CD25 Outboard - 6HP Not Enough

[Bob Gephart]

I have replaced my 9.9 Sailmaster with a 6HP Johnson long shaft due to weight considerations. My choice was based on a
Practical Sailor article that said there is no significant difference between a 6 HP and an 8 HP. I have found that I cannot back
against the tide here in Savannah ( 6 - 7 ft normal tide ) with this 6 HP. I could do OK previously with the 9.9, although it was
always tricky. But no way with this 6 HP. I saw a mention of a "sail prop" in one of the previous replies. I cannot find anything
other than the original prop from the OMC dealer here. Can you provide any info on the "sail Prop"????



bgephart@ecc.com

[John Ring]

I have replaced my 9.9 Sailmaster with a 6HP Johnson long shaft due to weight considerations. My choice was based on a
Practical Sailor article that said there is no significant difference between a 6 HP and an 8 HP. I have found that I cannot back
against the tide here in Savannah ( 6 - 7 ft normal tide ) with this 6 HP. I could do OK previously with the 9.9, although it was
always tricky. But no way with this 6 HP. I saw a mention of a "sail prop" in one of the previous replies. I cannot find anything
other than the original prop from the OMC dealer here. Can you provide any info on the "sail Prop"????

Hi There!

The sail prop is what belongs on any sailboat. Our boats will never get above hull speed, 5 or 6 knots or so. The pitch (angle) of the blades has to be in line with this speed, otherwise all you will get is cavitation (boiling of the water on the low pressure side of the blade). I have a CD-25 with a Johnson 8hp and a sail prop. The sail prop looks like a three blade clover leaf. The blades themselves are nearly round, not like the curved elongated blades of a speed prop.The blades are angled to a lesser degree to accomodate a slow moving boat without losing thrust. It does a much better job of getting the power to the water. Backing a Cape Dory 25 is never easy, but I get by with my rig, and we have some big tides around here.
John Ring
s/v Sovereign
Boston



ringj@mediaone.net

[Kurt]

A significant consideration when backing an outboard motor has to do with the design of the exhaust...the 9.9 had it's exhaust in the center of the prop but where is it located on the 6hp you just installed? On the OMC 6's the exhaust will cavitate the prop when running the engine in reverse...changing to a power prop will not help



kjlgpw@aol.com