Off Set Prop Shaft : Pros and Cons

[51RD55]

Someone expressed interest in buying our boat and there is a 1972 C&C 35' for sale that was recommended to us to go and see. It has an off set propeller shaft and there seems to be varying opinions about wether or not this is a good feature. Appreciate all thoughts on this please and thank you.

 

[dlochner]

My experience is that this is a non issue. Early Sabres, before the mid 1980s all had offset props. I sailed a 1981 Sabre 30 with a prop that was offset to starboard for about 15 years, never had an issue.

Compared to my current boat with a centered prop shaft, the only difference is the prop walk is less pronounced with the offset prop. But, this isn't really comparing apples to apples as the props are also quite different, a Martec folder on the Sabre 30 and a 3 blade Max Prop on the Sabre 362.

There are a couple of distinct advantages to the offset prop. First, when your dingy painter decides to wrap itself around the prop and shaft, it is much easier to reach it and cut it loose. Second, if you have to remove the shaft the rudder is not in the way.

If you are used to a lot of prop walk and regularly depend on the "back and fill" technique you will have a learning curve, but it is not insurmountable. There are lots of other and better reasons to walk away from a boat.

Some of the older C&Cs had a serious galvanic corrosion issue, not sure if the boat you are looking at has that issue. Seems they put an iron keel on a boat with an aluminum rudder creating a battery in the process. That would be a major issue!

 

[Scott T-Bird]

My offset shaft pushes the boat consistently to port while motoring. It is not that much of a nuisance when I'm steering, but there is constant pressure, which means I can't take my hand off the wheel without applying a brake. I don't know how it may affect an autohelm. There is no issue while sailing.

 

[capta]

I would NOT buy any boat with an offset prop and I have operated a few professionally. They are absolutely the most difficult sailboat to handle, especially in a confined space, because you can only turn ONE way. Backing up is a joke. The prop wash only effects one side of the rudder when it is turned to the prop's side and not at all the other way. Yet while sailing that gear is dragging on one side of the boat, often needing excessive helm to counteract for that drag.
I suggest you give that boat a pass. There are plenty of boats out there that are a lot easier to handle under power and much less likely to get you into trouble in a confined space or difficult current/wind situation.

 

[51RD55]

I would NOT buy any boat with an offset prop and I have operated a few professionally. They are absolutely the most difficult sailboat to handle, especially in a confined space, because you can only turn ONE way. Backing up is a joke. The prop wash only effects one side of the rudder when it is turned to the prop's side and not at all the other way. Yet while sailing that gear is dragging on one side of the boat, often needing excessive helm to counteract for that drag.
I suggest you give that boat a pass. There are plenty of boats out there that are a lot easier to handle under power and much less likely to get you into trouble in a confined space or difficult current/wind situation.

Thanks to all three of you for taking the time to give your feedback.
Capta - Your answer made up our minds! We will pass on this boat. We are new enough to sailing, the last thing we need would be a boat that we would have such trouble handling! Again, many thanks.

 

[Ted]

They are absolutely the most difficult sailboat to handle, especially in a confined space, because you can only turn ONE way.

NOT TRUE (as Trump would say) Being able to turn only one way is totally not an accurate statement. The original poster is new to sailing and he should not base his decisions on comments like that. If you are choosing a boat based on whether or not it has an offset prop shaft you are discounting lots of really fine boats. My previous boat had an offset prop shaft and it behaved perfectly predictably. (it was a C&C 29-2) Make an educated decision by sailing/motoring some boats with and without an offset prop shaft. I would venture to guess that it will be very difficult (if not impossible) for you to tell the difference. There are many more important handling/sailing design aspects to take into consideration such as the type of keel or rudder configuration. Those two will make a substantial difference while handling a boat under power or sail. Sail on as many boats as you can before you discount a entire category of good boats. Don't worry, they will all turn in both directions.

 

[capta]

NOT TRUE .

