Worth upgrading my prop?

[Chris Simenstad]

In anticipation for doing some summer cruising, I am thinking of upgrading my 2 bladed 12"x6" prop to get more RPMs and better speed under motor. I see that the Indigo propellor is 10" X 7.4". Will more pitch mean less RPMs? How should I figure out if this is a worthwhile upgrade?

[sastanley]

indigo

Chris,
There is lots of discussion about the Indigo props floating around on the Internet. From what I have read, most people seem satisfied with the performance the Indigo provides.

I have the standard 2-blade 'whatever-came-with-a-Catalina30' prop, and have considered either the Indigo, a folding Martec (12 x 6) to improve sailing performance, or the composite CDI prop, which flattens out and eases pitch even more at higher RPMs. Interesting concept.

[Dave Neptune]

Prop

Chris, I have had an ol'e E-35 MkII for twenty five years now and have tried four different props in 6/7 configurations. The props I tried were all two blade and one martec. After trying to modify pitch and diameter for gains I heard of the Indigo prop. I installed it and have left it alone and am quite satisfied with it's overall performance. I didn't really pick up any speed however it did reduce the load on the engine and allows operation at around the 2,000 rpm mark for cruising at hull-speed. I also have a bit of power left available for nasty conditions as I can reach 2400 rpm's, this is something I didn't have before. My real reason for sticking with it is now my boat actually is capable of backing up with a good bit of control, something it would not do before. The other really noticeable gains are how quiet the prop is, how little "prop-walk" there is, how little prop-wobble is felt through the rudder and how little drag it produces for a three blade. When I replaced the 12x8" with the Indigo I noticed little or no differance sailing in light air, if anything it is a little faster!!! Most of my boating is done towing a 10" Drake lapstrake fiberglass dinghy I converted to a rowing one. I am amazed that I barely notice the dinghy any more as well.

David

[sastanley]

less drag than a two blade under sail?

David,
Do you really think there is minimal/no loss in sailing performance?? I am not doubting you, it would be a pleasant surprise!

[Dave Neptune]

Drag

sastanly, yeah that's correct!!! Indigo claims less drag than a std. sailor prop of 12' diameter and I must say I deffinately did not slow down in light air, in fact I did very well in the Ashbridge at Catalina last year. The race was about 12 miles and the first 10 took 4 1/2 hours and I led the way until the air filled in and a Pugh 47 & a Bene' First 38 finally got by. My boat isn't all that fast however I am compettitive in the really light stuff and if anything I was a little faster the last few years with the Indigo! The4 only down side of the Indigo is when doing a "dead calm harbor cruise" at speeds slower than cruising it requires a few more rpm to achieve what I could get with the 2 blades with more pitch.
What are you thinking of putting it on? It seems to need a good exposure to the water flow and does not like being behind deadwood or thick enclosures from the responces I have seen on line and on this site. The Indigo blades are surprisingly narrow to what I have worked with in the past, not much drag!

David

[sastanley]

Well...I may put it on my Catalina 30, if I can actually get the thing running this spring and enjoy some sailing. I had been leaning toward a Martec folding, to minimize drag, but I don't know if it would do anything to improve the motoring capability over a standard sailor prop, which I think is what I have now. The shorter blades would help with hull slap too, as even the 12" prop is only about 1.5" from the hull if I recall, and reverse is dismal.

This would be a "nice to have" right now...I've dumped so much money in the boat on other things this would be an 'upgrade' in a season or two. I am pleased to hear the drag issue from someone re: the Indigo prop..

Thanks for the info.

[Dave Neptune]

Prop

Shawn, the Martec will give you less sailing drag as well as poor reverse performance while having marginal performance forward ---AND---less noise through the hull. My hull is insulated and I still noticed how much quieter it is and I have pretty good prop-to-hull clearance. I have made many modifications to my A-4 that have improved the overall performance and the Indigo was one of them and the most recent.

David
Volador 1970 E35 MkII w/original A-4

[Chris Simenstad]

Dave, thanks for the feedback. I think I'm going to give it a spin (my boat is a 1975 ericson 32) and see how it goes. I don't race but am looking for more punch and maybe speed.

--Chris

[gfatula]

I am looking at the Indigo prop too, for my Islander 28. One consideration I have is the "activity" of the harbor where I haul out. I contacted Indigo and asked about the sacrificial quality of the prop in a "hot" harbor and was told it could reduce the life of the prop to as little as three years without a zinc. I spend a little time each year in Northeast Harbor, Maine and can loose a zinc in less than a month because of all the electrical activity in and around that harbor.