Tranny question

[bayhoss]

I have a 1986 E28 with a Hurth transmission. I've often wondered if it could do any possible harm to the trans. to have the engine running with the trans in neutral while sailing.

Best always,
Frank

 

[Rocinante33]

For a short time, I don't think it would do any harm. But for a longer period, it seems to be the input shaft on the Hurth which provides the lubrication - circulation. Not sure if that will happen when out of gear, or not. Probably OK, but I wouldn't run like that for too long, just in case the lubricity is not adequate.

 

[mherrcat]

Sailing in neutral will cause the prop and shaft to rotate. Just wonder if that would cause any problem. When I shut down the engine I always put the trans in reverse for sailing. Adds more drag with my three-blade prop, but I am not concerned; figure it's less wear on the cutless bearing and stuffing box. I don't like the prop freewheeling when I am sailing.

 

[MarkA]

What model?--the 50?

I've read Hurth materials that say it's fine to sail in neutral or reverse. NEVER forward. I don't have time to dig them up now, but Google will lead you to several threads on other forums where people have linked to to, or quoted, the Hurth instructions.

 

[mherrcat]

It is true that the operating instructions mention leaving the transmission in neutral or reverse when sailing, but I don't think there was any mention of sailing with the engine running and the transmission in neutral.

 

[rwthomas1]

I would have to ask, if the engine is running, why would you not have it in gear? I'm guessing you are charging batteries, etc. while under sail? This uses little of the available HP so putting it in gear is actually better for the engine. Diesels are happier running under a load. RT

 

[MarkA]

So we know:1. We can idle the motor in neutral; and, 2. We can sail in neutral. Why no both? Either way, we have one end moving independantly of the other end.

 

[Loren Beach]

I would have to ask, if the engine is running, why would you not have it in gear? I'm guessing you are charging batteries, etc. while under sail? This uses little of the available HP so putting it in gear is actually better for the engine. Diesels are happier running under a load. RT

That reminds me that ocean racing boats often run their engines in neutral to charge batteries for several hours a day, or at least some of them do.
They have water makers, AP, computers, HF and Sat radios, and networks of nav instruments to power...

Perhaps there is no harm to the transmission.


LB

 

[rwthomas1]

That reminds me that ocean racing boats often run their engines in neutral to charge batteries for several hours a day, or at least some of them do.
They have water makers, AP, computers, HF and Sat radios, and networks of nav instruments to power...

Perhaps there is no harm to the transmission.


LB

I suspect that the "slinger" in the trans that flings the oil around for lubrication is integral to the input shaft. This would make sense as it would function in neutral or any gear. It would not function when the output shaft alone is turning, such as sailing with an unlocked prop. That would explain the Hurth recommendations. RT

 

[bayhoss]

Thanks to all for the excellent answers. The area that I sail in can be crab pot central. So I frequently have the engine running to bring up the charge on the batteries and in case I need to avoid another vessel on approach. More the second of the two. But, like I said it's loaded with crab pots so I sometimes just shift into neutral so that I don't tangle a line in the prop and sail along with the engine at an idle.

Thanks for the input!
Frank

 

[clp]

I couldn't tell you about the gearbox per-say, but I have run diesels for a week at a time without ever shutting it down. And have idled it for 48 hours or more. If you don't run most diesels for an hour or more, every time it's cranked, you're killing it. A hot diesel, is a happy diesel.

 

[Gumdoc]

I was unsure whether, while sailing, what selection to have my transmission in, with the engine off. I have a Universal M3-20B with a Hurth transmission. I came upon this in the E-32 owner's manual:

"To prevent excess wear on the transmission, shaft and strut bearing, and also to reduce drag for more efficient sailing, be sure to place the transmission in reverse after the engine has been shut down while sailing. Note: Leaving the transmission in the “Forward” position while sailing after shutting down the engine will “glaze” the transmission plates and cause slippage when the engine is running in gear."

Then I searched for a thread on the issue. From what I read in this thread it appears that sailing with engine off and the selector in neutral, the prop will be spinning but the shaft will not be lubricated as it should be. This is significant and confirms the preceding paragraph. I have been told that if the transmission is in reverse and the engine is started, real damage will occur. I've gotten in the habit of making sure I am not in reverse when I start, but if I always sail in reverse, I am concerned that someday, in an emergency, I may make a mistake and not check. Will starting in reverse do damage and to what? Thanks

 

[Loren Beach]

Ommmmmmmmm

Over the years I have accidently started in reverse a time or two. No harm that I'm aware of. We were out sailing, had a good thrash, and got a little distracted/hurried in getting the diesel going.
(Universal M25XP with Hurth trans.)

Using a sort of 'mantra' of "shift in neutral, half throttle, switch on, glow for a 10 count" and hit the starter button.
Never a problem, but then I like having a memorized procedure for this stuff...

And then always, as soon as it fires, look over the transom for water coming out the exhaust.


Loren

 

[eknebel]

watch your angle of heel

Something to remember is that there is a limit to how much heel can occur before the engine loses oil pressure because the oil in the crankcase is no longer submerging the oil pickuptube for the oil pump. On the Universal 5416 it is 15 degrees, I imagine most other models are similar. I have a inclinometer on the binacle that is in the view of the helmsman, with red on the markings after 15 degrees. It is reassuring to look at when you are using the engine and sails at the same time.

 

[Maine Sail]

"To prevent excess wear on the transmission, shaft and strut bearing, and also to reduce drag for more efficient sailing, be sure to place the transmission in reverse after the engine has been shut down while sailing. Note: Leaving the transmission in the “Forward” position while sailing after shutting down the engine will “glaze” the transmission plates and cause slippage when the engine is running in gear."

The manual is incorrect on "more efficient" sailing with a locked fixed blade prop. With the typical fixed props shipped on these boats there is considerably less drag when they are freewheeling.

They are 100% correct that leaving it in forward is BAD. These Hurth/ZF boxes CAN be sailed in either neutral or locked in reverse but never left in the same direction of travel eg: forward.. By free spinning you are adding more wear to the cutlass, packing and gear box seals but they can go thousands of hours this way. I would easily guess that way more cutlass bearings are destroyed by bad alignments than by a properly aligned boat free spinning while sailing.

Then I searched for a thread on the issue. From what I read in this thread it appears that sailing with engine off and the selector in neutral, the prop will be spinning but the shaft will not be lubricated as it should be.

Absolutely untrue with the Hurth/ZF boxes on Universal Diesels. The Hurth/ZF boxes are splash lubed and do not need the engine running for lubrication.

I have been told that if the transmission is in reverse and the engine is started, real damage will occur. Will starting in reverse do damage and to what?

It puts a larger in-rush on the starter and if your dinghy painter is behind you then yep real damage... Other than that it causes little harm just don't do it every time...

From the Universal Engines Manual:


From Universal:

UNIVERSAL DIESEL WITH HURTH TRANSMISSION

Model HBW-50 (2:1)
Used on Models 12, M2-12, M-18, M3-20, M4-30, M25 and M-25XP

Model HBW-100 (1.8:1)
Used on Models 30, 35, and 40

Model HBW-150 (1.9:1)
Used on Model 50

Model HBW-150 V-Drive (2.13:1)
Used on All of our V-Drive Models

CAUTION
DO NOT LEAVE GEAR IN FORWARD WHEN SAILING. GEAR MUST BE IN NEUTRAL FOR FREE WHEELING OR SHIFTED INTO REVERSE TO LOCK PROPELLER WHILE SAILING

 

[Gumdoc]

Thank you all for your input. Great information and referenced to boot. John