Prop Shaft - where to start and end....

[ndutton]

Romantic Comedy's information is exactly what I was talking about. If your interest in an Indigo prop was to allay reverse prop walk (as indirectly implied by the criticism of the 12x7 2 blade characteristic in post #12), it sounds like you'll be disappointed.

If your interest in the Indigo was broader, particularly wanting to operate in a higher RPM range approaching what the reduction gear guys enjoy and now with the understanding that reverse prop walk is a way of life, then the Indigo may be worth the investment to you. Romantic Comedy feels it is but prop walk may have been low on his list of expected improvements.

Said again, assess your needs and expectations and rely on the experiences of others available on this forum before the final decision.

[tenders]

I have the Indigo on a 3/4" shaft and like it well enough. Its main benefit is that its smaller size lets the engine run closer to its sweet spot in power output. It is nominally better in reverse, because when you goose the engine it bites a little sooner, but no sailboat and no prop is good in reverse. Prop walk at low hull speed is a fact of fluid dynamics, you can either kvetch about it endlessly or use it to your advantage (because it happens in forward too).

If I were you I'd stick with the 3/4" and go with the Indigo.

[BadaBing]

My Tartan 30 has the engine mounter at the center of the keel forward and aft but on the port side of the keel. To the extent that my waterpump is almost.over the line of keel bolts.

My shaft log.and shaft exit the hull at the rear center line of the keel. Therefore my shaft and prop are pointing to starboard. Backing to St a rboard is just a fact of life with a T30

To compensate I ,and I under s tamd othrrs, when backing, engage reverse just enlugh to cause movement then shift back to neutral. by shifting in and oit of reverse I am able to bacm down in a pretty straight line. well as straight as any sailoat can.
However I go oit of my way to avoid backing into slips.in winfdy , crowded or current affected waterways.

[Dave Neptune]

bradh, I would suggest sticking with the 3/4" shaft. It is plenty big enough to handle the A-4 and will be easier to replace. In many of the E-35mkII's with the engine under the setee alignment is a problem. I have a cored hull and actually have a "mis-alignment" that can not be adjusted out. I have heard of more than a few of this model using the long 3/4" shaft as sort of a "flex shaft" and they recommend not going bigger for this fact. "Hanley" you can avoid twitching here if you can. I have run my Volador for over 35 years now with this alignment issue and no problems. I have also seen two of these E-35's with the port rear mount left out to allow for alignment to be done properly.

I did change out my log once in the 35 years as it was wearing against one side, duh. I pulled the shaft, straightened it and installed the new packing on a fresh spot of the shaft with a longer piece of hose. That's been working for at least 10 years now and no leaks or issues running with the Indigo. I have many years experience using the Indigo and found it to be a vast improvement over the other 5 props I had tried!!!!!

Dave Neptune

[JOHN COOKSON]

edit: BTW Brad, next time you're backing give her a burst of thrust to just get her moving then immediately shift to neutral and coast backwards. You'll have much more control.

When you use the initial burst of power in reverse have the rudder amid ship. It's temping to think "if the boat walks to port I'll put the rudder to port, make a resistance on that side, and the boat will back straighter." It won't work. Water needs to be flowing past the rudder before it has any turning action. This is the advantage of the initial burst of power. It makes it so you can steer.

TRUE GRIT

[roadnsky]

Racers would be apoplectic over a three bladed prop unless it enhanced their handicap rating greater than the sailing performance hit.

Extra credit for the excellent use of apoplectic...

[ndutton]

Extra credit for the excellent use of apoplectic...

It's racers. They're apoplectic most of the time anyway . . .

[romantic comedy]

Neil has it right.

Props on sailboats are going to be a compromise.

How does a T 30 back to starboard?

The Tartan 34 has the engine in the main cabin. The prop is way forward of the rudder. The prop is almost 1/3 of the boat length forward.

[sastanley]

Whether I am driving my Stepdad's Tartan 3000 (A Tartan 30 hull with spade rudder, better keel and an 11HP M-15 diesel with Martec folding prop) or my C-30 with the OEM 12x7 2-blade, or my C-30 with the Indigo..the key is always as John Cookson noted above. You have GOT to get the boat moving backwards to get flow over the rudder, which is now flowing backwards of its designed NACA foil shape (keel included!) if you expect any control in reverse. With the reversing gear on an A-4, prop speed is reduced from the typical 1:1 direct drive for a given RPM, so it is imperative to get the RPM's UP and get going, then you can reduce RPM & ease the lever into neutral, etc, and let the rudder work.

I've found a negligible difference in my boat's reverse handling with the standard 12x7 2-blade, or the 10x7.4 Indigo.

Neil, I do notice a bit of difference in sailing performance in light air since I am a racer at heart, but it is not enough to offset the benefits of running at a higher RPM under power (the sweet spot) in the typically light air Chesapeake, where we sometimes have to motor 25-30 NM to get to our next anchorage.

[ndutton]

Shawn,
Have you done any emergency stops with the Indigo?

[sastanley]

Neil, I have to think about that. The physical dimensions of the Indigo prop do indicate it may not be as efficient trying to get max thrust in reverse unexpectedly, but I can't say it has been an issue with my every day navigating. I remember one emergency stop in a tight basin, but I think it might have been pre-Indigo.

However, I also try not to put myself in the position that I need an emergency stop. Situational awareness and all that.

Once I de-winterize, and get the prop clean, I'll do one this season and report back.

[The Garbone]

Since I have only had an Indigo on our C30 I have no reference but that it is a is not even close to as responsive in reverse than a 27 with an outboard.

I approach returning to the slip much like landing a plane without a wave off. Creep in slow enough to grab the stern line to use as a spring,