Disconnecting Engine Linkage

[Night Sailor]

This discussion would be a lot more meaningful if people who favor having the motor in the water would state if the prop is free to spin or is still locked in gear.

I'm going to try it both ways my next sail over a measured course and see if it makes any difference in speed (per GPS) on any point of sail. Wind, wave and traffic conditions have always dictated my choice of motor position, not speed differentials. If there is a measurable difference you will hear from me again.

I always leave the motor connected to the steering. I don't find it makes any difference in steering, up or down. Could be my boat has just the right amount of friction in the cables to negate any motor pull or flop. (Merc 50 Classic). It's been that way since new. (1998)

[Scott]

Chip said

I don't doubt that Scott saw 1 to 1 1/2 knots variation, I only argue that attibuting such to lowering or raising the motor is a giant leap of faith; a triumph of hope over reality.

Not quite, I remember a difference not how much, I seem to remember the thread consensus at 1-1 1/2 knots.

I do however experience a significant loss of speed if I raise my motor while motoring.

[They Theirs]

Moe

Im not doubting your results, and can only say: Those who have enough experience and love sailing develop a feel for boat speed when sailing. I cannot tell the exact speed in knots of the wind, or the exact loss when dragging the engine at any instant in time, but I can feel the difference when dragging kelp, and for sure when Ive forgotten to tilt the engine up. (With the engine steering disconnected, of coarse)
I cant say enough for the GPS for all its amazing information, but the best measure for gain or loss of relative boat speed is the through hull knot meter. (I dont have one) The GPS is not instantaneous, and gives more of an average speed over a measured amount of time lapsed between correlating a somewhat degraded transmissions. The knot meter will show the instantaneous loss of speed even in a variable wind, with or against a current. I would like to think your test was on a beam reach with a good turn of speed on the knot meter, you drop the engine and I guarantee that reading is going to drop.

Im glad you mentioned the small footprint of the Suzuki. With all the talk of Big Foot and Large Propeller sizes ranging 14, 15, and probably larger. One of the benefits of the Suzuki (Combined with the many discussed before) is the Small Footprint. The large prop, Big Footprint may marginally enhance low speed acceleration, and maybe give a small hole shot for minimal benefit, but when it comes to delivering the best speed and economy, in the same hp range, the smaller Suzuki 12 wins. Less Drag when you forget, or desire to leave the engine down.

Good one Scott!

[Don T]

Hello:
I notice a big difference in light airs. Having the motor up improves speed. Also, on my boat 90% of the steering force is in the cable (95 w/original cable) always has been. That's why I leave the motor attached to the steering and raise it. When we have trouble with steering loads is when the rudders are not in the correct position or with a following sea when speed gets excessive.

[DLT]

My "barely noticable" opinion is based on a free spinning 14" prop. I imagine that a locked prop would have significantly more drag. But, I always cut my engine, when in neutral, so I just leave it there and let the water spin the prop when I'm sailing.

My "barely noticable" opinion is also based on a clearly non-race mentality. I'm quite fat, dumb, and happy sacrificing those tenths of a knot that I attribute to motor drag for the convience of keeping the motor in the water... I've started it frequently enough with it out of the water, thank you very much. I also don't have to worry about disconnecting it from the steering... So, leaving it in the water gives me two less things to worry about...

[They Theirs]

DLT

I hardly think anyone here finds your posts Barely Noticeable. You are after all a well seasoned and respected Captain .

Considerations On Choosing A Sailboat Propeller
Choosing a Sailboat Propeller

Three Blade Fixed Propellers
For some propellers it is the equivalent of dragging a hand through the water. Most sailboat builders use, as the standard fare, heavens forbid, a powerboat propeller and the drag can be much worse, like dragging a bucket.

They also create a lot of drag under sail, whether locked or spinning free,
What a Drag
David Zielke wrote:

The question of if your prop produces more drag when spinning vs locked
depends on the projected surface area of the blades relative to the circle
which they occupy. If the projected surface area is below some value (I
can't remember the number but something like 40% sticks to mind) then lock
the blade. In this case the turbulence generated by the rotating blades
creates more drag than the prop just sitting there. On the other hand,
when using a big 3 blade prop with large blades you generate less drag
by letting it spin.
Now, one point. If you suck power off the shaft while it is spinning that
is certianly going to generate more drag than if the blade is allowed to
free wheel. The locked blade is a special case and applies because the
system is not rotating.
This is why two bladed props almost always are less drag when locked and
with the exception of the narrow blade three blade props, three blade props
will generate less drag when spinning.
Also if you have a two blade prop which is right behind the keel, lock it
vertically so that the entire prop is alread in the turbulent wash comming
off the keel and the extra turbulence of going around the prop is not very
large.
David Zielke

[Catigale]

Also if you have a two blade prop which is right behind the keel, lock it
vertically so that the entire prop is alread in the turbulent wash comming
off the keel and the extra turbulence of going around the prop is not very
large.

