What could have happened?... Transmission?...

[gevac5]

I encountered this same problem several times and each time it was the result of fouled Max props!!! They would behave exactly as you described. The blades won't pivot for the pitch to change from reverse to forward. Try cleaning them, look for line, weeds, or growth on the hub where the blades attach. Barring that the prop may need to be disassembled and relubricated.
Look on line at Max Prop for more information. Folding props are the cause of your problem. You can test this by fixing the props then deliberately fouling them with a line. It will duplicate your experience. You'll need to get in mask and snorkel or ask someone to clean the prop off (hull cleaner service)
I would like to hear from you when you find out I was right!
Yours:
georgedavis1@mac.com

[sailorladd]

What comes to mind first of all is, What kind of gear box? If is an hydraulic gear box, could you be low in oil?? just a thought...

[Benetoe]

you have a WORN trust washer

it only take a 'few thou of an inch' to go this way.

take gearbox out & you have to get them to put in a new one-

i happened to me exactly as you describe....

[Juggerknot]

My money is on the fouled prop theory. I experienced similar behavior that turned out to be a plastic bag I must have picked up reversing at the dock. Long and short of it, maxprop couldn't transition to forward pitch. !0 minutes in mask and snorkel and she was good to go. Take a peek if you're able, may be something as simple and if not, at least you can rule it out.

[Benetoe]

its been 9 yrs since orig post

what was the cause

[billknny]

I have had EXACTLY that happen with a rope fouled around a maxprop. Normal reverse, no forward! In my case it took a dive to remove the rope. The story of our similar encounter with submerged debris:

http://fetchinketch.net/2015/12/03/surprise-surprise

Having said that... it certainly CAN be your transmission slipping in forward but not reverse. It certainly does happen.

Check carefully the adjustment of the shift cable, it could be as simple as not fully engaging in forward. Or it could be slipping clutches, and need a rebuild.

[Jim Cate]

Originally Posted by Benetoe

its been 9 yrs since orig post

what was the cause

Looks like a week to me... maybe you forgot to wind your calendar!

Jim

[StuM]

Originally Posted by Benetoe

its been 9 yrs days since orig post

what was the cause

There, fixed it for you.

[RaymondR]

Originally Posted by Benetoe

you have a WORN trust washer

it only take a 'few thou of an inch' to go this way.

take gearbox out & you have to get them to put in a new one-

i happened to me exactly as you describe....

If it's a groove worn in the thrust washer you can turn them around to fix the problem.

[FabioC]

Thank you for all the opinions and suggestions.

I had a diver have a look and service the Max Prop. He found some barnacles, but not much, so we are still not 100% sure of what happened... He services the Max Props at my marina, and said that it does not take much growth to prevent the blades from setting correctly, so we do not know for sure.

Also, if you remember, when the event happened, forward came back at the very end, so it is entirely possible that there was something stuck on the prop that eventually got freed up and allowed the blades to finally set.

I went out and tested the boat, and forward/reverse now both work beautifully. I had a mechanic to have a quick look at transmission and gear box as well, but at least when he was looking at them, they seemed to be working well.

So, there is no certainty of what happened, which spooks me a bit because it was a very tense situation to be in the fairway without forward and I do not want to repeat it, but the Max Prop blades not setting is still the most likely explanation...

The lesson learned from this is that there is a chance that the Max Prop does not set correctly (I had not thought of that before this happened). Regardless of whether it was the culprit in this particular event, the consensus from the people servicing it, is that the MaxProp itself is very reliable, but it is a highly-precise piece of equipment, so any impediment in the mechanism can have quite an effect on the blades not setting properly. Thus, in the future, I am going to keep an eye at the growth on the prop (I'll use my GoPro to take an underwater picture every 2 or 3 weeks).

Most importantly, I think it is a good idea to test forward/reverse at the dock before casting the lines, as part of the routine of leaving the dock. If you have a Max Prop, it is something to consider.

[FabioC]

Originally Posted by Jim Cate

If a shaft drive, visual observation of the shaft whilst in fwd gear and not moving properly will show whether it is prop malfunction or slippage in the tranny.
Jim

Hi Jim,
Can you elaborate on this? From visual observation of the shaft drive, how exactly would you point out an issue with the prop?
Specifically, since the most likely explanation for this event turned out to be the Max Prop not setting correctly in forward, would there be any visual clue of that happening by looking at the shaft? Or, is it as simple as: if the shaft is spinning normally, it must be the prop?
Thank you!

[StuM]

Originally Posted by FabioC

Or, is it as simple as: if the shaft is spinning normally, it must be the prop?
Thank you!

Yep, it is that simple.

[waterman46]

Originally Posted by FabioC

Hi Jim,
Can you elaborate on this? From visual observation of the shaft drive, how exactly would you point out an issue with the prop?
Specifically, since the most likely explanation for this event turned out to be the Max Prop not setting correctly in forward, would there be any visual clue of that happening by looking at the shaft? Or, is it as simple as: if the shaft is spinning normally, it must be the prop?
Thank you!

If shaft is spinning as commanded at helm (both direction and RPM), then problem is the prop. BTW I have an AutoStream feathering prop (made in Australia). After our boat sat at anchor in La Paz for four months, we returned to it and the AutoStream worked flawlessly right from the start. Later I dived on the boat to clean the bottom - there were about a dozen barnacles as big as my thumb (no kidding) on that prop, plus a lot of mossy growth. None of that stopped the AutoStream from functioning normally in forward and reverse.

Previous haulout we should have painted the prop and shaft, but that wasn't done by the yard and I didn't notice it before launching. Apparently those monster barnacles like to attach to stainless steel.

[Jim Cate]

Originally Posted by waterman46

If shaft is spinning as commanded at helm (both direction and RPM), then problem is the prop. BTW I have an AutoStream feathering prop (made in Australia). After our boat sat at anchor in La Paz for four months, we returned to it and the AutoStream worked flawlessly right from the start. Later I dived on the boat to clean the bottom - there were about a dozen barnacles as big as my thumb (no kidding) on that prop, plus a lot of mossy growth. None of that stopped the AutoStream from functioning normally in forward and reverse.

Previous haulout we should have painted the prop and shaft, but that wasn't done by the yard and I didn't notice it before launching. Apparently those monster barnacles like to attach to stainless steel.

Interesting observation!

We too had an AutoStream prop on our previous boat, and had similar experiences... they just continue to feather despite fouling. And ours had around 4000 hours on it when we sold the boat, and there was no perceptible wear on bearings, stops or gears.

I know that Max Prop has an almost cult-like following in the States, but I see CF members saying that they need factory refurbishing on a regular basis and they have feathering issues as noted here, and they are more expensive than the AutoStream... makes you wonder!

Jim

[Jim Cate]

Originally Posted by FabioC

Hi Jim,
Can you elaborate on this? From visual observation of the shaft drive, how exactly would you point out an issue with the prop?
Specifically, since the most likely explanation for this event turned out to be the Max Prop not setting correctly in forward, would there be any visual clue of that happening by looking at the shaft? Or, is it as simple as: if the shaft is spinning normally, it must be the prop?
Thank you!

Yes, as several others have already posted, that is the case. If there was enough slippage in the transmission to keep the boat from moving, the shaft would be stopped or nearly stopped, and that would be pretty obvious to an observer. If the shaft is spinning normally and the boat isn't moving, there must be some fault in the prop.

It sounds like you have found the culprit, and it was easy to fix, so happy days for you!

Jim