From: kork@imagelan.com (Kirk Olsen)
Message-Id: <9503211911.AA06047@imagelan.com>
Subject: Re: Paddling...
To: baidarka@imagelan.com
Date: Tue, 21 Mar 95 14:11:01 EST
In-Reply-To: <9503211001.AA27974@st.unocal.com>; from "Bob Myers" at Mar 21, 95 2:01 am
> Bob.Myers@st.unocal.com wrote:
> On Mar 20, 22:30, Guillemot@aol.com wrote:
> } Subject: Re: Paddling...
The analysis of the paddling motion is going well, at some point
I'm interested in seeing blade design added to the discussion....
> Err - I see what you're talking about now. You're right Nick - I wasn't
> thinking of horizontal force perpendicular to the direction of motion. That
> component is wasted. I was merely thinking of the vertical components,
> which can be compensated for. You can't eliminate the horizontal perpendicular
> components, though.
>
> You can make use of lift by up and down motions, though, *without* creating
> extra vertical drag and rocking the boat. I don't think it's practical to
> do so, though, apart from paddle entry & exit.
Actually the lift can be useful since it decreases the surface area of
the boat and thus decreases the drag on the hull. The trick is paddling
at a speed sufficiently fast that the stroke rate is faster than gravity
settling the hull back down in the water. In essence the boat is bouncing
up and down relative to the water line but if done _properly_ there
is always less hull in the water than the steady state waterline. Lift
generated on a boat sitting still isn't that interesting, the effect
of lift as the boats speed increases gets interesting, at least to me.
kirk