[Public-List] Public-List Digest, Vol 3998, Issue 4 Two blades prop

[Gordon Laco]

Yep

Sent from my iPhone

> On Apr 26, 2020, at 7:41 PM, Greg Aldworth via Public-List <public-list at lists.alberg30.org> wrote:
> 
> The prop will “windmill” with the engine in neutral. The vessel is moving forward under sail and water is flowing past the prop. With the 3 bladed prop, there will always be enough prop. surface area exposed to keep it spinning. I think with a 2 bladed props, they tend to lose thrust when in the shadow of the keel. 
> I have a larger motor vessel and if we shut down one engine, that prop will windmill when we are underway. 
> Does this sound right Gord?
> Greg 
> 
> Sent from Mail for Windows 10
> 
> From: Greg Hounsell via Public-List
> Sent: April 26, 2020 6:49 PM
> To: Alberg 30 Public List -- open to all
> Cc: Greg Hounsell
> Subject: Re: [Public-List] Public-List Digest, Vol 3998, Issue 4 Two blades prop
> 
> I don't understand how a prop would cause rotation when in neutral. Is
> there a strong tide or current?
> 
> Greg
> #592
> 
> On Sun, Apr 26, 2020, 6:06 PM Daniel Swords via Public-List <
> public-list at lists.alberg30.org> wrote:
> 
>>    The PO of my boat had replaced the original two blade prop with a
>> three blade prop, but fortunately had saved the original. I disliked the
>> three blade so much that I paid to have the boat hauled just to replace it
>> with the original two blade.
>> 
>> 
>> 
>>    If left in neutral the three blade spun continuously and noisily and
>> created enough turbulence to feel through the tiller. If left in gear
>> (something Yanmar recommends against) the transmission would lock-up with
>> even the slightest forward motion such that the safety interlock would
>> prevent starting the engine.     As far as I can tell the two blade prop
>> does not spin in neutral and typically parks vertically behind the keel.
>> Also, I did not notice any significant advantages with the three blade prop
>> so I gave mine away and have never considered going back.     Currently
>> sailing on Lake Pontchartrain, winds 15 gusting to 19 knots, double reefed
>> main and 110% jib. Daniel SwordsSolitude, Hull #525Mandeville, Louisiana
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