Hylas Yacht Owners Association Forum

Open Discussion => Hylas Discussion => Topic started by: snailor on May 16, 2020, 02:24:55 AM

Title: Max Prop conversion to Flexofold
Post by: snailor on May 16, 2020, 02:24:55 AM
Hi all.

I've heard some of the H46s out there have switched from Max Prop to Flexofold.  Our own Max Prop is due for yet another rebuild and I'm weary of the time and cost of keeping our 19-inch classic going.  We had great success with our Flexofold 2-blade on our last boat so I'm hoping the 3-blade 18-inch will at least equal if not outperform the Max Prop.  Our Max Prop, which is driven by a Yanmar 4JH3-TE with a KBW21 2.17 reduction gear, pushes the boat well under most conditions but with time, the blades loosen on the hub and sometimes vibrate when motorsailing.  While we can overcome this by increasing revs, we'd like to be able to throttle back and let the wind do some of the work. Only another rebuild will tighten the blades and reduce the vibration.  Including the yard bill, the cost to remove, ship, rebuild, ship and reinstall the Max Prop approaches that of a new Flexofold.

We would appreciate having specifics on the size, pitch and other key measurements for an 18-inch Flexofold on any other H-46s and any comments on how this propeller has performed on other H-46s.  We are also having to base the taper on the existing Max Prop so if anyone has the taper and thread measurements for the 1-1/2 inch shaft, that would also be helpful.

S/V Santosha H-46 #034
Title: Re: Max Prop conversion to Flexofold
Post by: Obsession on May 16, 2020, 12:51:15 PM
I used a Flex-O-Fold on my 44/45.5.  It performed well.  It was a three-blade and the pitch was a 16 or 17.  It was on a 1.5-inch shaft with a standard taper.  They allow at least one free exchange of blades.  I found that the people at the company provided the best information given that they provided many units to owners.  The fact that it does not require continued maintenance is a big plus.  And it cost way less.  Give them a call and see what they have to say. 

Jim Halter
Title: Re: Max Prop conversion to Flexofold
Post by: snailor on June 11, 2020, 08:59:33 PM

Thanks for your reply.  We've ordered a FLexofold 18-inch three-blade with 11 pitch.  We'll see how this does once we get it installed.

Title: Re: Max Prop conversion to Flexofold
Post by: fetchinglight on July 30, 2020, 12:47:21 AM
Hi Sailors
We owned a new 2004 H46 and sailed over it 50,000 nm over 8 years.  Before we bought, I checked the the factory engine/transmission/prop match up for the 75 hp Yanmar 4JH3 engine and discovered that they were incorrect for their stock 18" fixed prop.  Hylas was following the Yanmar sales rep recommendation which did not maximize efficiency from an engineering perspective.   I brought that error to their attention and Hylas agreed to swap out the transmission to correct the error at no cost.  After delivery I installed a Flex-o-Fold 20" prop which was fine but after some careful research, I was sure I could safely increase the prop size to 22".  Theoretically, I risked overproping the engine and creating damage by lugging it.  However, since all I had to do to increase prop size was to swap out the prop blades (which can be done in the water), I went ahead because I wanted to maximize fuel consumption as much as possible.  The result was fantastic.  Fully loaded and provisioned for 6 months at sea, we were able to motor at 2200rpm making about 7 knts. in calm seas with a burn rate of .8 gal/hr.  Over the next  8 years we never had any engine or prop problems.  I seriously doubt there is any H46 out there that can improve on that performance. Flex-o-Fold props are bulletproof and highly efficient.
Title: Re: Max Prop conversion to Flexofold
Post by: brian black on August 02, 2020, 04:11:22 PM
We swapped our MaxProp for a GORI, primarily for the reasons presented.  Now the GORI is giving us problems because hard marine growth on the exposed gears builds up and prevents the blades from moving.  Does the Flexofold also have this vulnerability?