Changing motor

Jan 6, 2019
24
Nash 26 Ile Perrot Yacht Club
Hello all, I'm new here so please go easy on me. I have a Nash 26 with an OMC Zephyr 2cyl, 2 stroke wigh sail drive from the early 80s and I'd like to change it (mainly because it is noisy, smokey and I think it is coming to the end of its life). I had 3 options going in; electric, diesel or outboard. Since I spend most of my time cruising the lakes and rivers here the electric is out since the batteries would be really expensive). So now I'm down to replacing the 2stk with a diesel (if I can find one at a reasonable price) or get an out board. My thought with a 4stk OB is to mount it directly onto the rudder. I would rebuild the rudder to accommodate it and reinforce the hinge system (I'm and engineer with access to a machine shop). Could I please ask for some opinions, thanks in advance.
 
Jan 7, 2011
4,727
Oday 322 East Chicago, IN
I don’t think you mean you would attach an outboard to the “rudder”. Tbe rudder has to move back and forth under water to steer the boat.

Maybe you mean mount it on the transom.

A new diesel with sail drive would be an involved replacement I would think. But so is closing up the hole for the existing saildrive.

Greg
 
Nov 6, 2006
9,885
Hunter 34 Mandeville Louisiana
The old dear (powerhead) can be rebuilt; parts are still available through Bombardier .. It is a standard powerhead from a 15 HP outboard engine, Johnson or Evinrude.. may only need new piston rings and some carburetor work.. An inexpensive option, doesn't address the two stroke smoke.. If ya took the powerhead off and took it to a good OMC/Bombardier shop, they could probably do it..
EDIT: Welcome to the group !!
 
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Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Repairing the old powerhead might be the most practical thing to do. But if you do go to an outboard, the 4 stroke is definitely the way to go. You could link the outboard to the rudder with a connecting rod, so that they both turn at the same time. I have seen this done. Swivel joints are used at each end of the connecting rod, so the outboard can be swung up or raised out of the water, without affecting the operation of the rudder. Most sailboats, though, just mount the outboard to the side on the transom to give the rudder room to swing. My old O'Day 23 had a cutout on the side of the transom for the outboard. I had a 4 stroke Yamaha 9.9 mounted there, and I could handle both tillers at the same time. I could handle that boat in reverse like it was on rails.
 
Jan 6, 2019
24
Nash 26 Ile Perrot Yacht Club
Thanks guys, but I want to stay from the 2stroke altogether. My idea is to build the 4stk outboard right onto the rudder. The rudder would turn the same as normal, it would just have the OB attached to it. I've seen this done in large sailboats with electric motors and they are extremely maneuverable. So I'd like to try it with an OB.
 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
Thanks guys, but I want to stay from the 2stroke altogether. My idea is to build the 4stk outboard right onto the rudder. The rudder would turn the same as normal, it would just have the OB attached to it. I've seen this done in large sailboats with electric motors and they are extremely maneuverable. So I'd like to try it with an OB.
I've never seen that done with an outboard and I can't really imagine it working. First problem is that you'll have a huge weight on the side of the rudder, and when the boat heels it's going to want to swing strongly. The other problem is that all the torque of the engine will be trying to turn the rudder when you want to go straight, which seems like it would be a big fight to counter.
 
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Jan 6, 2019
24
Nash 26 Ile Perrot Yacht Club
@
I've never seen that done with an outboard and I can't really imagine it working. First problem is that you'll have a huge weight on the side of the rudder, and when the boat heels it's going to want to swing strongly. The other problem is that all the torque of the engine will be trying to turn the rudder when you want to go straight, which seems like it would be a big fight to counter.
Good points David, I would mount the motor in the center of the rudder with custom brackets and reinforcements for the gudgeons. I would also have to dampen the steering so it wouldn't fight to turn
 
Jan 6, 2019
24
Nash 26 Ile Perrot Yacht Club
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Tom J

.
Sep 30, 2008
2,301
Catalina 310 Quincy, MA
I've never seen that done with an outboard and I can't really imagine it working. First problem is that you'll have a huge weight on the side of the rudder, and when the boat heels it's going to want to swing strongly. The other problem is that all the torque of the engine will be trying to turn the rudder when you want to go straight, which seems like it would be a big fight to counter.
I think Davidasailor is correct. Mounting an outboard on the rudder does not seem practical, but using a connecting rod between the rudder and the outboard would give you the maneuverability you are looking for.
 

