Reversing Gears at High Rate of Forward Speed?

You'er right about the big direct units although the last one I saw was on a opposed quad 6-71 with a single output

Ah, sounds like you might be a kindred spirit. Were those engines on one of the small landing craft, an LCI or something like that? I think I know the bearing you mean, it was about 2 feet by 2 feet, had kind of a straddle type mount/sump and a circular inspection port on top?

I used to have a tug with a direct reversible Enterprise that used a Kingsbury GF thrust bearing but that boat was WW2 vintage.

I have a theory for you guys on this one......
We had a guy run over his own anchor line. He got it caught in both props and throttled up to try and get free. When he did that it literally "winched" both shafts together and pulled both struts loose. It actually pulled one up through the bottom of the hull. I got a late night call as the boat was going down quick and we did an emergency haul out and saved it. We still have one propshaft (bent) in the shop that still has that anchor line wound up on it tight as a drum. If your charter customers did this, I can see it causing this damage without a ding on the props. If the struts on the boat were strong enough the engine mounts could be the next weak link in the chain.
Btw, we repaired the boat and it is still running fine.

Not having been there or having looked at the parts, I can't tell you anything other than there is much more to the story than going astern.

And what kind of shift control was used? Was it a Morse cable? What direction did the actuator lever on the gearbox move to select astern?

And who is to say that in the confusion caused by the engine and shaft banging madly around the driver didn't try shifting to see if that would stop whatever was going on?

The position of the gear selector lever is probably the last thing that indicates anything about that incident.

Reversing Gears at High Rate of forward speed

Impresive photos looks like its trying to be a land rover puling something out of a ditch, didnt know the old ford had so much torque, would have thought gearbox would have suffered before mounts

Nothing should have suffered.

Thank God I have the pleasure of Rolls Royce ASD Z drives. I can take my 98 ft Edward J. ***** at full ahead (13 kt) to stop and start astern in the length of the vessel. She shakes an ungodly amount, but when you need it it is a life saver. We have twin EMD 12 cyl. turbo charged. fantastic for the power needed to stop on a dime

This may be the wrong thread but......... can anyone tell me what happened to me today:
1. we were manoeuvring happily from our pier.... port wing station controls (electronic controls back to sender in engine room which drives morse cables to transmission boxes about 2m away) port fwd/starbd reverse to shimmy over.
2. ease port to neutral, and starbd to neutral - starbd does not respond.... we move fwd at 1kn (which seems v quick in tight marina with wharf ahead hoving into view). Intermittent alarm sound at port station.
3. toggle starbd control back to reverse, back to neutral. no response.
4. proceed quietly (!) to the bridge , press 'come to me' button, wait precious seconds for controls to come to bridge throttle station,... arrest fwd mvmt (just in time to save their wharf and our dignity..... ahem)
5. bridge controls worked fine
6. repeat performance end of day.... when starbd engine actually shut down to stop fwd motion (berth on port engine and bow thruster - fun). Bridge throttle control alarm sound.
7. problem solve:
- morse cables driving selector OK
- no morse cable damage
- all throttle stations (5) tested - apparently gears selected OK (couldnt tell as engines off)
- cable tension seemed OK (but may have been a little tight - so loosened off a bit)
- next day repeat checks - this time engines on) - all OK.

We're running ZF Mathers Controls Micro Commanders (and of course ZF transmissions)

Now, I never mind an absence of system failure. I love that. But when I have one (apparently) and I can't find/prove the problem later.... I hate that.

Your thoughts?
- user error (if so what) ?
- what would cause the alarm to sound: is it saying "Warning: no comms here" or is it saying "Warning: the gear lever has moved but the transmission has not responded as you directed"... or something else.

Thank you all in advance
Campbell

The alarm confuses me. However, taking that out of the equation for a moment (before calling in the service person) I'd first check that the control handle isn't slipping. Had that happen to me last year with manual controls. My mind went everywhere, and I felt like a fool when the tech came aboard and immediately found it to be the set screw backed out. The second thing I'd check is that the cable is secured before the linkage. A few times I've had them jump out of the clip, and learned to cable-tie them in place. When out of the clip sometimes they work and sometimes they don't.

Now back to the alarm. That leads me to what Capt. Bill surmised, and it's beyond my capabilities to diagnose. So if not one of what I mentioned, I'd call in the tech as it sounds like an electronic error.

Change the control head. The zf mathers micro commander controls are not very susceptible to a wet location and they usually fail intermittently like that, then start doing it more often. The control head is not that expensive $700 maybe and can be changed pretty easily. The fact you're getting an intermittent alarm there tells me it's an issue with the station. The only other thing it could be, would be the wiring connections and when you pull the control head out, you'll be able to inspect them, as micro commanders utilize very small wires.