Hydraulic vs mechanical gearbox.

[Uncle Bob]

Originally Posted by sailorxyz

I think Hurth boxes get a lot of bad rap because people put undersized boxes in. I've had a Hurth HBW150 for over 20 years in LC (my old boat) and it never gave problems of any sort. I changed the ATF at the recommended intervals but nothing else. It's coupled to a 36hp Mitsubishi conversion that likewise has never given problems.

You have done well, the same box in my boat lasted around 860 hrs, behind a 50 hp Kubota.

Originally Posted by Visarend

I have a very good experience with a hydraulic PRM 120, on my Ford 48 HP since 30 years. lots of motoring in the Med in summer, sometimes for 5-6 days at a time. This year it lost the oil, which became apparent only controlling the bilge, it still went on, with no need to operate the mechanical take me home trick. The oil leak is due only to a seal, but it is probably the moment for remotorising the boat.

The PRM 120 is what I replaced the hurth with, but I do believe that it is a "simple mechanical gearbox" not a hydraulic box.

[GILow]

Reading all this, I really think I will go mechanical.

I just checked and the Beta comes with a TMC60 mechanical box as standard so I’d appreciate people’s opinions on that combo.

[Wotname]

Perhaps I have missed it upthread but what sort of gearbox do you currently have and are you happy with it?

[GILow]

Originally Posted by Wotname

Perhaps I have missed it upthread but what sort of gearbox do you currently have and are you happy with it?

Currently I have a Velvetdrive 71C. It was a good box but it has a couple of problems.

The first is age. It has freewheeled over 42,000 miles of the South Pacific so the rear bearing is noisy. And those rear bearings are not cheap. Apparently they can go that way forever, but I don’t like it.

It also has over 2000 hours use, unless the engine clocked up a lot of battery charging time, which I doubt. I don’t know how many hours those boxes are good for, but it has to be at least suspect now.

The second problem is the ratio. It’s a 1.5:1 box which was fine for my old Nissan which I run at 1200 rpm or less, but the smaller engines need more revs.

So I’ll flog it off with the engine as a going cheap package. It will all serve someone well enough.

Maybe a 25 foot river boat could use it?

[Wotname]

Originally Posted by GILow

.........

So I’ll flog it off with the engine as a going cheap package. It will all serve someone well enough.

Maybe a 25 foot river boat could use it?

Haha, I'll keep a sharp eye on the local dumpsters then

[GILow]

Originally Posted by Wotname

Haha, I'll keep a sharp eye on the local dumpsters then

Harsh.

But probably realistic.

[Visarend]

Originally Posted by Uncle Bob

You have done well, the same box in my boat lasted around 860 hrs, behind a 50 hp Kubota.



The PRM 120 is what I replaced the hurth with, but I do believe that it is a "simple mechanical gearbox" not a hydraulic box.

Uncle Bob, you are absolutely right. I misquoted the model, it's a PRM 150 - my fault.