[Rhodes22-list] Centerboard Drag and 6hp Speed

[ROGER PIHLAJA]

Hi Lee,

Based on the % throttle required to maneuver my boat in strong head and cross winds,  I estimate the minimum required power is about 4 bhp.  But again, this assumes the prop is submerged deeply enough to not cavitate in the troughs between waves.  If you have to throttle back because of cavitation; then, all bets are off.

Roger Pihlaja
S/V Dynamic Equilibrium   

Sent from my iPhone

> On Jun 26, 2022, at 4:48 PM, Lee Kuhn <lvjkuhn at gmail.com> wrote:
> 
> Hey Roger,
> 
> I wanted to go with the 3hp electric but I  thought it might not be enough.
> 
>> On Sun, Jun 26, 2022, 4:37 PM ROGER PIHLAJA <roger_pihlaja at msn.com> wrote:
>> 
>> Hi Lee,
>> 
>> S/V Dynamic Equilibrium came with an Evinrude 6 bhp long shaft outboard.
>> It was OK; but, when it came time to replace it, I opted for an extra long
>> shaft Honda 8 bhp.  The 6 bhp outboard was plenty powerful enough to power
>> the boat against any headwinds.  But, with the wind come waves and the 6
>> bhp long shaft Evinrude would frequently cavitate.  The extra long shaft
>> Honda was a significant improvement.  If an extra long shaft 6 bhp outboard
>> had been available, I would have considered it.  All the power in the world
>> is of no use if you can’t couple it to the water.  Attached is a photo of
>> the stern of my boat with the motor mount in the fully lowered position.
>> Note how the prop is well below the waterline.
>> 
>> [cid:image003.jpg at 01D8897B.1DDD8870]
>> 
>> Roger Pihlaja
>> S/V Dynamic Equilibrium
>> 
>> 
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>> 
>> From: Lee Kuhn<mailto:lvjkuhn at gmail.com>
>> Sent: Sunday, June 26, 2022 9:48 AM
>> To: The Rhodes 22 Email List<mailto:rhodes22-list at rhodes22.org>
>> Subject: [Rhodes22-list] Centerboard Drag and 6hp Speed
>> 
>> 1.  I was motoring around the lake the other day trying to get the ten
>> hours of break-in period on my new outboard.  That's a lot of motoring when
>> I could have been sailing.  I was going 3.5 mph with the diamond
>> centerboard in the up position.  I lowered the board and it slowed me down
>> to 3.4 mph.  May not be surprising to a lot of you but I'd thought it would
>> have slowed the boat down morre.
>> 
>> 2,  My old motor was a 9.9hp.  I thought that a 8hp would be ideal for our
>> boats but I went down to a 6hp because of the weight difference,  Not sure
>> if I can manhandle the smaller engine on and off the boat but I can
>> probably find some kid who can.  At slightly less than one third throttle
>> the Tohatsu long shaft moved the boat at 5.1 mph in calm waters.  It will
>> be interesting to see what it can do in a strong headwind.
>> 
>> Lee
>> 1999 Rhodes22  AT EASE
>> Claytor Lake, VA
>> 
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