Look off the back of a Mac (at least an ) under sail and you will see that the above paragraph applies perfectly - ergo little advantage

[baldbaby2000]

Try it both ways, take notes as to the conditions, and let us know. Whatever the result I say disconnect it and raise it. There's less wear on you're steering system and you can still motor and steer with the rudders. Probably the best reason for not leaving it down is that it gives all the Mac bashers another reason to say we don't know what we're doing!

[Catigale]

I have tried this on a broad reach on the Hudson, making about 4 kts under main and genny, and was unable to see a difference on the GPS with a resolution of 0.1 mph.

I was doing this to prove to the Admiral that we should lift the motor to get better sailing performance rather than leave it down for emergencies.

Like most arguments with the Admiral, the outcome is self evident.

YMMV

[Frank C]

[ ... (We were surprised to learn that the extra point for securing the outboard was a Blue Water Yachts innovation, and Todd and Cheryl sell the parts for this system to MacGregor dealers and owners throughout North America.)

Me too (surprised to learn that "magic" extra point for securing the outboard was a Blue Water Yachts innovation).

I received my 26X as it was delivered, on trailer, directly from the factory in Costa Mesa. The "threaded stud extension" upward from the starboard rudder pivot ... that was clearly installed in the Costa Mesa factory. It's about as innovative as any other ten-cent hardware change. As for the stainless threaded rod to connect the outboard to the rudders ... innovation? .... pulleeesze! How else could one connect it?

As for the debate to disconnect the motor or not, I choose not. Even though it weighs 350 lbs, I usually raise my Suzuki DF-60 (14" prop) when sailing and find it does not flop within the steering system, even when heeled at 30+ degrees. Can't explain why, it just doesn't, so I see no reason to leave it in the water.

• * CoG? ... agree w/ Chip!
  * And prop drag? ... it surely can't help, even when in neutral!
  * And in very heavy air? .... I may leave the motor down for quickest emergency access.

If wind is that strong, the motor's not appreciably slowing the boat. And as mentioned above, I always shift into neutral anyway before stopping the motor - else you need to shift anyhow before restarting it.

[Sloop John B]

Hey, what's the matter with you guys. Get a little plastic windmill and stick it out the window on your way home from work. Whirrr.

Not too bad. Now grasp the plastic blades and hold it out the window. Ouch (my elbow)!

Now get everything the hull inside and roll up the window.

Motor has the same rudder effect as a fat shovel.

So, if you're racing some dude in an M with a bottle of Seagrams VO at stake, get your motor out of the water, and as you approach the finish line, creep up to the bulkhead and then race back to the transom. Yes, let Newton's law propel you to victory and a good swig.

[delevi]

I noticed a to knot gain when titled up and disconnected with a lighter helm. If I remember correctly, this was in moderate winds. I did experience more stability in rougher seas with the engine down. Im not sure about weather helm and difference in heel, but it makes sense that with the bulk of the engine weight higher and a 20-30 degree heel, the added pressure to leeward can be more dramatic with a 230 lb engine 1 foot aloft. This would probably add to the heel and contribute to weather helm. Does anyone know if the BWY linkage/disconnect system can be used on an Etec 50?

[They Theirs]

Im joining Sloop!

[aya16]

Seems some of the same people that say the Mac isnt like a real sailboat are the ones sailing with the engine down...


Ok lets stop kidding ourselves here, some one might be new to the Mac and read this and want to really know the right answer. The Mac will act like, sail like and steer just like a real sailboat with the engine disconected and up.
The engine when up and disconected will flop like a giant weight on the down side. if not secured. I sail alot and always trim up and disconect the engine as soon as the sails go up. I dont do this because I heard it is better. I do it because it is better. Seat of the pants will tell you this is true
The boat sails with alot less strain this way.

[Dan B]

I have watched my GPS many, many times to see if there is any speed gain from raising the motor. 95% of the time it didn't matter. A very few times I noticed a .1 knot increase.