Propeller Selection

[sastanley]

Dave, I am very interested in this thread.

I am performance oriented, but I realize I own a cruising boat...(Catalina 30, no offset, but similar strut/prop/shaft configuration.) If I can get the HP/RPM numbers up a little bit and get the motor running more efficiently, all the better!

I am worried about sailing performance, but I am also concerned about improved motoring performance. Slamming into waves/wind and having no power just plain sucks.

With a 2-blade prop, I can always hide it vertically, although when cruising I rarely worry about it, and just stick it in reverse to stop the prop from spinning. On a long passage, I'd likely check it.

Please continue feedback on your observations. Your old prop looks just like mine, and if the Indigo (at only 9.6% surface area increase) seems worth it, great! Thanks.

[Dave O]

Sastanley:

I'll let you know how things work out c/with tach readings. I don't have one now but plan to install a tach over the next month (see another thread re. ease of installing a tach) so perhaps that will help.

So far and to date, much better performance in reverse around the dock and a smoother ride in forward when out of the dock cruising. I understand that's very subjective so performance with a tach will help.

One point I have noticed ... reverse thrust is great but with that increase comes associated steering problems.

Reverse thrust can be so strong that when I put the engine in forward after backing out of the slip, the bow can continue to swing strongly and beyond what I am accustomed to with the 2 blade prop. So instead of creeping out of the dock I tend to zoom out, and the bow passes beyond the 90 degree turning point and can get as far as 180 degrees. This is a bit hard to visualize, but it certainly causes some anxiety for me and probably my neighbours in other slips. It's just an issue of becoming more experienced with the new handling features of the boat in tight quarters.
Dave

[sastanley]

prop-walk

Hi Dave, Thanks..I gotcha on the prop walk. My step-father owns a Tartan 3000 with a Martec folding prop. Talk about prop-walk! - In his case it works well and pulls him to port in reverse, and into his slip nicely, but you have to anticipate it. New friends on the boat, or people on the dock always wonder how in heck we'll get the boat to turn 90 degrees in reverse in one boat length when they see him set up for pulling into his slip

In my experience, the key seems to be to get going fast then throttle back & coast so the rudder will overtake the prop wash. I don't have much trouble with the Catalina yet, but not much bite in reverse either with that old 2-blade.