I did qualify the statement to confined space. How can you argue that? In order to turn against the offset prop you need SPACE, period. In a tight space (marina, canal, river, etc) with wind and/or current you CANNOT use the prop wash across the rudder top kick the stern in both directions, only one. One cannot reliably 'back and fill' with an offset prop.

 

[Capt jgw]

My Columbia 36 has an offset shaft, and the prop is aft of and above the rudder. The Irwin 37 has the same setup. Makes the boat very difficult to handle under power, you have to have way on for the rudder to work at all. It's fine once you're moving, but coming up to a dock can be a real challenge.

 

[Scott T-Bird]

I agree with Ted. In forward, I can't distinguish any difference in turning radius, even at low speed and I have no problems in a confined space. In reverse, it does tend to eliminate prop walk, so back and fill is not effective. With just a little way on, the boat behaves predictably in reverse, without any trouble maneuvering one way or the other. Maybe my smaller boat makes a difference. It's your call, obviously, but Capta's reply did appear to be over-stated and doesn't reflect reality in my opinion. I'm surprised ... I'd guess that a sailor with so much experience wouldn't be that flustered by such a minor distinction.

 

[dlochner]

I too felt that Capta's condemnation of offset props was a little overstated. If you are used to a centerline prop and are used to using a lot of prop wash to maneuver the boat, then the first few times you maneuver a boat with an offset prop might be a little exciting. However, with practice and fore thought, it becomes a non issue in almost all situations. One advantage of offset props is that the prop wash can be used to pull a boat off and away from a dock at the same time when docked alongside opposite the prop shaft. The boat will move diagonally away from the dock rather than along side of the dock as it will with a centerline shaft.

When shopping for a new sailboat there are many more characteristics that are equally or more important than an offset prop, sailing characteristics come readily to mind. Have never heard of anyone complaining about sailing characteristics of a C&C.

With all that said, there is one condition in which an offset prop would cause me to walk away. Early Sabres with props offset to starboard used Volvo engines with a left hand rotation. Most sailboat engines have a right hand rotation. If the boat has been improperly repowered with an engine with the wrong rotation, maneuvering is going to be completely FUBARed, with very exaggerated prop walk. Boats with this issue are fortunately rare and perhaps only the product of over active imaginations.

 

[Scott T-Bird]

I don't know why you wouldn't take a look at a '72 C&C 35 if that is the vintage and type of boat that you are interested in. Based on the attached review, there appears to be a distinction between the MkI and MkII versions. This review seems to be pretty good, and it probably gives you wayyyy more pertinent information to base a decision. It seems pretty silly to make a judgement based on one factor that doesn't even seem to warrant any mention. If your interest is limited to boats of that vintage, there are far more important issues to consider ... perhaps if the boat comes with an original Atomic 4 vs an upgraded or repowered diesel, for instance.
http://www.boatus.com/boatreviews/sail/C&C35.asp

 

[Capt jgw]

I don't think an offset prop would be a enough to reject a boat for that reason alone, just be aware that it may behave a little differently. As long as the prop is forward of the rudder prop wash maneuvered should still work, just better on one side than the other. On my boat with the rudder having no effect on the propwash at all its a little different. I can't do the "Captain Ron" landing like I could with my old boat. It behaves like a boat with an outboard hanging on transom, only its nearly twice the size of most boats set up that way.

 

[Jackdaw]

I would not discount an offset-shaft boat for that reason alone. But it DOES make low speed, tight maneuvering much more difficult. In particular low speed direction changes... as you do not have solid prop wash over the rudder, you have to build boat speed to turn. Twin rudder boats have this same issue and I can tell you there are huge pucker moments on the First 260 and the Pogo when it seems you are never going to turn. How this all factors to you will be based on your abilities and typical docking situations.

 

[mrwrapper99]

My Mirage 33 has an offset engine.

I am not having any problems with any pulling and practically no prop walk. However, it does not give me much steerage in reverse in low speed. The prop is pulling water to the port side of the rudder only and the rudder does not do much in low speed.

 

[LakeOntario270]

My club has many C&C 29's and Sabre 28's and not 1 ever talks about it. Go for it