Is it My Stuffing Box?

[cmesiam]

Lost propulsion last weekend and thought I lost the Prop. Prop is still attached to shaft but entire prop and shaft slide in and out (rddr kept it from falling all of the way out). Is that the stuffing box? Yes, I've read the other post about stuffing box and how to do it. I'm still not sure that is my problem?
I have a 'clamp' with two screws. I didnt take it off yet, but intend to later this weekend. Has my shaft slide out of the stuffing box because it was worn out? If I repack will it stay?

Any info would be helpful at this point? Thanks in advance.

Bruce
bruce.hansen@navy.mil or cmesiam@aol.com

[Sailabel]

Hi Bruce.... no, probably not the stuffing box. The stuffing box is the 'water-tight' (not really watertight, but you know what I mean) seal where the prop-shaft exits the hull. The end of the shaft is usually attached to the transmission with a coupling. My guess is that the bolts that hold the shaft into the coupling have come loose, allowing the entire shaft/prop to slide back. The shaft (at least on my boat) is held tight in the coupling with two 'set bolts': bolts that have a pointed end and are run in tight against the shaft to hold it in place. As a side note, the shaft is also 'keyed' in position so it can't rotate. The 'set bolts' should then be wired so they can't come loose.

To check, climb in to where the shaft meets the transmission.... I'll bet that the whole shaft just came loose at the coupling.

If so, repacking the stuffing box won't have any effect. The good news is that this isn't really uncommon and is an easy fix while still in the water.

[karlhead]

Sailable is correct. There should be an indent on the shaft where the two bolts that go thru the coupling are located. What may have happened is one or both of the coupling bolts loosened and allowed the key to fall out of the keyway on the shaft. Its probably in the sump under the coupling.

[karlhead]

I forgot........the 2 bolts on split flange coupling are supposed bo safety wired to prevent this exact th;i;ng from happening again.

[cmesiam]

All,

OK, I'm going to look at that connection. I will head out there tonight and have a look.

Do any of you know about a grease fitting on the (what I believe) is the stuffing box?

Thanks for all,
Bruce

[Rex Delay]

The stuffing box is lubricated by leaking a little water when turning. After you fix your coupler, run the engine in gear and observe the box. It should drip about twice a minute. If not, tighten or loosen it accordingly. If excessive drip, you need to re-pack. A simple job but has to be done out of the water.

[Stevens 47]

The 'set bolts' should then be wired so they can't come loose.

A better practice is to drill through the shaft at one of the set bolts and insert a bolt all of the way through the shaft and the flange. Do this after you have inserted the key and the other set bolt.

[S&S]

Originally Posted by Stevens 47

A better practice is to drill through the shaft at one of the set bolts and insert a bolt all of the way through the shaft and the flange. Do this after you have inserted the key and the other set bolt.

Only if you want your shaft to break. Drilling that hole probably weakened the shaft by 70%

Not A Good Idea.

[Sailmonkey]

Some stuffing boxes have a grease zerk on them. I would heasitate to use it on a pleasure craft, you're better off just letting a few drips per minute come through when the shaft is turning. The grease is widely used on commercial vessels, but the mess surrounding the shaft packing on larger vessels is pretty undesireable on a pleasure craft.

[Stevens 47]

Only if you want your shaft to break. Drilling that hole probably weakened the shaft by 70%

Not A Good Idea.

Not true through bolting is recommended practice as per Nigel Calder's book.

[S&S]

Originally Posted by Stevens 47

Not true through bolting is recommended practice as per Nigel Calder's book.

Then Nigel is wrong too. Loss of material strength is not author dependent.

[Chief Engineer]

My observations:

GFO packing does not require "dripping"
I have done everything from 18 foot catboats to 95 foot Tugboat stuffing boxes in the water.
Though bolting a sailboat shaft? Bad idea. One inch shaft minus 3/8 bolt= 5/16 of shaft on either side of hole. Big shaft.....I have seen that a lot....usually a drift pin

Some shaftlogs have a grease fitting on them because water does not come far enough up the shaft or the toreancle between shaft and stuffing box is close....

I see this on a number of foreign bottoms.

[cmesiam]

ALL,

I have found the issue. At the transmission, bolted with three bolts is a an iron 'collar' whhere the shaft slides into with a key. Then there are two (allen, hex) screws which were in bad shape. Also the key was brass and completely 'shaved' in half lenghtwise. To repair, appears simple: replace the key and set screws and reassemble. I think I could be steaming by the weekend. I'd like to tank all for their assistance. Coudnt have done it with out all of you.

Thanks again,

Bruce

[Fishspearit]

Some tips when putting it back together: As you found out, when you put it in reverse those set screws are the only thing holding the shaft in the coupling. It helps to take a sharp punch and dimple the shaft where set screws hit, so that they bite in a little deeper. Also, be sure to put loc-tite on the set screws since they like to vibrate out.