Someone have a bad weekend??

Anyone we know? What is the name and hailing port of the vessel?

Good week out on the boat, bad day traveling back. tranny is cracked in
half also. Everyone is ok and wants to get back out on the water.

Crete, sorry for your misfortune!!! I wish you a speedy repair

A log or submarine?? Ouch..
What clutch will you be looking for. Cry on us. Sometimes we can help (the forum).
We all have rose-budded a few wheels in our time. It can hurt (lott$)..

Crete, I feel your pain, but hopefully this will make you feel better: I met a couple while living in the Keys years ago, who while coming through an inlet into Islamorada in a 65' Viking on plane, missed the channel and struck a Corral head with his starboard prop/shaft. He hit it with so much force that it literally ripped out the back of the housing of his ZF tranny prior to tearing out the shaft and leaving it on the bottom of the canal. He admitted to having a few drinks (I'm thinking a whole lot of drinks). How he got into the yard without sinking is a bloody miracle! So, my friend you got off cheap. O.K. so maybe you don't feel better, but it could be worse!

So a Vulcan coupling didn't shear before as you say " tore the rear housing off his gear box?? There's a few sacrificial elements in the drive line before bits and pieces of ZF housing are thrown around.

Hi Capt. holli,
I still to this day think he was lying about how fast he was going...but they had the deck pulled up in the cockpit and there it was, plain as day the entire back half of the transmission casing was gone! And mind you it wasn't where the two vertical halves were bolted together...it was aft of the seam. I can make a couple of calls to find out the name of the yard that did his work down there...somebody must have some photo's of that disaster. I can't even imagine how incredible that must have sounded up on the flybridge!

Crete, Being from Westbrook, did you go to Pt. Judith by choice or due to the tow zone charge? We once broke down N/W of B.I. Tow to Pt. Judith or to within 4 miles of Montauk covered, but that last 4 miles was over $1,000. At least P.J. is only a ride up the road for you. For us it would have meant trains to NYC and again out east. To say we felt abused puts it mildly.

Were you in Nantucket? I was in slip 1225 last week. Sorry to hear about your trouble on the way home. I've been there too, fractured a shaft in Nantucket boat basin and dropped a prop some years ago. Diver got it and I ran on one engine to Hyannis, found the second shaft cracked too right at the taper.

Regards,

Ted
"OFF DUTY"

Sounds like someone didn't lap your props and tighten the prop nuts enough.

OFF-DUTY

Fluxed and lapped - what is that? Thanks

As far as I know, Magnafluxed is a way of checking for cracks and Machine lapping is finishing/balancing a shaft by rotating it between two rollers at varying speeds...

P46

Thanks. That seems like a heck of a lot of effort$ every year. You must have to remove the shafts to do it correctly??

If you have a membership to this site. Article mentions lapping the prop:

http://boatdiesel.com/Articles/Propeller-installation-Big-Nut-vs-Little-Nut/Introduction/Tony-Athens/A-35-1/Correct-Propeller-Installation.cfm

Fluxing and Lapping

Easier than it sounds. Fluxing a shaft entails painting a purple colored liquid onto the shaft behind the strut after you have removed the prop. Once the liquid dries, you spray it with an aerosol solvent that removes the dried flux. This leaves the purple color in any surface crack, easy to see with a magnifying lens. Typically the cracks start in the corners of the key way slot. A way to prevent this is to chamfer the corners rather than leave them square. When I lost the prop I spoke to several other owners including someone at Post and was told repeatedly that 50's have had shaft failures at the taper just under the prop. It may have something to do with the dimensions of the early 50's. I have 2 1/4 inch shafts and the prop is mounted about 2 1/2 inches behind the strut. This may cause a flailing action on the shaft weakening it over time. The metal lab that checked the prop said it was a long slow crack over time.

Newer 50's I believe ran larger diameter shafts due to more horsepower, but potentially to correct this issue. I have had my chamfered Aquamet 22 shafts for about 10 years now with no problem.

Lapping is just coating the shaft with an abrasive compound, then installing the prop without the key and turning it by hand for while so the taper of the shaft and the prop mate up better. Reduces the chances of any play in the shaft/prop connection that can lead to cracks by overstressing the key way.

Here is the lab report and pictures:

Presented for analysis was one 2 ¼” diameter marine shaft in two sections (Figure 1). The tapered portion of the shaft was fractured through the keyway region. The “beach mark” appearance of the fracture surface is indicative of high-cycle, low-stress fatigue (Figure 2). There are multiple crack origins both in front of and behind the key as indicated by the arrows seen in Figures 3 and 4. These multiple crack origins and cracking along parallel planes is also a characteristic of high-cycle fatigue. After initiation, the fatigue cracks slowly propagated through the shaft until the remaining cross section is no longer able to sustain the applied stress. The last portion of a fatigue failure is referred to as final or fast fracture. There was very little material left on the shaft before final or fast fracture, confirming that the stresses responsible for the cracking were relatively low.

Also noted was the lack of radius along most of the length of the keyway, as seen at the edge of the fracture surface in Figure 5. Radius was present at base of keyway. The sharp edges acted as a stress concentrators and crack initiation sites. In General approximately ninety percent of a shaft life is used to initiate a fatigue crack. The crack then propagates through the shaft for the remaining 10 % of shaft life. Conditions that help initiate cracks can therefore significantly reduce shaft life.

Chemical analysis was performed on the shaft using optical emission spectroscopy (OES). The results are attached to this report. The chemistry was consistent with Aquamet 22 type stainless steel. This is a higher strength grade with slightly lower ductility compared to Aquamet 18 or 19.

As a result of the above investigation and analysis, it is apparent that the failure was due to high-cycle, low-stress fatigue occurring over an extended period of time. As to the length of the key, the use of reduced keyways and keys is sometimes used to reduce stresses on the shaft. The fact that a slightly longer key could have fit in the keyway, is not the cause of this fracture. However, according to SAE Specification J755, fillets are mandatory for keyways in shafts above 2” in diameter. This specification requires a 3/32” keyway fillet radius on a 2 1/4” diameter shaft. The lack of this radius contributed significantly to crack initiation and ultimately shaft failure.

Yep, shafts have to be removed for it

You don't have to pull the shafts. Just lift and block the boat, do your prop repairs and then spin them on the shaft with compound.

Gentlemen, I am looking for a transmission ZF 1RM350PL.1 (1.58). ZF does not
make this one any more. They tell me the new replacement is ZF 360 (1.50), different
dimensions and ratio. The dealer claims it will work with the existing starboard trans.
Any ideas where to find one ?