VolvoPenta HS1a gearbox(es)

[Jon.M]

Hi all,

I have a 98 Broom 38 with TAMD41P and the HS1a transmission. I got the boat in Dec 22 and the surveyor noted that there was a noise/vibration at "high speed" which in this case was 17-18knts. As there was no vibration at lower speeds and the boat is now idling up and down the River Thames this has not been a big concern. Prior to my purchase, the boat had not been used much due to covid; the last change of oil in the gearbox & engine was unclear so I serviced and had various more pressing issues fixed in Jan 23. Now after a full season and a half, I have sent oil samples for engines and gearboxes away for testing. The good news is that the engines both got a clean bill of health however the gearboxes both show signs of wear with Copper, Iron, Lead present in the samples.

From what I can tell there are some parts available for the HS1a, mainly gaskets, pump and the friction/steel disk clutch pack.

So I'm seeking the collective wisdom here, do I:

a) Ignore it for the moment as on the Thames the wear rate is much lower and only worry about it when I plan to take the boat to sea (probably not likely till 26)
b) get a marine engineer to pull the gearboxes and strip/investigate/rebuild (the ones I have spoken to so far don't seem keen on this)
c) remove the gearboxes and send them to an automotive/engineering specialist to strip/investigate/rebuild on the basis that they probably do transmissions much more often than a marine engineer
d) replace the HS1a gearboxes with an alternative transmission e.g. ZF45a which probably adjusting engine height mounting

All ideas welcome at this point!

JM

 

[Plum]

Hi all,

I have a 98 Broom 38 with TAMD41P and the HS1a transmission. I got the boat in Dec 22 and the surveyor noted that there was a noise/vibration at "high speed" which in this case was 17-18knts. As there was no vibration at lower speeds and the boat is now idling up and down the River Thames this has not been a big concern. Prior to my purchase, the boat had not been used much due to covid; the last change of oil in the gearbox & engine was unclear so I serviced and had various more pressing issues fixed in Jan 23. Now after a full season and a half, I have sent oil samples for engines and gearboxes away for testing. The good news is that the engines both got a clean bill of health however the gearboxes both show signs of wear with Copper, Iron, Lead present in the samples.

From what I can tell there are some parts available for the HS1a, mainly gaskets, pump and the friction/steel disk clutch pack.

So I'm seeking the collective wisdom here, do I:

a) Ignore it for the moment as on the Thames the wear rate is much lower and only worry about it when I plan to take the boat to sea (probably not likely till 26)
b) get a marine engineer to pull the gearboxes and strip/investigate/rebuild (the ones I have spoken to so far don't seem keen on this)
c) remove the gearboxes and send them to an automotive/engineering specialist to strip/investigate/rebuild on the basis that they probably do transmissions much more often than a marine engineer
d) replace the HS1a gearboxes with an alternative transmission e.g. ZF45a which probably adjusting engine height mounting

All ideas welcome at this point!

JM

I have a 1999 VP HS1 transmission (also on TAMD41p) still giving excellent service. I have not had an oil sample analysis, luckily! Were the signs of wear consistant with 18 months of use? How do you, or your surveyor, know that the noise/vibration at high speed was coming from the transmission? These transmissions are very over engineered and very robust. If they are working correctly, maybe do nothing and enjoy the boat?

 

[oldgit]

"So I'm seeking the collective wisdom here, do I:"

Some thoughts
How many hours on the engines. ?
a) Ignore it for the moment as on the Thames the wear rate is much lower and only worry about it when I plan to take the boat to sea (probably not likely till 26)
Yes and No.

b) get a marine engineer to pull the gearboxes and strip/investigate/rebuild (the ones I have spoken to so far don't seem keen on this)
lots of money and time doing both boxes ie several thousands per box + lifts including removal and refit especially when one box might be perfectly OK.

c) remove the gearboxes and send them to an automotive/engineering specialist to strip/investigate/rebuild on the basis that they probably do transmissions much more often than a marine engineer .
Doubt you will find any car outfit will touch any marine gearbox and with this amount of money and whats at stake stick with somebody who knows what they are doing and get it right first time.

d) replace the HS1a gearboxes with an alternative transmission e.g. ZF45a which probably adjusting engine height mounting
.......and engines/mounts may need moving (boxes different lengths) + ratios might not be the same ie. repitching props ???? 10K to do this ?


