#1
IP: 172.250.158.136
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Indigo Vs Martec
So last week I had the boat hauled out, bottom paint and new cutlas bearing and also pulled my Indigo prop and put on a brand new 12x6 Martec folding prop.
WOW WOW WOW! I gained 1 whole knot. I am not sure how much of that was bottom paint or the prop. Indigo: WOT 2300rpm 5.5kts Cruise 2000rpm 5.2kts Martec: WOT: 2100rpm 6.5kts Cruise 1900rpm 6.2kts Low cruise 1500rpm 5.5kts Did a few back up and emegency stop drills. Going 5kts went to idle shifted in reverse then 2700rpm. Came to a stop in about two boat lengthens. Prop walk was definitely more noticeable than on the indigo but only at very low speed. No issue once boat was moving. After reversing about 100 feet at about 3kts I put it in forward and had noticeable prop walk the opposite direction it turned the boat counter clockwise almost 90 degrease. That was a first for me. And possibly could have been agrivated by my rudder input. When putting it in forward I noticed the aft end immediately started swinging right and so I entered right rudder but I think I was still moving aft at this point and aggravated the problem until I started moving forward. I have not backed out of a slip yet so we will see next time how that goes. One other observation was left turning tendency of the helm while at cruise. With the indigo if I let go of the wheel it would eventually make a gradual left turn in about a min or so but I could go down stairs and grab a drink out of the cooler and be back at the helm before my heading changed drastically. With the martec it takes less than 10 seconds for that left turn to start and seems to get that left turn going tighter and tighter in just a few seconds. I pretty much had to hold some light pressure on the wheel the whole time. As a flight instructor I said "right rudder" about 10,000 times, it felt just like that. Last edited by Flyingmike; 03-15-2017 at 01:12 PM. |
#2
IP: 206.125.176.3
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That is interesting data...I wonder if a 12 x 5 Martec would get the RPM's back up near the Indigo for a given boat speed.
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#3
IP: 137.200.32.6
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Having gone Martec > Indigo, I would be more than amazed if the Martec is faster with the same bottom.
I usually am at least 1 knot faster going home from the yard then going to the yard Now under sail.............the folding prop will be best of course. |
#4
IP: 172.250.158.136
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I was definitely shocked with the increase in speed, and I am sure 90% of that is bottom paint. When I called Martec I asked for a 12x7 1" shaft and he asked me "where I got that prop size from." I said "12x7 is what the boat originally came with" and he immediately asked "is this for an Atomic 4" i said "yes" and was also a little shocked with how little information I gave him he already knew what kind of engine I was running. He then recommended a 12x6, said with there testing they feel the A4 does better with a 12x6, and so I went with his recommendation since he obviously knew his stuff. Definitely glad I didn't insist on a 12x7 and now wondering if a 12x5 wouldn't have been even better. But at WOT I am getting pretty close to haul speed so I don't know that a 12x5 would have helped that much more. Time will tell and more testing is required. Also after further inspection of my indigo it appears 1 of the blades is missing the tip where it curves up, I never had any vibration issues though but don't know how that affected thrust.
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#5
IP: 148.74.164.249
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I was more surprised at your performance in reverse. My Martec folder is horrible in reverse. Some recommend going in forward before shifting to reverse to make certain the prop actually opens, but reverse performance has always been somewhat poor.
Curious, did you have much growth on the bottom and/or prop before you switched to the Martec? |
#6
IP: 172.250.158.136
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#7
IP: 137.200.32.54
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This was why I gave my Martec away. I had a 13x7 fixed prop and then the Indigo. The Martec would sort-of kind-of maybe go in reverse and maybe not.
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#8
IP: 148.74.164.249
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Yup - that describes it. I'm on a mooring and frankly (fortunately) don't rely too heavily on powerful reverse.
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#9
IP: 172.250.158.136
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13x7, what was your WOT? It must have been lugging the engine something fierce!
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#10
IP: 97.93.89.70
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Numbers
Flying Mike, when you gathered those numbers for comparison were they the same conditions? Was the bottom fresh and just painted when you tested with the Indigo?
I too did some testing many years ago with a fixed prop, a Martec 12X8, and the Indigo. I did all three the same day on the "hull in the same condition" and the engine in good tune. My results were much different and I stuck with the Indigo for the power of additional RPM and better control in and out of the slip. I also found that with a 3 blade rating and the tiny Indigo to be a slight advantage. I actually had less drag than with the fixed 2 blade due to the area of the prop. Did not do any drag testing with the Martec though. Be carefull when gathering numbers that can be drastically influenced by a dirty vs clean hull. Dave Neptune |
The Following User Says Thank You to Dave Neptune For This Useful Post: | ||
sastanley (03-16-2017) |
#11
IP: 75.104.65.4
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#12
IP: 71.179.247.252
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This isn't helping me. I had planned on buying an Indigo and now you're forcing me back to thinking and deciding.
