Indigo or Martec

[Tar34]

I sail a Tartan 34c. In the Electrical section, I sought advice on upgrading my DC power output, i.e., possibly upgrading the alternator. I currently have a Martec 2 blade 12x7x1 on a direct drive A4. Cruising RPM is less approximately at 1400, maybe less. I am at the point where my Martec needs reconditioning. I could spend the money to recondition the Martec which I think is too much prop for my boat to go with a three blade Indigo. It bothers me that I might give up a performance gain I might have with Martec when sailing although the performance gain while under power with the Indigo intrigues me. New Indigo $325. The Martec has not been evaluated at the factory but I should expect to pay $250 worst case scenario. The money difference is immaterial. The Indigo is elliptical 10DX7P.

http://www.martec-props.com/refurbish.htm

http://www.atomic4.com/propeller.html

[Al Schober]

Please consider the CDI propeller. I've been using one of these on my Tartan 30 for quite a while and am very happy with it.

http://www.sailcdi.com/ppmain.htm

[Tar34]

Please consider the CDI propeller. I've been using one of these on my Tartan 30 for quite a while and am very happy with it.

http://www.sailcdi.com/ppmain.htm

I'd be happy to consider the CDI. I would like to hear more from actual users.

[67c&ccorv]

I have the Indigo on my C&C Corvette...very similar to your Tartan.

I haven't regretted putting that prop on my vessel for one minute!

[romantic comedy]

I have the Indigo on the tartan 34 for 12 years now. It has worked great. I cruise at 6 knots and 2000 rpm. The boat backs to port big time. Today, while docking I had a blast. That is no different then the 12 X 6 I had before.

Get the prop. Tom designed it on his T 34.

[Loki9]

I had a Martec on my Pearson 30. I thought it worked great and after all, I spent 99% of the time sailing with the motor off. Why would I want to drag around a fixed blade prop?

[joe_db]

If you live someplace where you can spend 99% of your time under sail, then I would not bother with a fixed prop either.
I have the Indigo 3 blade and am very happy with it.

I had a Martec on my Pearson 30. I thought it worked great and after all, I spent 99% of the time sailing with the motor off. Why would I want to drag around a fixed blade prop?

[Dave Neptune]

Only 1400????

Tar34, I have been a big supporter of the Indigo for some time now! I also have had some experience with the "plastic" props both CDI and Com;Props. They all work fine. If I was sailing in waters with lots of hard debris in the water I would go plastic if not it's bronze for me.

I don't think you are ready for a prop change until you get your RPM's up a bit or find out why they are so low. With 7 inches of pitch on the Martec it should spin much faster than 1400. What is your WOT RPM range? I would wait for what Martec reports they find as far as pitch is concerned. As if it is indeed 7" and you only get 1400 something is either wrong with the tach or the "tune" of the engine or the prop is fouled and/or out of wack.

I had a friend recently do the Indigo change over from a Martec that was an 8" pitch, he gained about 200 RPM's at cruise and 300 on the top end. BTW he is not a racer and did not notice if the boat was slower sailing. He did like the additional control in reverse though!

Dave Neptune

[Tar34]

Tar34, I have been a big supporter of the Indigo for some time now! I also have had some experience with the "plastic" props both CDI and Com;Props. They all work fine. If I was sailing in waters with lots of hard debris in the water I would go plastic if not it's bronze for me.

I don't think you are ready for a prop change until you get your RPM's up a bit or find out why they are so low. With 7 inches of pitch on the Martec it should spin much faster than 1400. What is your WOT RPM range? I would wait for what Martec reports they find as far as pitch is concerned. As if it is indeed 7" and you only get 1400 something is either wrong with the tach or the "tune" of the engine or the prop is fouled and/or out of wack.

I had a friend recently do the Indigo change over from a Martec that was an 8" pitch, he gained about 200 RPM's at cruise and 300 on the top end. BTW he is not a racer and did not notice if the boat was slower sailing. He did like the additional control in reverse though!

Dave Neptune

Hi Dave! Others have commented about the 12 x 7 prop being a little too much.
I have the option of having the Martec recut, say to 11 x 7. My engine is tuned, i.e new carb, points, distributer rotation for max rpms ect. I have never taken a compression test, but her rpms are in line in what other have reported. Prop freely rotates if I let it under sail. It will be interesting to hear from Martec.

[Dave Neptune]

Seems low?

Tar34, if all is well with the tune and the prop numbers come back good from Martec you may want to check your tach against another if you can.

Is your 1400 at WOT or easy cruise? If it is your cruise RPM what is WOT RPM?

Dave Neptune

[Tar34]

At WOT maybe 1800 though at this point I'm unsure. Boat is on the hard for the winter. I think the engine is definitely laboring above 1400. From a boat speed perspective @1400 in flat conditions I can achieve 5.5 its., maybe a little more. Obviously I probably I could have analyzed the system a little deeper than I have. The boat is out of the water the prop is off and the prop needs to be refurbished. Perhaps I'll just keep the same dimensions for another year and try to work out any bugs this next season.

[sastanley]

Tar 34...I am with Dave on this one...1,400 seems really low. Even 1,800 seems low for WOT to me.

What is the displacement and LWL of a T-34?

My C-30 originally had a 12 x 7 (fixed) would still get over 2,000 RPM at WOT, with 10,200 lbs and 25'0" LWL. I am hoping a similar length to displacement ratio between the two boats will help with my theory of similar performance, but I am not a naval architect.

I like the Indigo I have now, and it seems to perform as advertised. But if I were buying another prop, I might also seriously consider a CDI. I am just cruising on her these days, however, even as a performance cruiser, I still think about the 3-blade I am dragging around all the time.

[romantic comedy]

T 34 has a 25 foot LWL, and 12000 pounds displacement.

I get 2200 rpm wot with the indigo, on my t 34.

[sastanley]

Thanks for that data RC, that seems to make sense..with everything clean, I can get about 2,250 with my Indigo at WOT. I was 2,100-ish WOT with the 12 x 7...however, my cruising RPM is 2 or 3 hundred RPM higher with the Indigo which is where the motor is most of the time..WOT is extreme conditions, and I don't like running her there unless needed. I cruise 1,800-1,900 now, when before it was 1,500-ish RPM for the same boatspeed. I think the motor is much happier cruising at 1,850.