Folding Prop Desire

[ddoles]

I have a Martec, which came with the boat. It works well enough that I haven't replaced it yet, but it seems the boat is somewhat underpowered. It doesn't have much power in reverse, but once you figure that out by hitting your first dock, use more throttle and its fine. It is low drag, so when sailing its great. If/when I do replace it, Flexofold seems good from the research I've done. On a previous boat I had a three blade Maxprop. It was great in all respects, except it tended to snag and collect stuff, fishing line, etc. That is a draw back to feathering props vs folding props. I've never snagged anything on the Martec, sailing in NY Harbor with plenty of debris.

 

[debonAir]

I just installed a Flexofold 2-blade, hope to test it this week. I bought it direct from the factory in Denmark who provided good advice and support, and the price was as good as I've seen used ones listed for. It even got here in just 2 days by UPS. I had settled on a folder for the reasons ddoles mentions: avoiding catching stuff.. I wanted a geared model to get better low speed reverse (in theory) and no worry of a droopy blade at low speeds, and I settled on the Flexofold over Gori because of the test results published in Sailing World (I think) a few years back.

The only tiny negative I've seen so far is that the blade retainer pins are held in place by special tapered screws. I can see those screws being easy to lose and hard to find so I am going to get a spare set of screws and pins from a local rep.

Of course swapping the prop was part of the domino-job of fixing the rudder bearings. "With the rudder off, would be a good time to..." that eventually morphed into cutting the prop shaft off the coupler and having it shortened more and fitted/faced to a new coupler, adding a PYI flexible coupler, repacking the stuffing box, cleaning out all the gunk under the prop shaft while it was out, and then replacing the cutlass bearing because it seemed to have some play. I had the yard do cutlass though because it was hard enough just getting the prop off.

Things I learned:

Cutting the prop shaft cleanly is hard. Not only because of the material but it is hard to get to with tools. The thing that ended up working well was a 4 1/2 inch angle grinder with a thin diamond grit cut-off wheel.

There isn't much room between the shaft log and transmission. Adding the flexible coupler means I probably can't re-pack the stuffing without taking the coupler out which is a bit hard because of the access and number of bolts. Not enough room probably for a face type dripless seal, but I just found out about a drip-less "lip" seal made by Volvo that is both short and doesn't need any hoses etc. and replaces the log tube as well. It just needs greasing every year. I might replace my stuffing box and log tube with that next season.

You don't have to dig a hole to drop the rudder on an E35-3 if its blocked up a foot or so. You might need to make a small depression to put a 2x4 under to use as a lift lever.

The UHMW PE tape trick (I read about on this site somewhere) worked great on the rudder tube. I had nearly an inch of play in the rudder and adding a single wrap of 5 mil tape on the bottom and top of the stock made it rock-solid. I'd recommend getting 3 mil to start with as even the 5 was a little tight going in.

There was a little tube brazed into the bronze elbow for the exhaust at the thru-hull exit that an "anti-siphon" hose attaches too. It looked like it was brass or copper that was almost completley corroded through and it broke off easily when I was working in the stern laz. Had I not noticed I'd have raw water and exhaust pumping IN to the boat with the engine running. This is a pretty weak spot on the boat to have a thin pipe in a critical job in an area where things like spare anchors could be bumping about. People should check theirs for safety. I took the elbow out and had the prop shop drill and tap the hole where the pipe was and replaced it with a solid 1/4 NPT bronze elbow fitting. Much happier looking. The prop-shop Scandia Propeller in New Bedford MA was fantastic to deal with. Highly recommended.

 

[Loren Beach]

A friend of mine had the little (early 80's) Ericson-specific anti-syphon tube that was brazed into the exhaust thuhull replaced with a separate outlet on the rear part of the hull. It's pretty unobtrusive, being a 1/4" hose. (might be a tad larger, but it's been a while since I replaced ours)
That was a stock bit of engine water plumbing on the 80's Universal diesels. Optional on my replacement Betamarine, so I left it out and plugged the hole. Ours was just above the exhaust outlet on the transom.
This far along, and if keeping the original M25 or M25XP, I would replace with a standard exhaust fitting and a separate syphon hose outlet above it. Since both would be below normal eyesight on the curve of the hull aft, there's no esthetic downside, IMHO.

 

[imiloa]

Welcome to the site, and squinting at your avatar you may have an Ericson 31C. Perhaps. Your bio needs to be fleshed out, and most important you need a 'sig line' that gives info to quickly help others help you... like the reply from Navman in reply #2.


Do you know the sizing for your present prop? Diameter and pitch? Great that you do know the engine and shaft size; that 's a very good start.

Our hull is different, but considering props, I do have experience with the stock two blade fixed, a two blade feathering, and currently a "sailor" design three blade fixed. All have plusses and minuses. You should mess around with the 'search' function here, with the word 'prop', along with modifiers. There are a herd of good threads. This is one boat bit that is often overdue for optimization, having caused slower motoring for years or decades, as prior owners chose to ignore it.

Gotta say, for max efficiency under sail a folder is always a good bet, but they do have downsides, both in basic fit (gotta have room in front of a rudder for the blades to fold in) and their reverse thrust can be -sometimes, and very design dependent - kind of iffy.
If you have a picture of your boat's underbody when out of the water, this can really accelerate the discussion.

Finally, since this is an inquiry about running gear, I will move it to a forum where it will be seen by more members.

One year later and didn't change it yet haha thank you so much Loren..

 

[Sailingfun]

I just an order for a new flexyfold for my E27. After a lot of consideration and ask the forum, I think it's the best option. Waiting for shipping.
By the way, Axiom is now out of business

 

[Loren Beach]

Curious I am....
Did you go with the two blade or the three?

2 blade, 3 blade and 4 blade Shaft folding Propellers by Flexofold

Looking at the profile or the cross-section of our shaft propellers, you will see a powerful shape that drive boats well by converting horsepower into thrust

flexofold.com