1974 southwind vibration issue
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=36267
Printed Date: November-17-2024 at 3:25am
Topic: 1974 southwind vibration issue
Posted By: lx.crowell
Subject: 1974 southwind vibration issue
Date Posted: June-08-2015 at 1:22pm
| Have a 74 Correct Craft southwind with a 351. Last spring went through it all had a bent shaft, bent prop, and bent strut. Had the prop sent out and balanced and repair, replaced the shaft and coupler, and had the strut repaired back in spec. After all that the boat still has a hell of a vibration, like the windshield rattles and makes it annoying to ride in it for more than 20 mins. Any advice is appreciated. |
Replies:
Posted By: 74Wind
Date Posted: June-08-2015 at 1:41pm
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The wizards can comment on Shaft alignment and all that but in the meantime on the windshield, have you tightened everything that you can find? I rarely if ever close my windshield and as a result must periodically tighten the center struts a bit. Also there are a whooole lot of rails on a SW, go all the way around and tighten every last screw both at the deck and where the tubing goes thru the T's and also the ladder. You'd be amazed how much one loose joint in the stern rail can resonate to quite the racket ------------- 1974 Southwind 18 1975 Century Mark II |
Posted By: 8122pbrainard
Date Posted: June-08-2015 at 7:51pm
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Alexander, When they repaired the strut, was it straightened? Did they install a new cutlass? Was the shaft checked for straightness? Was the coupling matched to the shaft IE: interference fit on the bore? Are you sure the prop was repaired correctly? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: SNobsessed
Date Posted: June-08-2015 at 11:32pm
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Does it vibrate the whole time the engine is running, or only when in gear? If only in gear, is it at certain RPMs? Does it get worse with increasing speed? Any change when boat turns? If only in gear, the 1st thing I would do is try a known good prop. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: lx.crowell
Date Posted: June-09-2015 at 9:54am
| I had the strut straightened with a new cutlass bearing installed. The shaft is brand new from a guy out of Florida that used to be a supplier for correct craft, and he had matched the coupler to the shaft that he had sent me. When in neutral it does not vibrate the motor is real smooth, once in gear it starts to vibrate a little, it is worse in the midrange then gets a little better at top end. Not sure on rpm numbers cause my tach no longer works |
Posted By: SNobsessed
Date Posted: June-09-2015 at 10:36am
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I bet the shaft came from General Prop, that is where Boat Dr. (one of our gurus) sent me for mine. The shaft they provided is a little loose in the strut bearing, maybe three thousands ( this was with all new). I get vibration in reverse, but not fwd. Can you get any shake out of the shaft/cutlass area? If not, I would suspect the prop still. Maybe someone here can loan you an acme to try out. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: JoeinNY
Date Posted: June-09-2015 at 10:40am
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Who put the boat back together and did they do an alignment? If you turn the shaft by hand with the engine off does it turn easily and uniformly through the whole 360 degrees or are there areas that bind up? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: lx.crowell
Date Posted: June-11-2015 at 12:11pm
| I had put the boat back together myself, have a feeling it is an alignment issue cause the boat was dropped or ran aground by the previous owner. The strut had broken through the fiberglass on the bottom of the boat. I had it repaired by a local guy that does a lot of repair work for the local marinas. The prop I had sent out to a local that the marinas go to, he repaired and balanced the prop so I do not believe that it is the prop. Any suggestion on how to do an alignment on it? |
Posted By: 8122pbrainard
Date Posted: June-11-2015 at 8:43pm
It's in the "new" section and also found in the FAQ thread: http://www.correctcraftfan.com/forum/forum_posts.asp?TID=21279&title=shaft-strut-alignment-video" rel="nofollow - alignment 101 ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
lx.crowell wrote:Posted By: 8122pbrainard
Date Posted: June-11-2015 at 10:07pm
Alexander, How much do you know about the repair? How far back from the broken glass did he go with new glass? Was any reinforcement done like plywood in the immediate area of the strut? Can you see any delamination of the glass from old to new? If this repair wasn't done correctly, it may be a source of the vibration. BTW, the strut going through the bottom of the boat sure would have been useful information in your first post!!  Pictures? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: connorssons
Date Posted: June-12-2015 at 12:27am
| Pete! Excellent way to restart this issue he is having. Sometimes people don't think about the root cause! :-) |
Posted By: lx.crowell
Date Posted: June-12-2015 at 1:30pm
| Yea I had forgot about the strut coming through the bottom of the boat. The repair was done by a local body shop guy that does fiberglass boat work on the side. Very well known in our area and all the marinas refer people to him for repair work. All the broken glass was ground out and the repair area in total is about 2 square feet. He placed a aluminum support plate into the repair glass area directly above the strut mounting area, I believe the plate is about 1/4 inch thick. The new glass is not delaminated at all where it meets the old glass. I'll take some pictures of the repair area tomorrow, I think when I put the strut back on after the repair work it was not completely straight. |
Posted By: 8122pbrainard
Date Posted: June-12-2015 at 7:31pm
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Alexander, How is the aluminum plate attached to the hull or is it bedded in the glass? ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: lx.crowell
Date Posted: June-22-2015 at 8:29pm
The aluminum plate is bedded in the repaired glass. I was running the boat this weekend and it still had a bad vibration, had checked the shaft and it seemed to turn freely. All of a sudden the vibration had stopped i was kinda like this could be bad or good, well got it home and realized that the strut had broken in half. And as a result of the broken strut the prop gouged a pretty good hole in the bottom of the boat. So now the questin is does anybody know where i can find a 6a strut been looking and have found one for like $395. And what is the possibility that the shaft is bent?  
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Posted By: 8122pbrainard
Date Posted: June-22-2015 at 8:49pm
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Alexander, The 6A's are NLA. Get the 6A6 and if you want cut an inch off. I did for my Tique, http://s133.photobucket.com/user/brainard_bucket_bucket/media/DSCF0002-69.jpg.html" rel="nofollow">  Ground it down to taper the end and then when at it with the needle descaler to match the surface texture. I really question the integrity of the hull at the base of the strut. An aluminum plate bedded in glass will have bonding issues especially if he used polyester and not epoxy resin. I asked how far back into the old hull the repair was made. Can you tell from looking in the bilge and on the bottom of the hull? I have a feeling that strut wasn't soundly fastened to a sound hul and then vibrated to the point of failure. How many hours were on the boat after this "local guy" did the repair? Yes, I'd say the shaft is bent. Get it out and take the dial indicator to it. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: lx.crowell
Date Posted: June-24-2015 at 5:08pm
| I'll get a picture of the repair area and have a good look at it. I would say that the repair went about (this is an estimate from memory) 8-10in on all sides of the strut. It has about 10 hours of run time on the repair. Do you need to cut off the extra inch or can you just use the standard 6a-6? Now just throwing out a suggestion here, don't burn me at the stake, I am working on a 1954 Chris Craft plywood kit boat was wondering if it would be acceptable in the off topic section or somewhere for me to start a thread on the repairs? |