If it ain't broke don't fix it?

[ageless]

New to me 55c I am about to haul out to take some pitch out of props, 12v's need 200-250 RPM's. I do have a vibration I want to investigate as well. I don't have any documented service (past the last 6 years) on the cutless bearings and/or shafts so I was considering (reluctantly) pulling shafts and having them checked.

I have a dial indicator that would allow checking them while installed, is that sufficient enough to determine if shaft is true? I intend to inspect for cracks as well, although I would think those "might" have been documented during recent survey.

Confirm please: checking cutless bearings is a matter of checking play in the shafts and visually inspecting. What am I looking for to ensure the packing gland units don't need replaced? I intend to replace the packing here and in the rudders while its out

 

[Reefgeorge]

I don't know the Hatteras running gear set up but cutlass bearing play can be checked by grabbing the shaft out of the water and seeing if it clunks in the bearing for a gross check. Also, sometimes you can hear it when you go in and out of gear in the water. As far as checking the shaft runout without pullng the shafts, the most common thing is to check it at or just before the taper. The more play that you have in the cutlass bearings, the less useful this is. Also, you can watch the shaft rotation underway in the engine room as well as break the couplers and check the alignment with a feeler gauge.

A gross check on the props out of the water but still installed is to get a dial gauge or reference point firmly attached and rotate the prop checking the tip alignment as each blade goes by.

As to the title of your post, running gear work is the black magic of boat repair. Once shafts start coming out and props start getting pulled, let the gamed begin. Shafts and props can come back worse, you might catch a yard guy trying to bang a prop off with a sledge hammer, trashing your gear thrust bearing. IOW, yes - if it ain't broke don't try to fix it. Chasing small incremental improvements in running smoothness can be very frustrating and VERY expensive. Ask me how I know.

George

 

[mykim]

New to me 55c I am about to haul out to take some pitch out of props, 12v's need 200

I have a 55'C with 12v71's. I changed my pitch to 32"x30". Works great. As for the C bearing. Rule of thumb is, Grab the prop and see if you get any end play. There is some allowance for end play, can't recall the number,but there is a tad allowed. Wear heavy gloves. Those sucker can be lethal.

You may well find some prop work will do the trick. My boat has 650hp motors and with a fresh bottom and no water she'll do around 22-24knts. They aint fast. We never run her at those speeds, or very seldom. She mostly putts along at 10 knots. I open her up now and then to clear her throat though.

 

[luckydave215]

"If it ain't broke fix it till it is"

 

[Top Hatt Craig]

Although a actual measurement would be nice here's the gist of it .. https://m.youtube.com/watch?v=6iy8gQR3DoA.

 

[ageless]

Understood!! I am personally going to pull the props and have them pitched and balanced and we'll save all the other goodies for winter

 

[t109a60]

On the shaft straightness question, I have had success checking for run-out with the shafts in place
using a dial indicator. Check midway between cutlass bearing supports and between the rearmost
bearing support and the strut. If one shaft is noticeably worse, that's your likely source of vibration.
I did this, pulled the offending shaft and had it straightened by a reputable prop shop. Much improved.
Of course, this only works if the cutlass bearings are still tight.

As further confirmation, my 'bent' shaft (0.015") was noticeably harder to turn by hand.

hope this helps.........

 

[racclarkson@gmail.com]

With vibration and nothing obvious on shafts or bearings on my 55C, I was happy with the result after the props were done.

I'm running 30 X 28 with 28 X 28 spares.

 

[ageless]

With vibration and nothing obvious on shafts or bearings on my 55C, I was happy with the result after the props were done.

I'm running 30 X 28 with 28 X 28 spares.

Interesting....mine has 27 x 29 but they're being worked to get 200 RPM's out of them
Have 30 x 28 spares

 

[Reefgeorge]

A word on maximum turns and pitch. Make sure that your turns are pitch limited and not throttle position or governor limited. I don't know the engines that most of you guys have in your Hatts but another common check are various temperatures to indicate load at max throttle as a cross check, or at least it is in my MAN world.

George