To all those gearheads out there. I posted about two months ago about a gear slippage problem we have on our new Southerly 42RST with a Yanmar 4JH5E. (Our dream boat after 40 years of sailing - including co-skippering 20 Chicago to Mac races and cruising a 52 footer in the BVI multiple times.) Recap .... In one occurrance the engine would not shift into forward when we were slowly backing out of a rafting situation. In the other two occurrances the engine would not shift into reverse coming into dock. In the final occurrance reverse was totally lost - the builder's mechanic was on site and had to make adjustments to the cable in order to acheive reverse. This is an intermittant problem - 3 occurrances in 17 dockings. We left England (where our boat will remain for a year) thinking the company would contact Yanmar and check out the engine transmission, instead the company is claiming that the shifting problems are operator error. The boat sails beautifully but until there is a reason for the gear-slippage I am hesitant to take it out again. Any thoughts?
Taurus - To all gearheads
- Thread starter Taurus
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Captain, you are simply going to have to go down below and inspect your transmission linkage and assure yourself that the shifter is positively engaging reverse, neutral, and forward. What you describe is not "gear slippage" it is a failure to engage your selected gear. You are jumping to a big conclusion to assume that your transmission is "slipping". You will need an assistant at the helm to work the teleflex shifter. You should also be looking for nearby hoses, wires, and engine room peripherals that can jam the shifter. There are a lot of operator errors that can make these complex engine controls misbehave. One of the worst things you can do is force the linkage in a panic. If you can effect a shift at the transmission, when the helm is jammed, you have your answer - the teleflex or helmsman is the problem. Anyway, it isn't a reason not to sail the boat, you can always put someone below to free the linkage should it jam. Not a long term fix, but beats not using the boat.
If it's new, and the control is in fact properly adjusted, which is a simple an adjustment as can possibly be, it can be nothing but defective. 42 year sailor doesn't know how to push a lever forward or back? Lawyer up. A letter on expensive engraved stationary might wake them up.
I recently posted an inquiry to "all gearheads" who might have some input on the gear-shifting problems we have been having with the Yanmar engine on our new Southerly 42RST. The post implied that the company who built the boat was not responding to our requests to thoroughly evaluate the problem. I would like to say that I should have waited on the post for the company has responded with an aggressive plan of action that is befitting the excellent customer service we experienced in the design and build phase. We look forward to working collaboratively with the Southerly builder and Yanmar in solving the problem.
Feathering Prop Not Feathering?????
It is difficult to imagine how a gearbox could go into reverse smoothly most times but suddenly fail to do so on other occasions. Then, just to be perverse , to not go into ahead when shifting from reverse
However I can visualise such a situation if you have a feathering prop such as Maxprop or similar.
When a featherer goes from ahead to astern the blades rotate on their axis by approximately 180º. This is achieved by some gearing inside the prop hub. If there was anything loose inside this gearbox such as a nut or other foreign body, chunk of gear tooth etc, then it is quite possible for it to only allow the blades to turn through a limited angle then jam. If the blades rotated anywhere more than say 45º but less then 135º then, though the prop shaft changed direction of rotation correctly into the right direction, i.e. the engine's gearbox had reversed, the prop blades would, in effect produce thrust in the same direction as before so there would be NO REVERSAL OF THRUST.
If it were my boat I would take a look inside the prop hub.
Another condition where this might occur is if there is anything external round a blade that would stop it rotating the required 180º. A maxprop has a long hub and it would be easy for a loose piece of wire to create this condition.
PS:- If I an right in my assumption I would sure like to hear because I too have a featherer.
It is difficult to imagine how a gearbox could go into reverse smoothly most times but suddenly fail to do so on other occasions. Then, just to be perverse , to not go into ahead when shifting from reverse
However I can visualise such a situation if you have a feathering prop such as Maxprop or similar.
When a featherer goes from ahead to astern the blades rotate on their axis by approximately 180º. This is achieved by some gearing inside the prop hub. If there was anything loose inside this gearbox such as a nut or other foreign body, chunk of gear tooth etc, then it is quite possible for it to only allow the blades to turn through a limited angle then jam. If the blades rotated anywhere more than say 45º but less then 135º then, though the prop shaft changed direction of rotation correctly into the right direction, i.e. the engine's gearbox had reversed, the prop blades would, in effect produce thrust in the same direction as before so there would be NO REVERSAL OF THRUST.
If it were my boat I would take a look inside the prop hub.
Another condition where this might occur is if there is anything external round a blade that would stop it rotating the required 180º. A maxprop has a long hub and it would be easy for a loose piece of wire to create this condition.
PS:- If I an right in my assumption I would sure like to hear because I too have a featherer.
Single lever control
If that has a single lever control, may very well be the neutral button not releasing. Ran into this recently on a friends boat. A little squirt of WD40 fixed the problem.
If that has a single lever control, may very well be the neutral button not releasing. Ran into this recently on a friends boat. A little squirt of WD40 fixed the problem.
If a mechanic has been able to mess with the linkage to get it to shift, then its likely not the propeller.
As stated above, disconnect the controls at the transmission, and have someone shift the transmission manually while someone is controlling power at the helm. If it works okay, something in the controls is amiss. Those transmissions are pretty simple, they kind of either work or they dont, nothing to slip really.
By operator error they may not necessarily mean the boat operator, so much as the controls. Though one would think they would choose their words more carefully.
As stated above, disconnect the controls at the transmission, and have someone shift the transmission manually while someone is controlling power at the helm. If it works okay, something in the controls is amiss. Those transmissions are pretty simple, they kind of either work or they dont, nothing to slip really.
By operator error they may not necessarily mean the boat operator, so much as the controls. Though one would think they would choose their words more carefully.
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