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Old 24-09-2012, 00:51   #1
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Full reverse from full ahead!

I read that one problem with chartering out your boat is that the inexperienced charterer often panics into slamming into reverse before the prop stops. Surely this is a simple thing to prevent -same as putting a governor on the accelerator?
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Old 24-09-2012, 01:38   #2
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Re: Full reverse from full ahead!

There are a host of boat abuse issues that can happen to your boat when it's in the charter fleet; sort of the nature of the beast. I'm not an engine guy but the torque on most diesels seems pretty wimpy. I know it's not a good idea to slam the gears back and forth but it happens all the time and I don't see a ton of people having issues.

Just my $0.02.
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Old 24-09-2012, 01:57   #3
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Re: Full reverse from full ahead!

With modern hydraulic 'boxes, not a problem. The clutches in the 'box will absorb the reverse direct of rotation.

Mechanical boxes are another matter altogether! The prop & shaft must be slowed down or there will be tears and a 'box full of bits!

Having said that, I would not recommend full ahead to full reverse on a regular basis it will just wear all the 'box internals rapidly.
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Old 24-09-2012, 02:10   #4
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Re: Full reverse from full ahead!

Also I find giving a pause between forward and reverse means less likelihood of prop cavitation (which of course means that reverse might actually stop forward motion!).

Although I suspect that if starting from Full Ahead then less likelihood of that! (albeit have never tried).
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Old 24-09-2012, 07:30   #5
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Re: Full reverse from full ahead!

This is a bigger issue with separate throttle and shifter controls. Most modern boats have a single lever, so the rev's are dropped when shifting. Still a short pause in neutral does seem beneficial.
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Old 24-09-2012, 08:07   #6
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Re: Full reverse from full ahead!

The cone clutches in my Kanzaki v-drive allow emergency reversal at full throttle without damage. At least that's what the book says. I'll wait till that feature is needed before trying it.
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Old 24-09-2012, 08:12   #7
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Re: Full reverse from full ahead!

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Originally Posted by 40 South View Post
With modern hydraulic 'boxes, not a problem. The clutches in the 'box will absorb the reverse direct of rotation.

Mechanical boxes are another matter altogether! The prop & shaft must be slowed down or there will be tears and a 'box full of bits!

Having said that, I would not recommend full ahead to full reverse on a regular basis it will just wear all the 'box internals rapidly.
On my Velvetdrive (hydraulic) it is a BIG problem...there is a damper plate that bolts to the flywheel...its center is splined to receive the trans shaft, when shifting from forward to reverse with out suitable time for revs to slow the FM splines sheared.
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Old 24-09-2012, 08:18   #8
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Re: Full reverse from full ahead!

Some systems that are electronically controlled allow for this with no damage. I have a TwinDisc controller that allows for it.

I have not had a need for it nor tried it. It's a scarry thought to try it on a 20 knot boat.
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Old 24-09-2012, 14:15   #9
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Re: Full reverse from full ahead!

FWIW, the manual for my ZF10 tranny SAYS that this practice is ok... but one would be a fool to do it routinely.

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Old 24-09-2012, 15:12   #10
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Re: Full reverse from full ahead!

Inertia is the reason . Shock loads are not good for any drive system.
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Old 24-09-2012, 15:39   #11
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Re: Full reverse from full ahead!

The tranny may take a Power Shift ! BUT Ive seen to many broken prop shafts from this bad habit ! And a couple of props snapped off also! I guess if ya mess up and need to do it to keep from doing major damage to your or others boats then maybe ya can do it ! But remember damage can happen ! just my 2 cents
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Old 24-09-2012, 15:56   #12
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Re: Full reverse from full ahead!

IF ya never use full ahead, you'll never need full astern. Theres a saying here, "when boating, sh12 happens, all you can do is make it happen slowly"
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Old 24-09-2012, 23:08   #13
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Re: Full reverse from full ahead!

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IF ya never use full ahead, you'll never need full astern. Theres a saying here, "when boating, sh12 happens, all you can do is make it happen slowly"
Teaching ASA classes we say "only go as fast as you can afford the repair bills"
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Old 02-10-2012, 08:07   #14
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Re: Full reverse from full ahead!

For those of you who have V-Drives...the hydraulic transmission might take a slam from forward to reverse...but your v-drive (tough as it may be) is something else.
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Old 02-10-2012, 08:18   #15
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Re: Full reverse from full ahead!

That's only one of a million issues I'd be concerned with having others charter my boat..Flooding the head and sinking the boat would be MY number 1 issue...
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