371 - Correct Propeller size

Correct Propeller size

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Category: Hints & Tips
Forum Name: 371
Forum Description: 371 Hints and Tips
URL: https://www.myhanse.com/forum_posts.asp?TID=13280
Printed Date: 27 March 2026 at 03:41
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Topic: Correct Propeller size

Posted By: Paule70
Subject: Correct Propeller size
Date Posted: 24 March 2022 at 21:40

Dear All,

I have currently a Volvo MD 2030 29 hp @ 3.600 rpm with a MS25 reducing 2.47:1 driving a 16 inch 2 blade flexofold folding prop with unknown pitch.

I want to upgrade to a 3 blade flexofold folding prop.

As an option I will at the same time upgrade to a Volvo MD 2040 40 hp @ 3.600 rpm with same 2.47:1 MS25.

after goimg through all posts I could find but I am still a little bit confised… and even more confusing flexofold offers for the 40 hp option a 17x11 3 blade prop. I understood that some of you uses such size for 29 hp. after a longer discussions with flexofold headquarter they still confirm 17x11 for 40 hp. unfortunately I dif not ask for 29 hp to get an comparison.

Easiest for my issue would be to give your recommendations of prop sizes for

a: 29 hp

b: 40 hp

Hope to get so,e answers from your swarm intelligence.

Best regards

Robert

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Hanse 371 #129
Eckernförde, Germany

Replies:

Posted By: Paule70
Date Posted: 25 March 2022 at 18:20

@lucca

I saw,in your signature that you use a 3 blade folding prop with a 40 hp Volvo.

I would be happy to learn what size the prop is and whether you are happy with its characteristics.

Thank you in advance.

Greetings, Robert

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Hanse 371 #129
Eckernförde, Germany

Posted By: lucca
Date Posted: 03 April 2022 at 10:01

Hi there

I have an Volvo 18x13 3-blade folding propeller for my MD2040 40HP @3600rpm (Part no. 3581225). I am very satisfied with that. The engine does it easily.

No wind and wave:

@1800 rpm --> 5kn

@2100 rpm --> 6kn

I've never needed RPM's higher than 2600 rpm. Then the stern gets stuck in the water.

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371s #171, 40HP Volvo, 3-Blade FoldProp, Jefa RP150&DD1, RMC 185 4kW, Zeus2 9, V50, NAIS400, WR10, Victron MultiPlus 1600, 180W Solar, 150l Diesel, 300l H2O, Eberspächer 4kW, freezer ... ;)

Posted By: karina
Date Posted: 20 April 2022 at 19:18

Hi all,

since 2014 I have a 17x12 2-blade flexofold propeller (MD2030, 29HP). The size was recommended by the flexofold "expert" on the Hanseboot exhibition.

I'm very happy with this prop.

approx. @2250 rpm --> 6kn

approx. @2650 rmp --> 7kn

full speed approx. @3000 rmp --> 8kn (no wind, no waves, clean hull)

From my point of view, there is no need to upgrade to MD 2040. Better spend the money for fast sails ;-)

BR,

Rainer

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live slow - sail fast!

S/Y Karina

Hanse 371 #32

Hamburg / Germany