folding prop Martec Elliptical versus Flexofold

[keeljoy]

I am buying my first folding prop for a Ranger 29. I've narrowed the choices down to Flex o fold two blade or a Martec two blade. I know the differences as geared or not. I've read the performance review from 2009. The flexofold is about $300 more. Does either one vibrate more than the other. Which costs the most in terms of forward thrust (I am converting from a three blade fixed.) Is the drag noticeably different? which one will assure me that I will win my racing class

Recommendations?

[robert sailor]

The Ranger 29 is a great little PHRF racer, you'll have a lot of fun with it. The Martec folder gets the job done but it's weak in reverse and in light air if the prop doesn't stop horizontally one of the blades can droop. The Flexofold is a much better prop, it is very powerful in forward and OK in reverse and the blades always fold together because they are geared. If you can afford it I would go with the Flexofold. We used to mark the shaft when using the Martec's and hand turn it so the prop was horizontal when racing.

[keeljoy]

Whats been amazing is how badly the boat sails with a fixed three blade prop. Not that we don't make mistakes ourselves, but not only
does it cost us in general speed, our tacks can come almost to a dead halt, and we can't point nearly as well windward. ..especially with a strong current.

[robert sailor]

Originally Posted by keeljoy

Whats been amazing is how badly the boat sails with a fixed three blade prop. Not that we don't make mistakes ourselves, but not only
does it cost us in general speed, our tacks can come almost to a dead halt, and we can't point nearly as well windward. ..especially with a strong current.

Well you might have to look at other causes as a folder won't really give you much help for general pointing. If the wind is strong enough there is not a lot of difference between a fixed and folding prop but in the lighter winds the difference is quite a bit, much more than the extra handicap allowed under PHRF. If you want to be competitive in racing you need a folding/feathering prop, its just that simple but if you can't point well in normal conditions you need to look at how you are sailing which covers lots of stuff including the condition of sails. If your sails are crap and you don't set the fairleads properly and trim the sails properly and sail properly you can't blame the fixed prop. Anyways good luck in your sailing/racing, there is much to learn and nothing will teach you faster how to sail properly than racing. It will take you a couple of years to really get a boat dialed in but your choice of the Ranger was a good one but you have to do your part.

[keeljoy]

I totally get that :-) We've been working hard on trim, the sails are very good, we've been gutting weight, new bottom paint, upgrading rigging etc. But we are 225 (NFS) and can't seem to even live up to that. I used to race a Thunderbird which was very responsive to various tweaks and improvements (and a blast to sail)

[Jim Cate]

FWIW:

On our previous boat (old IOR one-tonner) we had a Martec elliptical two blade. As reported above, it sometimes failed to fold the downward-pointing blade in light airs, it had very poor performance in reverse, and it wore to the point of requiring expensive repairs by the time we reached New Zealand (don't remember how many hours this was, but around 1500 or so, possibly 2000. It performed very well going forward, and had low drag sailing.

On this boat we installed a Flex-O-Fold three blade. It always folds evenly, has excellent performance going forward and acceptable in reverse, and after over 3000 hours, no perceptable wear.

I think that if you can afford the difference, the FOF will be a better prop. Either one will reduce drag sailing... no great difference there, so winning is up to you!

And again FWIW, many years ago when actively racing my Yankee 30 in the SF area I went from middle of the fleet to winning when I changed from a fixed two blade to a two blade folder. I was impressed with the difference... so were my competitors!

Jim

[Roy M]

Jim, what wore out in the Martec? I haven't put many hours on my Mark III Elliptical, and I certainly agree about the operating characteristics. A friend just lost his Gori three blade, so I'm certainly at a loss for options. A folder, though, is not in question for me, as I love the ability to sail through a kelp bed without picking up strands of weed, and I'm greedy for speed.

[Dave Lochner]

My last boat (a Sabre 30) had a Martec prop. Initially it was weak in reverse, however, after having Martec refurbish it, reverse was fine with much less prop walk than my current MaxProp has.

Complaints about Martecs in reverse are almost always due to the blades needing to be reconditioned. It was a few years ago when I had it done and the cost was around $225. It was the first time in 20 or so years that the prop had been reconditioned.

