Towing and Shaft Brake

[GoldenDawn]

I have to tow my Kadey Krogen 42 later today and not having done this, am wondering if I will need to brake the shaft? The transmission is a "Velvet Drive" on the Ford Lehman 135.

And am guessing that the issue is overheating the transmission fluid? Our tow is estimated to take 2hr @ 5 knots and I can monitor the transmission temperature.

Why am I asking the Forum? I am having trouble reaching my regular mechanic.

 

[Jetstream]

From all I can find your Velvet Drives will be fine as long as you stay below 7 to 8 knots. I'd keep an eye on the temp but don't think you'll have any problems.

 

[North Baltic sea]

Switch into forward gear, the shaft does not rotate, and lau does not have to worry about grease or high temperature.

 

[cafesport]

Water temp up that way is probably cold enough not to worry but you should monitor the shaft log temp in case you can't lock the shaft down.

 

[koliver]

John:

I too have Velvet Drives. When this boat was new to me, I had deadhead damage to one prop, so did the rest of that trip, 50 hrs or so, on one. At the time, I checked, as you are doing, and was advised that VDs could take it. So far that has been the case. As other have advised, in cool waters, in fwd gear, there will be no warming of the transmission as long as you keep your speed below planing.

More recently, I had one engine down for the whole summer, so I put a pipe wrench on the shaft to act as a brake. I left the wrench a couple of inches away from engaging the stringer and found that my maximum speed on one engine of about 6.5 knots wasn't enough to turn the shaft and engage the wrench.

 

[Capt.Bill11]

Switch into forward gear, the shaft does not rotate, and lau does not have to worry about grease or high temperature.

No, the shaft will rotate.

 

[High Wire]

No need to lock per BW manual.
Even if you did, don't put a pipe wrench on the shaft. Put it on the COUPLER if possible.

 

[GoldenDawn]

I am going to have a pipe wrench ready. I found an online Velvet Manual and it also advised that for slow speeds, a brake is not necessary.

Thanks for giving me help on this early in the morning. Off to Sidney we go at 11:00.

 

[waddenkruiser]

No, the shaft will rotate.

Definitely because there isn't any hydraulic pressure to close the clutch as long as the input shaft (from engine) does not rotate. The gear output shaft will rotate as well as all gearing aft the clutch.

I would leave the gear in neutral. There won't be any significant load on the gear so I can't imagine that the gear itself would be harmed even if you would tow much longer with slow speed. All I would do is to check the ATF after the tow and change it if necessary.

 

[Ken E.]

I have to tow my Kadey Krogen 42 later today and not having done this, am wondering if I will need to brake the shaft? The transmission is a "Velvet Drive" on the Ford Lehman 135.

And am guessing that the issue is overheating the transmission fluid? Our tow is estimated to take 2hr @ 5 knots and I can monitor the transmission temperature.

Why am I asking the Forum? I am having trouble reaching my regular mechanic.

You might check your gear's website, Borg Warner I think, for what they say about towing. It should be in the owners manual. The Alison gears I've had in the past forbid it, but my current Twin Disc gears allow the props to be freewheeled, checking the temp periodically. Since you're being towed, your engine is inop (?) If you can start the engine, it will also cool the gear down. But for your 2 hour trip at 5 kts, you likely need not be too concerned.

 

[kelbylinn]

Careful with pipe wrench. If you score the shaft and have to remove it, it could mess up your packless shaft seal.

 

[C lectric]

Switch into forward gear, the shaft does not rotate, and lau does not have to worry about grease or high temperature.

Sorry but that advice is incorrect. The Velvet drive is a hydraulic gear and without the hydraulic pump being run by the engine there is NO PRESSURE to do anything. A hydraulic gear WILL NOT LOCK THE PROPELLOR SHAFT by putting the shift lever in gear.


You would be correct with a mechanical gear such as many Hurths

 

[Brisyboy]

Just a thought about free wheeling -what happened if you have a water cooled dripless prop shaft seal?

With no engine, no cooling water, but a prop spinning at maybe half rpm. A problem?

 

[Capt.Bill11]

Just a thought about free wheeling -what happened if you have a water cooled dripless prop shaft seal?

With no engine, no cooling water, but a prop spinning at maybe half rpm. A problem?

That's why you should have a valved cross over water feed line between the two shaft seals that you can open to feed the seal on the free wheeling shaft from the running engine.

 

[Brisyboy]

That's why you should have a valved cross over water feed line between the two shaft seals that you can open to feed the seal on the free wheeling shaft from the running engine.

Ahh Ha .. good thinking 99

 

[cafesport]

Bill, I'm guessing this owner has single engine 42 because a twin wouldn't need a tow. In 40 degree water even a 50 degree rise in shaft log temp wouldn't be a problem and the velvet drive just won't care windmilling at 5 knots for two hours. For those who do need to use a shaft brake from time to time, a pair of 2x4's clamps, cable ties, marlin, even hose clamps can will prevent all kinds of problems.

 

[psneeld]

You would be very surprised at how many twin engine boats I have towed for all kinds of reasons.

On older Sea Ray's before the crossover tubing, we would just pull the hose and let it trickle into the bilge to keep a flow going. Even a tiny bilge pump easily kept up. Not the best solution, but in a pinch.

 

[AKDoug]

The shaft seal is a major point, if it's dripless and the engine isn't running it's not lubricating the seal. I towed a NT 32 and the dripless started squealing so we wound up locking the shaft with a pipe wrench wrapped in rags on the coupler. I would imagine the transmission also uses the engine running to provide lubrication flow...

 

[GoldenDawn]

Just as a post script, the tow went well. I was able to reach the mechanic before starting and he confirmed that a shaft break was not needed. Tow was most at 6 knots. Outside and water temperatures were in the 40s and the transmission never warmed above 95F (normal running temp is 130-140F). I have an old fashioned stuffing box so no issues with dripless seal; the box never got above 50F.

Here's a photo of the last bit of the tow - kind of close quarters, crew on the front deck helping with pike poles. The little tug had a 7hp Yanmar.