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Folding Propeller

Printed From: myHanse.com
Category: Hints and Tips
Forum Name: 385/388
Forum Description: 385/388 Hints, Tips and News
URL: http://www.myhanse.com/forum_posts.asp?TID=12890
Printed Date: 17 October 2021 at 13:03
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: Folding Propeller
Posted By: haifligher
Subject: Folding Propeller
Date Posted: 20 July 2021 at 08:10
Hi everyone, we have the 2 blade folding propeller on our 388, with the upgraded 39hp engine. All ok in general, but it always feels like we need higher revs to get the boat going. Perhaps normal? Anyone has experience with a 3blade propeller? Thats what a friend recommend to get more torque (in the harbour) and same speed with less revs and burning less Diesel. Plus less problems with cavitation. Theoretically that sounds good and logical. Now our techguy who is also in charge for many charter boats told me, he would not use the (heavier) 3 blade folding prop, as that might create problems with the sail drive. Of course we talk about the prop, on the Yanmar list. Grateful for ideas and suggestions. Leave it and live with it? 
Thx, Christian 



Replies:
Posted By: Matt1
Date Posted: 20 July 2021 at 10:14
I can’t comment on a 388 but I swapped the std x2 blade fixed prop for a x3 blade flex o fold on my 418 and as expected it was transformational - both under sail and power. Under power it provides increased top speed and cruising speed, more power into a head sea and wind, and better close quarters handling. can’t recommend it enough 

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Hanse 418 #64 EmBer. Hamble, UK



Posted By: Scribble
Date Posted: 20 July 2021 at 11:31
Hi
I agree with what you are saying wholeheartedly. Feels like too many revs to get 6 knots on such a large engine and I feel like I wish I had the folding 3 blade too. Good to hear about Embler's success.
Tony


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Tony - Hanse 388 Scribble


Posted By: Matt1
Date Posted: 20 July 2021 at 12:17


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Hanse 418 #64 EmBer. Hamble, UK



Posted By: Matt1
Date Posted: 20 July 2021 at 12:19
Engineering beauty ;)




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Hanse 418 #64 EmBer. Hamble, UK



Posted By: S&J
Date Posted: 21 July 2021 at 07:02
What revs do you need for 6kts?
On my 2015 385 with the standard Volvo D1-30 and a Gori two blade folding prop I needed 2,000 revs to get 6kts in flat water.
I felt this was a comfortable speed to motor.
Over 500 hours I averaged 2 litres fuel per hour.

I would definitely recommend having a folding prop rather than fixed blades.


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H458 #159 Primal heading to the sun


Posted By: haifligher
Date Posted: 22 July 2021 at 09:10
hi, thx for your replies. We have to check the exact data, but sure we need more than 2000 revs to get 6knots. And we’re using around 3liters / hour, also difficult to judge as we also used the Diesel heater quite a lot. I‘m just wondering about the real adavantage of the bigger engine, if the extra power does not transfer to the blade. Well, not as expected… and maybe that is  the problem? We are happy with the fact that its a  folding prop, specially sailing. Changing now (an only one year old 2 blade folding prop) to a 3 blade… thats what we think about. Will check Mikaels data (highly recommend!), what his setup comes up with. Still the question about the extra weight and damaged saildrives. Anyone heard of that?
Happy sailing! Christian 


Posted By: S&J
Date Posted: 22 July 2021 at 09:49
I always felt to 30hp was sufficient.  
On the 458 the larger 80hp  engine is basically the 57hp plus turbo which needs high revs to get to temperature for the turbo, consequently high consumption.
I do get instant fuel rates on this boat and it shows that I get 6kts at 1800 revs, about 3l/hour   Now have 3 blade flexofold.


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H458 #159 Primal heading to the sun


Posted By: Matt1
Date Posted: 22 July 2021 at 10:55
Originally posted by haifligher haifligher wrote:

Still the question about the extra weight and damaged saildrives. Anyone heard of that?
Happy sailing! Christian 
 
I was surprised how heavy and how long the 3xblade f-o-f is when folded and did wonder about all that weight / forces / leverage hanging off the saildrive. But the saildrive itself is pretty heavy and I'm sure it's robust enough. I'm also reassured that f-o-f are ultimaely owned by Yanmar so its the same "group" to deal with if you get any problems I guess (Easier for Yanmar to blame Gori or Bruntons etc than their own sister company) 
 
I'd be surprised if 30hp wasn't plenty. The std 418 only has 9hp more and I've never really needed any more power yet.


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Hanse 418 #64 EmBer. Hamble, UK



Posted By: Rock
Date Posted: 22 July 2021 at 14:18
3 blade flexofold on my 40 hp 400e works like a dream.
1900 Revs, some 6.5 knots
I went to the high end of what flexofold recommended, rev’s max out at some  2950 (almost 7.9-8 knots)
Fuel consumption between 1.7-2 liters per hour.

The prop being too heavy for the sail drive, increasing forces on the saildrive ?
Think about the forces on the saildrive (even with a lightweight fixed 2 blade Alu prop) when 8000 kg’s are forced into heavy wind and waves

Also, the SD50 is spec’d up to 75 HP, a 75 HP engine would have a heavier prop anyway.
My SD60 is spec’d for 100 HP

BR
Peter 


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Hanse 400e "M-square2" #0241


Posted By: High Time
Date Posted: 22 July 2021 at 14:26
Originally posted by Matt1 Matt1 wrote:

I can’t comment on a 388 but I swapped the std x2 blade fixed prop for a x3 blade flex o fold on my 418 and as expected it was transformational - both under sail and power. Under power it provides increased top speed and cruising speed, more power into a head sea and wind, and better close quarters handling. can’t recommend it enough 

Hi Matt
I'm curious what size 2 and 3 blade props you have used. On High Time with the Volvo D2/40 I have the 17 x 14 L 2 blade Flex-o-Fold and, if anything, it feels slightly over-propped. 2000rpm gives me 6.5knts in calm water and max revs (slightly less than 3000) gives around 8.5 knots.m It revs to around 3500 out of gear.