If one of the boxes breaks on the Thames its PITA but gentle drift to the bank and the trudge of shame back to the marina.
Change the oil, use the boat on the Thames, then get the oil tested again prior to going further abroad, aka...kick the can down the road ?

 

[Jon.M]

Trying to summarise:

How do you, or your surveyor, know that the noise/vibration at high speed was coming from the transmission? Good observation - the survey noted that the "slight vibration" was felt above 3000 rpm but that could also be the props needing balanced or a shaft misalignment as well as the transmission.

Were the signs of wear consistent with 18 months of use? I would suggest not, based on the numbers e.g. port Fe ppm = 86, port Cu = 890 however it's also difficult to entirely remove all the oil from these so potentially there was oil in the sample that was a mix of 'fresh' and stuff that had there for 5+ years (based on the state of the filters on the gearbox). A potential source of contamination is also the oil coolers rather than the transmission itself. Taking a good look at the coolers is a lot less invasive than stripping the boxes down.

How many hours on the engines? ~2500hrs on both from what I can tell although one of the tachos was replaced at some point cos it only has 500 hours. Maintenance of the boat to 2019 was very good, with lots of history then she was sold and covid happened so there was a period when she was unable to be used much before I then purchased her. I have no reason to believe that the boat was used extensively in "single engine" mode as she was almost entirely used on the sea rather than inland.

Doubt you will find any car outfit.... I was thinking more of an industrial/machine shop rather than the local garage. I don't know any reputable and local to the boat though to be fair.

d) 10K to do this? - I reckon it will be 10k in parts for both excluding the fitting which as noted will be extensive. The only saving grace is that the gearbox just hangs off the 41p rather than being mounted (from what I remember) so would be able to leave the engines in place.

If one of the boxes breaks on the Thames its PITA but gentle drift to the bank and the trudge of shame back to the marina.
Change the oil, use the boat on the Thames, then get the oil tested again prior to going further abroad, aka...kick the can down the road ?
Yep, this is what I was thinking initially hence it being option a) Should have maybe added keep changing the oil and testing to see what the numbers do on the basis that both transmissions are unlikely to give up at the same time. I'm relatively confident I could avoid the trudge of shame by just running with one engine and the bow thruster - have practiced ;-) as an experiment to see what it's like.

 

[oldgit]

The HS1 is about the same weight and dimensions as the clonky-clunky stone age reverse gear MS4B on my old long gone Princess 35.
MS4B cone drive shaft snapped about week before a long planned cruise.

Nobody was interested in fixing it. Only help came from Volvo Paul with offers of possible bits and advice.

Removal is possible "solo" by any inventive and determined skipper in an hour or two and most of that is simply working out what to undo first..
No need to take boat out of water either, hopefully with only ordinary old fashioned stern glands, merely unbolt flanges and slide shaft back out of the way .

Choice to repair the knackered box or go the whole hog and replace both with a pair of ZF45A , Lancing Marine were doing some good deals at the time.
Investigated both possibilities.
But .............chum had just replaced a destroyed MS4 gearbox in a Princess 33 with a pair of the ZF boxes. It was a expensive time consuming nightmare involving moving engines and and shimming to accomodate different output shaft angle plus plumbing in hydraulics and repitching ????

Busted MS4 parts were available from VP at just over £600 inc P&P, delivered to doorstep within 48 hours.
Bits ordered from Belgium, via Keyparts, arrived following morning, gearbox reassembled by lunchtime, finished work and box refitted that evening.
Cruise started 08.00 the following morning.
VP tacho were/are notorious for the hours LED failing, cheap fix these days with an aftermarket kit available on ebay.

Another MS4 gearbox similar problem.

Both probably caused by props striking something or other.
The later MS5 box , to the casual observer looked to have been beefed up a tad , bigger journals and therefore bearings with larger internal oil channels.
The bits were not interchangable.