If anyone can help out on rough numbers for this, that would be great!

Cheers,

Simon

 
 
 

Water Level to Seat Height

Post by wmart.. » Fri, 01 Mar 2013 03:08:42

Quote:

> Some club mates of mine are looking at possibly building a rowing tank, and are trying to establish dimensions for it. They have got figures for most numbers and adjustment ranges they'll need for the rig, however they've been stumped by what the difference in height between the seat and the water level should be. Is there are hard and fast rule for this? I imagine in a boat this will vary depending on how the crew weight is in comparison to the weight the boat was built for, but presumably there should be a rough range for this measurement. If anyone can help out on rough numbers for this, that would be great!

> Cheers,

> Simon

Assuming you're not frozen off the water (yes, ass/u/me)  can you not take a few different "properly boated" crews out and take some measurements?  Spirit level across the gunwales, measure down to the seat and measure down to the water?  take the average and there you go?  
You could e-mail Carl Douglas, Hudson Boat Works, Kaschper Racing Shells, Empacher, Vespoli, Fluidesign, Filippi, Sykes, KIRS, or perhaps quite a few others and see what (if they reply at all) they say.

 
 
 

Water Level to Seat Height

Post by sull » Sat, 02 Mar 2013 03:14:18


Quote:
> Some club mates of mine are looking at possibly building a rowing tank, and are trying to establish dimensions for it. They have got figures for most numbers and adjustment ranges they'll need for the rig, however they've been stumped by what the difference in height between the seat and the water level should be. Is there are hard and fast rule for this? I imagine in a boat this will vary depending on how the crew weight is in comparison to the weight the boat was built for, but presumably there should be a rough range for this measurement. If anyone can help out on rough numbers for this, that would be great!

> Cheers,

> Simon

I keep forgetting to measure in the morning since you asked a couple
days ago.   there's a couple inch range from different boats,  but my
eyeball guess is 6-7 inches.

 
 
 

Water Level to Seat Height

Post by Carl » Sat, 02 Mar 2013 04:00:48


Quote:

>> Some club mates of mine are looking at possibly building a rowing tank, and are trying to establish dimensions for it. They have got figures for most numbers and adjustment ranges they'll need for the rig, however they've been stumped by what the difference in height between the seat and the water level should be. Is there are hard and fast rule for this? I imagine in a boat this will vary depending on how the crew weight is in comparison to the weight the boat was built for, but presumably there should be a rough range for this measurement. If anyone can help out on rough numbers for this, that would be great!

>> Cheers,

>> Simon

> I keep forgetting to measure in the morning since you asked a couple
> days ago.   there's a couple inch range from different boats,  but my
> eyeball guess is 6-7 inches.

Deliberately working from memory -

A typical 8+:
Waterline is about level with slide-beds.
Slide-beds ~190mm below sax tops.
Seats (lowest contact point on top) ~120mm below sax tops (here
considering conventionally-rigged shells, whose free-board significantly
exceeds that of the cut-down, & thus much wetter, wing-rigged jobs).
Oarlocks ~175mm above seats.

Gives you these values:
Seats ~70mm above waterline
Oarlocks ~245mm above waterline
All very much 'ball-park' stuff

Then go to a 1x:
Seat ~100mm above waterline
Oarlocks ~175mm above seat
So oarlocks ~275mm above waterline

With a single you're constrained by the shallowness of the hull - feet
mustn't go through the bottom!  Which helps explain the differences seen
above.  And then there's the popular doctrine demanding a large
seat/feet height differential - "So you can get your weight over your
feet at the catch", goes the somewhat irrational mantra.

And from time to time I get folk trying to prescribe oarlock-to-water,
seat-to-feet & seat-to-oarlock differentials, having read this from some
book without understanding the inherent constraints imposed by the
realities of boats.

HTH -
Carl

--
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