I usually cruise at just under 2000rpm and over many seasons have averaged around 2.4L/hr. 


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Roger

High Time (415 #038)


Posted By: Matt1
Date Posted: 22 July 2021 at 16:18
Originally posted by High Time High Time wrote:

[QUOTE=Matt1]
Hi Matt
I'm curious what size 2 and 3 blade props you have used.
 
(Not sure if the below will display correctly, but will try - prop size is at the bottom of the table). This was a reasonably scientific experiment as "before" & "after" were both just after relaunch so with a pristine bottom and in essentially the same conditions
 
 
 93.54% Log calibration. Fully laden, 10kn TWS@30deg TWA, smooth sea93.54% log calibration  1/2 laden,                       10-12kn TWS @30deg TWA,  smooth sea
RPMSpdSpd
700n/a2.8
10002.63
11002.83.1
12003.23.2
13003.43.5
14003.84.4
15003.94.6
16004.34.9
17004.55.6
18004.75.8
19004.96.1
20005.16.4
21005.56.8
22005.77
230067.1
24006.37.3
25006.57.6
26006.6 
27006.97.9
28007.18.2
30007.52900 max revs
32007.8n/a
Prop18" X ? Pitch x2 blade17" X 14" X3 blade f-o-f
 
 


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Hanse 418 #64 EmBer. Hamble, UK



Posted By: haifligher
Date Posted: 22 July 2021 at 21:05
 Thx so much Matt, Tony, S&J, Roger, Peter… everyone! 
I‘m amazed how much information we‘ve got from all of you in such a short time Smile
I will try to collect more data and let you know…
Cheers!


Posted By: MasterKeil
Date Posted: 25 July 2021 at 19:56
I had the flexofold 3 blade foldable prop as upgrade on my 2009 370 40 hp Yanmar. I was not happy with the stopping distance and RPMs at 6,5 kts, which were above 2000 RPM. So I called flexofold and they suggested a Prop with a higher pitch. As my prop was nearly brand new, they changed my prop for one with a higher pitch for free. Since then my cruising speed of 6,5 kt needs 1800 RPM and the stoping distance is a lot shorter. Yanmar requests the higher RPMs because Diesel with sulfur is also allowed for the engine; but in Europe the Diesel is nearly sulfur free, so the high RPMs are not needed to keep the engine clean.

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Hanse 370#640 "Nemesis"


Posted By: PieterH
Date Posted: 26 July 2021 at 18:13
I have the standard 27HP with a standard 2 blade fixed prop and get just about 5 kts at 2200rpm on flat water. This season only daysails and no long passages, so no real issues, but I takes a long time before I get steerage in marina handling going from forward to reverse and it can be a big problem with a strong tide. This can take between 5-7 seconds and that's scary on spring tides in the Hamble river. In winter I will upgrade to a 3 blade flex prop.



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H388 # 191 Manzano


Posted By: haifligher
Date Posted: 07 September 2021 at 10:28
  Hi again, 
we checked all documentation but could´nt find anything on the propeller.
It´s a Gory 2 blade folding prop. But what size and pitch? Sure we can find out in winter storage, but perhaps anyone knows? We have the upgraded engine with 39hp. Interesting to know what foldable prop is used with the standard engine… It should not be the same propeller, otherwise the extra power does not make any sense, right? 
Thx! Christian


Posted By: Bruno
Date Posted: 08 September 2021 at 20:48
Would you think that a folding prop, 2 or 3 blades, would create more stress on the SD50 clutch and glaze faster than a fix prop? No shaft revolution while sailing vs more force exercised on the transmission for the same RPM.


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Bruno

Hanse 400, 2010 Hull 660, sailing lake Champlain, VT USA


Posted By: haifligher
Date Posted: 08 September 2021 at 21:03
hi bruno, its not about fixed vs folding prop. We have a 2 blade folding prop, but we wonder if this is the right size and pitch considering we have the upgraded engine. Nearly all rev/speed data matches the data of the standard engine. Except we need a lot more Diesel. And, that was part of the original question, we were told that a three blade prop (folded) maybe to heavy for our saildrive. But: That seems to be ok (thx for the answers) and in addition flexofold (part of Yanmar) confirmed this. We are still wondering, if we now have the appropriate prop for our boat. Changing to three blade is an option. 
Enjoy 😊 


Posted By: Scribble
Date Posted: 14 September 2021 at 15:26
Hi everyone
has anyone any experience of the Brunton Autoprop Variable pitch propeller or the Darglow Featherstream I saw at the Southampton Boat Show? I definitely need a better prop next year than the standard 2 blade Gori folding prop supplied for my 40hp Yanmar!
Cheers Tony
Scribble


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Tony - Hanse 388 Scribble


Posted By: Matt1
Date Posted: 14 September 2021 at 17:30
I had a featherstream on my last boat and loved it. I would have chosen it for the Hanse but decided to go flex-o-fold simply because when folded I figured it presented a smoother profile that was less likely to snag on pot marker lines etc 

Different boats and different configurations etc but I think the flex o fold has less prop walk (not always a positive!) In other regards performance was comparable 


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Hanse 418 #64 EmBer. Hamble, UK



Posted By: Scribble
Date Posted: 14 September 2021 at 19:55
Thanks Matt for your thoughts again, much appreciated! Tony

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Tony - Hanse 388 Scribble



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