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#13
IP: 97.93.89.70
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It's chooice for application
Mike, I did a bit of testing myself and one thing I found with the Indigo is that it is very sensitive to any crustations or growth. On my 35 footer at 2300 RPM's I would get 6.4 in calm flat water and 5.6~5.9 at sea.
One thing for sure was that the Indigo had a little less drag than my 12 X 2 blade and the rating for a three blade was an advantage in rating. The Martec will indeed have less drag but how does that rating work for your boat~just something to consider. Sedmore, you need to be sure of what it is you want from the prop and your type of sailing situations in choosing a prop. The most important thing is getting as many RPM's out of a "direct drive" as you can to make more power and relieve bearing loads for better lubrication. Dave Neptune |
#14
IP: 137.103.82.194
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The idea that a folding Martec is better than an Indigo *under power* is a very unique one and certainly not common.
I have got 2 or 3 people to buy Indigo's and they all were very impressed with the increase in performance. I surely was happy with mine and the reduction in noise from having greater tip clearance is another bonus. One thing though - Indigos are SMALL 3 blade props. They degrade quite quickly when foul, so I can well see a dirty bottom and dirty prop going to the yard being slower than a clean bottom and clean prop coming home. |
The Following 2 Users Say Thank You to joe_db For This Useful Post: | ||
Dave Neptune (03-18-2017), sastanley (03-18-2017) |
#15
IP: 24.152.132.65
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The only reason I can think of for a Martec is racing and even then it merits careful consideration. Compare real sailing performance improvement of the Martec to the handicap rating bump of a fixed prop. You may be better off taking the handicap for a lesser sacrifice in performance.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
The Following User Says Thank You to ndutton For This Useful Post: | ||
Dave Neptune (03-18-2017) |
#16
IP: 70.214.101.195
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I'll make you a great deal on my Indigo!!
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#17
IP: 97.93.89.70
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sdemore, I'd take up the offer if the parameters of "your use" is not absolute sailing performance but overall performance to your boating needs.
Note, I did win a few races and placed better after the rating change for the 3 blade from the 2 blade. Dave Neptune |
#18
IP: 24.152.132.65
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At the factories I remember widening the strut web with structural filler for a handicap benefit. Seemed crazy to me at the time.
Speaking of handicap rating loopholes, 40 years ago naval architects designed new race boats every other year when the I.O.R. rules changed. An example is the extreme tumble home of hard core racers of the mid 1970's, kind of a ridiculous look for a yacht. Beam for the I.O.R. formula was measured at the deck so the bulbous hull topsides equated to a much greater physical waterline length and therefore greater theoretical hull speed when the boat was heeled hard over without taking a handicap rating hit. Here's a picture of the Yankee One Ton racer designed by Sparkman and Stevens showing the trend. The hull molds were later purchased out of bankruptcy by Catalina, a different trunk cabin deck was designed and the Catalina 38 was born.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#19
IP: 71.178.92.247
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Neil..interesting history. The Catalina 38 history is really fun to learn. I had one very nearby for a lot of years growing up when I was racing on a J/22.
Those IOR rules definitely created some distorted boats! A lot of them went upwind like a b!tch, but downwind..not so good!
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#20
IP: 24.152.132.65
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Which is where we are now with ULDB's, pure downwind sleds.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#21
IP: 71.179.247.252
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I'm not into racing or super performance, just want to learn to sail. With that in mind, what kind of condition is it in and what would you take for it? If you want to go offline, sdemore@computer.org
Steve |
#22
IP: 172.250.158.136
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Took the boat out sailing yesterday. Backing out of the slip was pretty messy!! I bumped into the dock behind me. And had to hold myself off another boat and bumped into a 3rd boat. Nothing damaged but my ego. It was a pretty ugly show!!! Its pretty much night and day difference from the Indigo. Now sailing was amazing!!! Since I was single handed and had a steady 10mph wind I just used the Genoa on my roller, no main. Got the boat up to 6kts on a beam reach, about 5kts on a broad reach. I don't think I ever saw anything above 5kts sailing on just the Genoa so between the hull paint and prop I easily picked up 1kt. Returning to the slip was flawless, turning into the slip put it into reverse throttled up to about 2000rpm and the boat came to a very nice stop perfectly in the slip.
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