T-Pain Is On A Boat: Re: [Electric Boats] Static Thrust was Re: Trolling Motors

Monday, August 3, 2009

Re: [Electric Boats] Static Thrust was Re: Trolling Motors

Denny,

Thank you for your explanation. Glad to hear your confirming my priorities -
I don't have that much windage, but trying to maneuver when the winds are
over 25 knots is interesting, when over 35 is challenging, when over 45 is
hair-raising! :-)

Joe

> From: dennis wolfe <dwolfe@dropsheet.com>
> Reply-To: <electricboats@yahoogroups.com>
> Date: Mon, 3 Aug 2009 16:26:59 -0400
> To: <electricboats@yahoogroups.com>
> Subject: Re: [Electric Boats] Static Thrust was Re: Trolling Motors
>
> My comment about static thrust not being a very relevant criteria is because
> most E boaters want to go as fast as possible with as little energy expended
> as possible. There is a presumption that motors of equal static thrust have
> equal ability to drive the boat at design speed. I believe this is the
> 'logical' basis behind the 1 electric hp = 2 or 3 or 5 ICE hp nonsense.
>
> If you are mostly concerned about accelerating your boat from a standstill or
> overcoming a huge amount of windage then static thrust is relevant.
>
> Denny
>
> ----- Original Message -----
> From: Joe Siudzinski
> To: electricboats@yahoogroups.com
> Sent: Friday, July 31, 2009 5:47 PM
> Subject: [Electric Boats] Static Thrust was Re: Trolling Motors
>
>
>
> dennis wolfe <dwolfe@dropsheet.com> wrote:
> (snip)
>
>> Its static thrust (bollard pull) is not relevant to how fast it will push the
>> boat. Thrust is a stupid way of comparing motors as the boats are not used
>> tied to a stationary dock.
>
> Denny:
>
> I'd like to explore this a bit, as, on the contrary, I consider static
> thrust a very relevant selection criterion (which, unfortunately, is never
> published by outboard manufacturers). I have two Yamaha 9.9HiThrust gas
> outboard motors on my 36' sailing catamaran which have served me wonderfully
> for seven years of cruising (each has about 2600hours on it). My top speed
> with both engines wide-open is 7.8kts, which, quite frankly, I only did once
> "just to see what she would do". My normal cruising speed is just below
> 5kts.
>
> My criteria is indeed static thrust because over the years I have faced
> situations whereby I had to maneuver the boat in confined spaces into some
> very strong winds whereby the boat is barely moving with the engines wide
> open as you head into and try to turn across the wind. This to me is a most
> important selection criteria as, in my example, an equivalent 9.9hp motor
> with high-speed prop and gearing fails miserably in this situation.
>
> Staying on topic of electric boats, I am exploring adding an electric drive
> (outboard?) as a tertiary drive system since I have excess solar and battery
> capacity. I've been comparing static thrusts for the above reason.
>
> Perhaps you would care to elaborate as to why I'm looking at the wrong
> specs?
>
> JoeS.
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
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