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3JH5E / SD50 saildrive ratio & prop

Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 400
Forum Description: 400 Hints, Tips and News
URL: https://www.myhanse.com/forum_posts.asp?TID=15107
Printed Date: 27 March 2026 at 03:41
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Topic: 3JH5E / SD50 saildrive ratio & prop
Posted By: MartinR34
Subject: 3JH5E / SD50 saildrive ratio & prop
Date Posted: 13 May 2025 at 13:22
Hi everyone. I am new to the Forum having just agreed to complete on a 2010 Hanse 400. Really looking forward to getting her on the water but quite a bit of work is required first.
I suspect I will be on here a lot researching and asking daft questions!  The first of which are below LOL (apologies if these have been covered in other posts - I did do a search but didn't see anything obvious).
She has the Yanmar 3JH5E 39 hp engine and SD50 saildrive. The SD50 is very badly corroded and has been condemned by the surveyor. I will therefore be replacing with a new SD60.  
Does anyone know what gear ratio the SD50 will be, so that I can order the correct ratio in the SD60?  The boat is several hundred miles away in Scotland UK (I am in south east England) so I cannot easily check.
She also needs a new prop as this has been eaten away too. I am in two minds as to whether to buy a fixed 3-blade or a feathering 3-blade. I have had a feathering KIWIprop on my last boat which was great for sailing but a little less reliable motoring(!) and required drying out and greasing every 6 months. I don't fancy doing this on the Hanse as it will require a spring tide to access the drying grid. Has anyone got any experience of the Darglow Featherstream?  Is it worth the extra (significant) cost over the fixed prop?
Finally, what rope cutter are people generally using?
Thanks very much for your help.
Martin



Replies:
Posted By: alidal
Date Posted: 13 May 2025 at 17:39

I have a new SD  60 gear ratio 2.23 :1

The old sd 50 had gear ratio 2.32 :1

I have a 2-blade Flex-O-Fold, 17 x 14 LH

That fits my boat, Hanse 400, 2010.



-------------
Hanse 400#655


Posted By: Ratbasher
Date Posted: 13 May 2025 at 17:47
Hi Martin; welcome to the forum and congratulations on buying what is basically a well-designed boat for its purpose.

I'm sure others more knowledgeable about the clanky stuff will chip in but I would say don't go for a fixed prop; far too much drag.  I have the Flexofold which has performed well but I reckon I'd be equally happy with the Darglow. Only needs servicing on annual lift-out. I understand that there's a dedicated ropecutter for the SD60 but the scissors type that I've been using on my SD50 has successfully sliced through several crab pot lines.  Given a recent (and ultimately needless) scare myself I looked into replacing my SD50 with the 60 and I gather its quite straightforward with an adapter plate.  No way I'm clever or brave enough to do the job myself so my efforts would be restricted to paying a Yard. 

I hope the Surveyor has provided a comprehensive explanation of why the old SD and prop melted away so thoroughly and what to do to stop it happening again.  It would indicate a lack of care by the former owner so caveat emptor applies, as ever.

Do play around with the 'advanced search' button looking carefully at the options.  There's probably few issues that someone hasn't suffered in the past and there's certainly plenty of stuff on corrosion in SD legs.

3JH5E - or 3JH4E?  

Do remember that the only stupid question is the one that you don't ask.

Iain


-------------
H400 (2008) 'Wight Leopard' Gosport, UK


Posted By: MartinR34
Date Posted: 13 May 2025 at 17:54
Originally posted by alidal alidal wrote:

I have a new SD  60 gear ratio 2.23 :1

The old sd 50 had gear ratio 2.32 :1

I have a 2-blade Flex-O-Fold, 17 x 14 LH

That fits my boat, Hanse 400, 2010.


Thanks for your reply.


Posted By: MartinR34
Date Posted: 13 May 2025 at 18:17
Thanks for your reply Iain.

I have a feathering prop on my old (as yet unsold!) boat and it adds at least a knot of boat speed when sailing, but they are expensive...

The saildrive was galvanic corrosion - the previous owner had the boat in the water, moored in a marina and plugged into shore power, and it was unused for 2.5 years. The anodes were gone and sadly, chunks of the propeller and the structural integrity of the SD50!  I'll be checking all of the electrical bonding, etc.

Agreed the change to the SD60 should be straightforward with the plate - just expensive!  I'll probably fit the HydroAxe cutter.

It is the 3JH4E - typo error Wink.

She is a two owner boat, last owner since 2014. I am replacing the standing rigging, the saildrive, propeller, and the seacocks, all of which are original. I am then adding a bowthruster as I often sail single-handed and she is just that bit bigger than my current Westerly (I am hoping not to need it very often, more for peace of mind). I will also be adding heating, an AIS transceiver and, probably over the winter, the full width swim/bathing platform as she has the open transom and twin wheels.

She is now ashore and I am hoping to have her moved to the south coast in early June, with launch any time from mid-June onwards - the SD60 is on a 6-8 lead time unfortunately so that is delaying things.

Martin


Posted By: jeb
Date Posted: 14 May 2025 at 07:20
The SD50 has 1:2,32 and the SD60 1:2,23 or 1:2,49. I have a FlexOFold 18x12 3L on my Hanse 400 with 3JH4/SD50 and that is a good match. With the 1:2,23 i would probably use the same pitch but with a 1:2,49 I would go up to 13 inch pitch.

-------------
Jesper
Hanse 400e


Posted By: MartinR34
Date Posted: 14 May 2025 at 10:03
Thanks for your reply. I'll certainly be looking at the Flexofold props.



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