2012 Olympic male athletes’ weight [OC]Submitted by highcharts t3_107908x in dataisbeautiful
MeatierShowa t1_j3malqs wrote
Reply to comment by RowBull in 2012 Olympic male athletes’ weight [OC] by highcharts
>heavier your boat is the more drag you will generate
Not according to this. https://www.rowinginmotion.com/drag-efficiency-rowing/
"the drag force attacking the hull is proportional to the square of boat velocity and a hull-specific drag constant ."
Fossafossa t1_j3md04j wrote
More weight = sitting lower in the water = more wetted surface.
The more wetted surface of the boat the more drag it creates.
pitooey123 t1_j3nbn9g wrote
Not necessarily, the boats are rated for certain weight classes so they have different buoyancy
Coomb t1_j3o1j3f wrote
It is absolutely true that any particular boat will sit lower in the water if it's carrying more weight.
Itslikelennonsaid t1_j3oga2c wrote
I feel strongly about this. You are correct.
Deto t1_j3ov4y5 wrote
Yep, if you take a boat and add weight the boat will sink until the additional water it has displaced equals the additional weight.
oak_pine_maple_ash t1_j3p29qa wrote
in rowing the boats are designed around athlete's weights. So my boat is designed for a 130lb person, and my bf's is designed for a 180lb person. It's both longer and wider. We end up sitting around the same height off the water.
SomethingMoreToSay t1_j3qa7hh wrote
Yes, but his has more wetted surface because it's longer and wider, hence more drag.
[deleted] t1_j3ph1e5 wrote
[deleted]
Korvensuu t1_j3qqt1w wrote
as a simple example, you and your bf now swap boats
the lw boat your bf is in will be deeper in the water than when you were in it >> more drag
his boat that you're in now sits higher in the water >> less drag
the boats are designed for different weights but thats not really what we're looking at here, we want to know how much water is displaced as that determines the amount of water-boat surface contact surface area and hence the drag.
A scull rated to a heavier weight does this by being wider and/or longer, increasing the water-shell contact area [which is the key thing as by spreading your bfs weight over a larger area the boat 'sinks' less and has the right water clearance] and increasing the drag
Coomb t1_j3sac93 wrote
You sure do, or at least I believe that you do. That doesn't change the fact that in order for the boat not sink, it has to displace slightly more than the weight of water equivalent to the weight of the boat plus all of its occupants. For any given boat, if you put more weight in it, it must displace more water (or be able to provide additional dynamic lift, but that's irrelevant for rowing sculls). Your boat and your boyfriend's boat have approximately the same freeboard, but his boat absolutely must have additional volume displaced below the waterline, and that necessarily induces additional drag.
KrzysziekZ t1_j3p8hdn wrote
More wetted area or cross section must result in more drag. However, some if not more drag is wave-making drag (which is harder to model) and this is primarily dependent on length of the hull, which doesn't change with displacement.
MeatierShowa t1_j3r37a4 wrote
The length of the hull doesn't change, but the waterline might, depending on hull shape. I think it's known in sailboats that if you load it down to increase the waterline you might get a little higher hull speed.
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