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Tartan 37 Owner's Forum - Ride the wind, but look good doing it!
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 Post subject: Re: beta
PostPosted: 06 Dec 2020 21:58 
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Joined: 29 Dec 2006 09:38
Posts: 656
I am a huge fan of an externally adjustable pitch of the prop, no matter what you buy. Getting your prop pitch in sync with your RPM of the engine could be really expensive if you have to take the prop to a prop shop to adjust it a few times. I have had a three blade feathering Autostream (Austrailian made, sold and serviced by Martec). I put a 17" on my Tartan. Feathering gave me a half knot of speed and the adjustable is something I have tweaked a bit when things change. During the years I was out cruising longer distances (California to Maine via Panama) and heavier I moved it a bit and also I have been able to fine tune it to my Yanmar replacement engine which has a different torque curve than the old W50. I have been able to adjust it by free diving. Sailing Soulianis put one their boat and I think have quite a few miles and experience so they might comment. I have 15 years and at least 15K miles on mine with no problem. I like that it is stainless and stronger than the Maxprops of bronze. I picked up a 1" line in Miami harbor that stopped the engine, sheared my coupling and popped out my cutless bearing but did nothing to the prop. I have seen 2 situations in my cruising years where Maxprop folks lost a blade from striking something. I think a 17" could be big for some shafts. Mine fits but you need an inch and a half between the tips and the hull to ensure you do not get cavitation and noise.

Ray Durkee
#373


 
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 Post subject: Re: beta
PostPosted: 20 Dec 2020 13:40 
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Skipper

Joined: 14 Jul 2012 20:36
Posts: 495
Location: Norfolk, Va
Flexofold had a good thought about the T37. With the hull not being flat above the prop, the tip clearance isn't going to be a problem with the 17".

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Hull #208, Puff Card
Southern Chesapeake Bay


 
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 Post subject: Re: beta
PostPosted: 23 Dec 2020 00:59 
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Skipper

Joined: 29 Dec 2006 09:38
Posts: 656
I am the advocate for externally adjustable pitch on some kind of feathering prop. Otherwise, it is going to be something like a crap shoot to get the exact pitch for the weight, hull design, hp, WOT RPM and torque of your engine. Most production boat seem over propped in my experience as a delivery guy. But repitching a fixed propeller is not cheap--and you have to remove it, test it and put it back on. There is a book by David Gerr called "The Propeller Handbook" that is very good on all this if you can find it someplace. I accidentally gave my copy away. You should be able to hit max hull speed at the max rpm (No it will not hurt your engine to be run at max rpm--it is part of the break in on Yanmars and some other marine diesels to set the rings and is recommended for brief periods as a maintenance procedure in the manual.) Then cruise at 80% of max rpm. Diesels do not like being lugged or run cold. I don't remember what I paid for my Autostream 20 years ago (Aussie product sold and serviced by Martec) but I have had it on two engines in my boat. Had to repitch it (about a 10 minute free dive job because it just takes a wrench and screwdriver on the outside of the prop.) to fit the different torques of the two engines. I am not sure how many of these feathering, adjustable props that a talented diver could adjust in the water but there must be more options that just the Autostream. But after at least 20K miles, I would buy it again. I picked up a 1" poly line in Miami harbor and it sheared my coupling and ripped out my cutless bearing--no damage to the prop. Up here Maine I pick up a couple pots every year (I have a cutter and you need one too if you come here) and have never had damage. When I was out cruising the guys with bronze Maxprops seemed to have issues with stuff they picked up and hit. We stopped using bronze shafts long ago. I am thinking they just continue with bronze because it is easier to repitch on the machines. Stainless is going to need to be externally adjustable flat blade. I would be interested if there are other externally adjustable props out there.
FWIW.
Ray


 
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 Post subject: Re: beta
PostPosted: 23 Dec 2020 11:01 
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Skipper

Joined: 09 Aug 2017 15:35
Posts: 725
Location: Maine/USVI
This is interesting (zinc anode line cutter):
https://www.seashieldmarine.com/product ... ding-zinc/


 
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 Post subject: Re: beta
PostPosted: 23 Dec 2020 22:33 
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Skipper

Joined: 14 Jul 2012 20:36
Posts: 495
Location: Norfolk, Va
Maineiac wrote:
This is interesting (zinc anode line cutter):
https://www.seashieldmarine.com/product ... ding-zinc/


On ours we don't have room to fit between the cutlass and prop. Also as a former diver, I can say they will take your name. Please let any driver know you have one.

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Hull #208, Puff Card
Southern Chesapeake Bay


 
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 Post subject: Re: beta
PostPosted: 24 Dec 2020 11:40 
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Skipper

Joined: 09 Aug 2017 15:35
Posts: 725
Location: Maine/USVI
I am putting a shark line cutter on the shaft. I just thought the anode version was interesting. I spent decades resisting, but going over the side with a dive knife and a line tied around my waist just doesn't interest me anymore. I've done it a dozen times. No fun. And I've never had a diver scrub my bottom. But of course, I'd warn anyone in the water around the boat.

Until you've gone up the Damariscotta River amongst the toggles and buoys, you haven't SEEN lobster warp.


 
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 Post subject: Re: beta
PostPosted: 31 Dec 2020 23:14 
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Skipper

Joined: 29 Dec 2006 09:38
Posts: 656
Not sure why you resisting. My lobster fisher friends say they expect to lose a few and tag some themselves. I have a shark cutter and it work great. I sail Penobscot area all season and usually only snag one that I have to snap. I have a feathering prop and lock it--so most of the time I can just let it go in neutral and the pot falls off. You may also know that the lobster fishermen are using a newer technique of tying longer lines of their traps together. This means losing one buoy is not necessarily the loss of a trap. Also, few buoys needed on a line.
Ray Durkee


 
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 Post subject: Re: beta
PostPosted: 01 Jan 2021 12:06 
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Skipper

Joined: 09 Aug 2017 15:35
Posts: 725
Location: Maine/USVI
Velera wrote:
Not sure why you resisting. My lobster fisher friends say they expect to lose a few and tag some themselves. I have a shark cutter and it work great. I sail Penobscot area all season and usually only snag one that I have to snap. I have a feathering prop and lock it--so most of the time I can just let it go in neutral and the pot falls off. You may also know that the lobster fishermen are using a newer technique of tying longer lines of their traps together. This means losing one buoy is not necessarily the loss of a trap. Also, few buoys needed on a line.
Ray Durkee


At $100/trap or more, plus line & floats, a 10 trap string is easily over $1,000.00. I resist out of respect. I grew up in Sandy Point. With a couple of notable exceptions in Rockland, I'd respect and try to salvage gear if I had to cut it off my prop shaft. Tie floats back on lines and toggles. Family members and friends were lobstermen, and just cutting people off without thinking twice isn't quite cricket. I'll admit, thousands do it annually and couldn't care less. But the last multi-trap string I had to cut off in the South end of the Reach I felt pretty bad. But you got guys out there that think "I got cutters, so I can go anywhere without worry." Give the Darmiscotta a run up to E. Boothbay some time. I've done it at night in a thunderstorm with a 12 year old on the bow calling the shots. Harrowing.


 
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