MaxProp and Hydraulic Gearbox

Goldie

Goldie

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A gearbox problem means that a replacement gearbox is required. Rather than replace with the same again (ZF15M on a Beta BV2203 50hp) it’s been suggested that I consider fitting a PRM150 hydraulic ’box. A local boatyard has the same pairing on a workboat with several thousand hours run and having seen it demonstrated, it is impressively smooth and quiet on engagement compared with ZF. There’d be some engineering involved to fit the PRM, but before we get into costing it, I have a question please.

My boat is fitted with a MaxProp, how will the pairing of that with a PRM 150 hydraulic ‘box cope with feathering the prop? The MaxProp currently depends on the locking action of the gearbox for the blades to assist the feathering process, the engine being shut down in forward gear.

Hydraulic gearboxes are something I’m not familiar with so advice would be very much appreciated please.

Thanks in anticipation.

P.S. If the ZF15M is to remain an option, please can anyone steer me in the direction of one? So far, I’ve been quoted a 16 week lead time! Thanks.
 
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Goldie said:
A gearbox problem means that a replacement gearbox is required. Rather than replace with the same again (ZF15M on a Beta BV2203 50hp) it’s been suggested that I consider fitting a PRM150 hydraulic ’box. A local boatyard has the same pairing on a workboat with several thousand hours run and having seen it demonstrated, it is impressively smooth and quiet on engagement compared with ZF. There’d be some engineering involved to fit the PRM, but before we get into costing it, I have a question please.

My boat is fitted with a MaxProp, how will the pairing of that with a PRM 150 hydraulic ‘box cope with feathering the prop? The MaxProp currently depends on the locking action of the gearbox for the blades to assist the feathering process, the engine being shut down in forward gear.

Hydraulic gearboxes are something I’m not familiar with so advice would be very much appreciated please.

Thanks in anticipation.

P.S. If the ZF15M is to remain an option, please can anyone steer me in the direction of one? So far, I’ve been quoted a 16 week lead time! Thanks.
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Anyone??? Please!
 
I guess no-one knows, but surely the people at MaxProp could give you advice? If not, try one of the many marine engineers down your way. The question must surely have arisen before.
 
sailorman said:
I have a Nanni 4150 HE with the PRM150, i fitted this set-up 18 yrs ago, It replaced a Perky 4108 with a TMP hydraulic box.
The new is more efficient i had the coarsen the MaxProp to get thr rpm down below 3k.
Go 4 it
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That’s really good to know, thanks. What about feathering the prop? What is your feathering process, do you stop the engine in gear?
 
Goldie said:
That’s really good to know, thanks. What about feathering the prop? What is your feathering process, do you stop the engine in gear?
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out of gear normally, but occasionally towards the end of the season & dependent on boat spd it might not feather, so restart engine, put it in astern, take out of gear, turn off engine & it will feather.
My MaxProp is a 2 blade, fitted the boat when we bought her over 21 yrs ago. I assume you have a 3 blade
 
sailorman said:
out of gear normally, but occasionally towards the end of the season & dependent on boat spd it might not feather, so restart engine, put it in astern, take out of gear, turn off engine & it will feather.
My MaxProp is a 2 blade, fitted the boat when we bought her over 21 yrs ago. I assume you have a 3 blade
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Yes, 18” 3 blade. I wasn’t expecting to stop in neutral as I thought the prop needed some rotational resistance to help it feather and I’m intrigued by the fallback method, but if it works, it works! No shaft brake I take it? Many thanks for the really useful input. Any feedback on the a PRM 150 would be appreciated.
 
no brake needed with feathering prop
why not start another thread on PRM 150 info
When i bought the Nanni, it was going to have a PRM 150 anyway as i had a hydraulic box previously, chatting to Peachments they said the PRMs were fitted to Broads hire boats as they can withstand misuse better than the mechanical box`s
 
sailorman said:
no brake needed with feathering prop
why not start another thread on PRM 150 info
When i bought the Nanni, it was going to have a PRM 150 anyway as i had a hydraulic box previously, chatting to Peachments they said the PRMs were fitted to Broads hire boats as they can withstand misuse better than the mechanical box`s
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That’s all really useful and much appreciated, many thanks indeed. The yard likely to be doing the work are recommending PRM for the same reasons.

Fair Winds
 
If it is any help I have a Prm 140 gearbox driving a Darglow Featherstream feathering propellor. If you put it in neutral before stopping the engine then it won't feather and continues to rotate with the waterflow. The trick is to switch the engine off first whilst at forwards idle as this stops the shaft rotating before the hydraulic pressure in the gearbox decreases sufficiently to release the clutch and alow the shaft to rotate.
 
captainboo said:
If it is any help I have a Prm 140 gearbox driving a Darglow Featherstream feathering propellor. If you put it in neutral before stopping the engine then it won't feather and continues to rotate with the waterflow. The trick is to switch the engine off first whilst at forwards idle as this stops the shaft rotating before the hydraulic pressure in the gearbox decreases sufficiently to release the clutch and alow the shaft to rotate.
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The Featherstream has a larger boss than my 2 blader, so may be the reason for that
 
captainboo said:
This may be of help:- PYI Inc. | Max-Prop Automatic Feathering Propellers

Under FAQ towards the bottom it lists 'What is the correct procedure to feather my Max Prop?' which for a hydraulic box is exactly the same as I do.

I should have mentioned that stopping the engine in forward gear with my Featherstream is the method stated by Darglow themselves.
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Thanks. Unfortunately the waters are being muddied by the engine manufacturers (who would potentially supply the hydraulic box) who ‘doubt’ that there would be sufficient residual pressure to facilitate feathering during the shut down process.

All. Many thanks for all who have contributed to this thread and expanded my knowledge enormously. However, it looks as though there would be an enormous amount of engineering work required (shortening shaft, raising engine mounts, moving Aqua-drive etc - which would add a haul out to the cost too) to make the hydraulic box fit so, having finally found a direct replacement mechanical box in Holland, I think that’s the way I’m going to go. I think the hydraulic would ultimately be a better solution, but one that’s probably not a cost effective retrofit. Thanks all, but from my perspective I think we an draw this thread to a close.
 
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