If the blades are horizontal in light air, the lower blade may droop. Mark the prop shaft so you know when the blades are vertical and turn the shaft so that the blades are vertical and put the transmission in gear.

If the tips of the blades are closer than about ¼" then it is time to send the prop back to Martec and you will get a like new prop back.

With either prop you will see an improvement in boat speed especially in lighter air, perhaps as much as 1 knot difference.

As for choosing, look at your budget. $300 will buy a couple of new VPC Halyards or light air sheets or other go fast items.

Dave

[keeljoy]

All well thought out comments. I noted on Monday that I finished 5 minutes actual and 3 minutes corrected 5th of 5 boats 14 minutes behind the leader. If I had gained .5 knot from a folder I would have won the whole NFS class by 2+ minutes and corrected to 5+ minute win.

[keeljoy]

Seems clear to me, I'll be sure to update the forum afer we install the flex o fold.

[Dave Lochner]

Originally Posted by Roy M

Jim, what wore out in the Martec? I haven't put many hours on my Mark III Elliptical, and I certainly agree about the operating characteristics. A friend just lost his Gori three blade, so I'm certainly at a loss for options. A folder, though, is not in question for me, as I love the ability to sail through a kelp bed without picking up strands of weed, and I'm greedy for speed.

There are 2 areas on the Martec that wear, the hole for the pivot pin and the root of the blades. These areas will cause the Martec to close too much and not open quickly enough in reverse.

Quick changes from forward to reverse will cause the blades to slam open or closed. I think that this slamming causes the blades to wear more quickly.

Dave

[Jim Cate]

Originally Posted by Roy M

Jim, what wore out in the Martec? I haven't put many hours on my Mark III Elliptical, and I certainly agree about the operating characteristics. A friend just lost his Gori three blade, so I'm certainly at a loss for options. A folder, though, is not in question for me, as I love the ability to sail through a kelp bed without picking up strands of weed, and I'm greedy for speed.

Roy, the wear was between the pins and the bores in the blade bases. The cure is to enlarge the bores enough to true them up and then make up new pins to match the size. It was done in NZ and was fairly expensive, way back in 1990.

And FWIW, when we bought our present boat it had an elderly Gori two blade which was similarly worn. A repair was effected by the PO, but the machinist used a oilight bronze bushing to restore the fit and they failed within a few hours of use. This lead to the purchase of the FOF.

Jim

[Dave Lochner]

Originally Posted by Jim Cate

Roy, the wear was between the pins and the bores in the blade bases. The cure is to enlarge the bores enough to true them up and then make up new pins to match the size. It was done in NZ and was fairly expensive, way back in 1990.

And FWIW, when we bought our present boat it had an elderly Gori two blade which was similarly worn. A repair was effected by the PO, but the machinist used a oilight bronze bushing to restore the fit and they failed within a few hours of use. This lead to the purchase of the FOF.

Jim

I'm not sure how Martec refurbished my prop, however, it was clearly not by enlarging the hole and using a larger pin. I suspect that they filled the hole with bronze and then drilled new holes and brazed on more material at the root and machined it to specs.

Dave

[Cheechako]

If the Martec hasn't changed over the years they are useless. Very poor thrust especially in reverse. I've raced with people who had them. To me it would be a downgrade from a fixed prop.

[robert sailor]

Originally Posted by keeljoy

All well thought out comments. I noted on Monday that I finished 5 minutes actual and 3 minutes corrected 5th of 5 boats 14 minutes behind the leader. If I had gained .5 knot from a folder I would have won the whole NFS increases in speed of a 1/2 knot class by 2+ minutes and corrected to 5+ minute win.

Its not hard to achieve increases in speed of a 1/2 knot especially coming from a 3 blade fixed prop but you need light air to gain that speed, the lighter the air the more effect the folder has on boat speed. Having said that I see you are from Seattle which is a light air area. Make sure your bottom is nice and clean and remember that your rudder can be a big speed brake if over used. Good luck in your racing and let us know how you do with the new prop. Are you racing with white sails only or are you using flying sails? Also remember boat speed is a bit player compared to tactics but its nice to have both going for you.