Sun 2500 folding prop

[prvandijk]

In my Sun 2500 is a Yanmar 1GM-10 installed with a standard fixed 2-blade prop of Radice (13’ * 10). The local Jeanneau dealer could not tell me which folding prop was optimal for my Sun 2500.
Which folding prop (brand, size and pitch) is installed under your boats and how is the performance?

[rene460]

Hi Prvandijk,

Welcome to the forum. It’s good to have another 2500 on board.

There are quite a few threads specific to the 2500 in the archives, but many of the systems on our boats are common across several models in the range, so don’t confine your searches to your particular model, and propellor selection is an issue for all, governed by the same principles.

Before you start looking for a new propellor, it’s worth checking the performance of your present propellor, and whether that suits your engine and hull. The wide open throttle test is a good start. At wide open throttle the engine revs are generally recommended to top out at about 10% above the rated maximum continuous rpm in the manufacturers manual, or a little less. Also note the boat speed (with the hull freshly cleaned). This tests that the present propellor is allowing the engine to run at the right torque and speed for maximum power. The boat speed speed is ideally about the max hull speed for wave making. This information will help a propellor manufacturer make a new selection.  Also check the gear ratio of your gear box, as it is propellor rpm, not engine rpm that governs propellor performance.

It is also worth considering whether you want a folding propellor, generally the least drag for racing, but not so good in reverse if you need good reverse thrust for docking, or a feathering propellor which has only slightly more drag for sailing, but tends to give better reverse thrust.

There are many threads in the archives on other members experiences, worth perusing before you make a decision, and reading them will help you formulate questions for the manufacturer.

Several brands to choose from, and the manufacturers are the best to make the selection as so many factors are involved in propellor performance. Generally the largest that fits on your shaft while still allowing about 10% of the diameter clearance to the hull will be the most efficient in terms of more thrust per engine kW, but again only a guide. If your current propellor is a good match to your engine, it will be a good guide to the diameter of the replacement. If you can get a bit more thrust at max rpm it will be an advantage in a head wind, and allow you to throttle back a bit to save fuel when it is calmer.

I wish you success in your search. Please keep us informed of how you go.

rene460

[zaphod]

I bought a Flexofold and have been very happy with it. I saw a big improvement in sailing performance and even a small improvement in motoring speed.

You just have to tell Flexofold your boat engine and transmission model and they will spec the correct prop.

They are an oem supplier for Jeanneau so they know the boats.

[DarknStormy]

I too have installed a Flexofold on my 36i and it works well on my boat. Good performance when motoring in both forward and astern. I as well purchased what Flexofold recommended for my boat/engine/gearbox.

-- Michael

[allstar2500]

Hello Prvandijk

I too have a Sun 2500 with 1GM10.  The previous owner installed a Flexofold ISO25 14x9 2B RH back in 2013  

I would be interested to know what motoring perfromance you get from your standard prop.  My boat currently just about makes 5.5kts on a calm day.  My friends tell me that's normal as it's a French yacht designed for sailing with just enough motor power to get in and out of the marina!

All-Star

[willsun]

Prvandijk,
I have a 2006 Sun 2500 with the 1GM10 and the stock Gori folding prop. The functionality is good my issue is I’m not sure it is efficient as possible, a little more motoring speed would be nice. Whenever my wife and I are leaving the marina she always asks “Is this as fast as it goes?”. I can’t really complain though my motoring speed is 5kts at best.

[prvandijk]

Dec 19, 2022 13:00:16 GMT allstar2500 said:

Hello Prvandijk

I too have a Sun 2500 with 1GM10.  The previous owner installed a Flexofold ISO25 14x9 2B RH back in 2013  

I would be interested to know what motoring perfromance you get from your standard prop.  My boat currently just about makes 5.5kts on a calm day.  My friends tell me that's normal as it's a French yacht designed for sailing with just enough motor power to get in and out of the marina!

All-Star