Question about prop

May 20, 2019
4
S2 9.2 In Northeast
I just bought my first sail boat, it’s a 1981 S2 9.2 with the 15hp yanmar (2GM). It’s in great shape overall, I’ve been extremely lucky for her age. I have been told by a few people that the only issue is that it’s under powered...(can’t fix that now) but also was told that the 2 blade prop is not as effective as a 3 blade. I’ve found that the YGM can have either the 14x11 or the 15x9 on 3 blade. I guess my question is mostly about practicality, I was told that the 3 blade makes it more manageable and maneuverable under power. Does it make a difference really? If it does is the shaft 1”? Or 1 1/8” I didn’t have my caliper when I was at her last, but to my eye it’s at least 1”. I would be able to do this on my own but my tools at school are in Rhode Island, I live in Mass, and the boat is on the hard in Conn, and I drive a 2 seater...so it’s hard to have everything I need when I’m going between all of that. Any info I can receive would be greatly appreciated.
 

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Last edited:
Oct 22, 2014
21,076
CAL 35 Cruiser #21 moored EVERETT WA
@Will423 It appears that you are Thinking about a propeller change.
The first question is how do you want to use your boat?
  • If sailing perhaps racing is the dominate use then a 2 blade prop is going to give you improved sailing experience. With the blade in line with the keel you got reduced prop drag which means improved sailing speed.
  • If you are doing a lot of power cruising with conditions of high currents or expecting to frequently be in heavy weather conditions under power then perhaps a 3 bladed prop can provide a little improvement under power but you will sacrifice sailing speed.
Boats are a series of compromises. Only you can decide which side to favor and which to give up.

An additional option is a folding or feathering prop. This will mitigate some of the limits of the fixed blade prop. These come with a price tag.

It is your boat and your choice. Choose wisely.
 
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Likes: Justin_NSA
May 20, 2019
4
S2 9.2 In Northeast
Thank you for the input. The boat has a fixed 2 blade prop already. So from what I’ve been told there shouldn’t be much more drag with the 3 vs the 2. A feathered prop is not an option for me right now, but a 3 blade is for nothing. I will be doing quite a bit of motoring when I take her from Newport down the Eastern Seaboard. I may change it later but I’m thinking the extra control during my trip down will be worth it. Again thank you for the input.
 
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Likes: jssailem
Nov 10, 2018
35
S2 9.2a Marblehead, Massachusetts
Congrats on the boat. I am in Marblehead and there are not too many S2s around...Mine is my first boat too. Would love to know how you make out with the prop.
 
May 20, 2019
4
S2 9.2 In Northeast
I went to her a few days ago, the prop I was given would’ve worked, but I just didn’t have the materials I needed to get it off, it’s launching in 2 weeks so I’m concentrating on other things. My problem is that I’m Newport, Rhode Island going to IYRS, I currently live aboard a boat in Massachusetts, and my boat is at a Marina in Connecticut. I have a small 2 seater car so it’s difficult to get everything I need when I’m driving 2 hours to get to her. Once she’s launched she will be right in the harbor next to my school so I’ll have all my tools and more close. I love the boat though. Thanks
 

BobM

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Jun 10, 2004
3,269
S2 9.2A Winthrop, MA
Been there and got that tee shirt. My boat was in Milford CT when I bought it. I trucked back and forth for weeks doing a bunch of stuff that people "thought I should do", but at least I had a pickup truck!
 
May 20, 2019
4
S2 9.2 In Northeast
When I get settled in Mobile I’ll be buying a truck for work..but right now I’m just trying to “stay afloat” figuratively...and hopefully never literally
 
Jan 7, 2011
4,751
Oday 322 East Chicago, IN
I have had the 2GM20F Yanmar in my last 2 boats...1990 Hunter 280 and my current 1988 O’Day 322.

I am on Lake Michigan, so I don’t have to fight any currents, but I find the engine pushes the boat ok. I run a fixed 2-blade prop and it pushes the boat at 6+ knots pretty easily.

Greg