Tom J

.
Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Hello all, I'm new here so please go easy on me. I have a Nash 26 with an OMC Zephyr 2cyl, 2 stroke wigh sail drive from the early 80s and I'd like to change it (mainly because it is noisy, smokey and I think it is coming to the end of its life). I had 3 options going in; electric, diesel or outboard. Since I spend most of my time cruising the lakes and rivers here the electric is out since the batteries would be really expensive). So now I'm down to replacing the 2stk with a diesel (if I can find one at a reasonable price) or get an out board. My thought with a 4stk OB is to mount it directly onto the rudder. I would rebuild the rudder to accommodate it and reinforce the hinge system (I'm and engineer with access to a machine shop). Could I please ask for some opinions, thanks in advance.
When you mention electric, and extra batteries, if you consider the Torqeedo outboards, the battery is built into the outboard itself. There are several models available for your size sailboat. It might not be as practical on rivers and lakes as it is on open water, since you wouldn't be sailing as much as you would on the ocean. I think they might even have a sail drive model. Something to think about.
 
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May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
That is pretty interesting. Still, the torqueedo pod they use weighs what, maybe 30 pounds? A whole torqueedo outboard at the same output is 37 lbs. That's a lot less weight to absorb than a 4 stroke outboard, and it's on a bigger rudder than for a 26 foot boat.

I would mount the motor in the center of the rudder with custom brackets and reinforcements for the gudgeons. I would also have to dampen the steering so it wouldn't fight to turn
Yeah, after I posted I thought maybe you could do something like that. Still, the advantage of a tiller steered boat is the feel and connection you get to the water when you're sailing. Adding something to dampen the weight of the outboard is going to spoil that. Also, would you have the outboard off the back of the rudder, or somehow integrate the outboard into the rudder with the outboard close to the transom? The further aft the outboard goes the more torque its weight will have and the more you'll have to counter.
 
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Jan 6, 2019
24
Nash 26 Ile Perrot Yacht Club
I will make some drawings this week and post them to see if you guys may agree on the concept of the rudder mount.
 
Nov 6, 2006
9,885
Hunter 34 Mandeville Louisiana
Another thing to consider would be to build an adapter plate and mount a 4 stroke vert shaft engine in the same location. It would be air cooled so would need a ventilation plan and the issue of the hot exhaust would have to be worked, maybe using the foot mounted water pump to cool it? Still would be gasoline, but wouldn’t smoke and would burn much less fuel. Harbor Freight has one for about $750.
 
Nov 8, 2007
1,523
Hunter 27_75-84 Sandusky Harbor Marina, Ohio
I’m with those who recommend rebuilding the current engine! Another alternative is to sell the boat and buy another!

Why not mount an engine & propellor on the rudder?
- Weight and drive forces on the rudder will eliminate “feel” and put strain on the helmsman/woman.
- The motor, attachment hardware, and control hardware will screw up the aerodynamics of the rudder. Stalling of the rudder is the cause of rounding up which will become more frequent. The rudder will not be as effective while sailing.
- Regardless of how well it works, this solution will lower the resale value of the boat.
- Like any prototype design, implementing your project cost a lot more rework, adjustment, changes, and labor than you plan.

On a totally different thought, this raises another argument against sail drives! As a boat ages, maintenance and replacement of a saildrive system is much more difficult the either an outboard, or standard inboard design. It turns out fiberglass sailboats last far longer than anyone thought. Ours is 41 years old and still performs like new! In our 19 years as owners, we have replaced the shaft, the prop, and the engine at different times, when they reached the end of their useful lives. Each of these actions were straightforward. Although I hired our yard to do them, I could have done them myself. And each of these actions had no impact on the basic design of the boat.
 
Jan 6, 2019
24
Nash 26 Ile Perrot Yacht Club
Here is my idea - I know you'll have to think "out of the box" but it is worth considering.
The first is my current configuration with the sail drive; the second is how I envision the new rudder. The shaft going to the top of the transom is for an emergency tiller, otherwise the steering is with a cable.
(I think you'll have to rotate them 90* left)
 

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Tom J

.
Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Here is my idea - I know you'll have to think "out of the box" but it is worth considering.
The first is my current configuration with the sail drive; the second is how I envision the new rudder. The shaft going to the top of the transom is for an emergency tiller, otherwise the steering is with a cable.
(I think you'll have to rotate them 90* left)
Interesting. Something to consider, though, is the depth of your prop. I had a 9.9 Yamaha long shaft on a swing mount, and even with the motor lowered all the way, the prop would often pop out of the water in rough conditions. It's very hard to make headway when the prop keeps cavitating. You would want your prop somewhere near to the depth of the original sail drive.
 
Jan 5, 2017
2,263
Beneteau First 38 Lyall Harbour Saturna Island
It's very hard to make headway when the prop keeps cavitating. You would want your prop somewhere near to the depth of the original sail drive.
Having had several outboard driven sailboats I agree. They work well in calm conditions but are near useless when the seas kick-up.
 
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Jan 6, 2019
24
Nash 26 Ile Perrot Yacht Club
Good points David, I would mount the motor in the center of the rudder with custom brackets and reinforcements for the gudgeons. I would also have to dampen the steering so it wouldn't fight to turn