Give Me Your Thoughts

[88Ski]

I have a 88ski, two weekends ago in northeastern Ohio we had a 60 degree day and a buddy and I thouht it was to nice of a day to not be on the water. There was only one downfall, the lake was drained to the winter pool level. Well I'm sure you know the rest of the story. While making a 40MPH footing run we hit something and that was all she wrote. The boat had a bad vibration when going higher than idle speed. Jacked up prop, thats what I thought. I pulled the boat out of the water and the prop looked fine, if you really looked at the prop you could see one blade very slightly had more of a cup on the tip of the blade than the others. But I'm telling you this prop looks perfect. There was alittle gel coat damage to the right side of the strut about .750 dia. My question to this group is what do you think is wrong? Drive shaft bent? Strut bend? Transmission out of alignment? I'm Just confused by the prop not looking like a it was ran though a garbage disposal.

[AbunDiga909]

I don't know much about mechanics...esp. when it comes to marine. However, our '82 Ski Nautique has gone through countless props and we know, that even the slightest chip can cause vibration throughout the boat. And I figure if a chip and do it, a little dent or whatever you have may do the job. Also, whenever we put a new prop on the boat, it rides beautifully compared to what it had on the slightly damaged prob. My dad once went over a little piece of wood...and that did the boat a ton of vibration for the rest of the season. There were many problems that year however, but the wood may not be the cause of that. Hope this helps!

[skinautique]

It is possible that the strut is bent, the shaft and the engine out of alignment. Since you say that there is gelcoat damage near the strut, that would be my first culprit. The next would be the shaft. Does the prop spin somewhat easily if you grab it with your hand and try to rotate it? If not, chances are the shaft is shot too. I would definately check the alignment on the boat. As far as the prop, I have had brand new reconditioned props that vibrated so it doesn't take much to make them out of line. Hope this helps. Good luck and let us know how it goes.

[NautiqueJeff]

I agree that slight damage to the prop could cause that vibration, but I would also be suspect of the shaft/engine alignment. I'll post the procedure for checking that in a minute.

Ok... Here you go.

[seven20]

a friend of my dad's resotores wooden antiques in north ga, and works on inboards. he had one come in with a vibration that the prop looked perfect, even when measured but they changed it anyway and it cured the boat (of course, this was a mastercrap :twisted: ) If it seems to have slightly more cup than the other blades, you may check it out anyway

[tryan]

borrow a prop and check it. i have a indepth alignment procedure for slightly bent shafts if you want me to email it to you.

my '72 was so far out of alignment when i bought it that the shaft did not even hit the hole in the hull, much less be within .003.

nibral props are pretty stout animals. it sounds like what ever you hit was on the starboard outside edge of the prop and was smacked away. it's not a pretty sight when a log goes inbetween the prop and the hull.

[SGY]

Not a pretty site

I agree that submerged logs and boats do not mix. In March of this year, my buddy and I took out his brand new 01 SN 196 for break in. (He bought it new from a dealer in Nebraska that had the O1 left over.) The boat had less than two hours on it when we put it in the lake. After several hours of breaking in the boat, we couldn't resist but to ski. Well, on our last run, we ran over a submerged log/tree. Tore off the rudder--clean--and pushed the strut up through the bottom of the boat. When I popped the clamshell I could see flotation foam floating in the bilge with water coming in. It still makes me sick just thinking about it. Two guys in a Malibu Sportster (anyone in an inboard is cool in my book) pulled us to safety. Otherwise, we would have sinked and swam in.

The story has a happy ending. Thank goodness for insurance companies. They paid to fix it and it runs and skis llike new. Before that I was about the slit my wrists since I talked him into taking the boat out that day. If we would have waited a week, the warning bouys would have been in place and we would have been safe.

Not sure if there is a moral to this story--except my boat goes nowhere that I'm unsure about.

[88Ski]

Thanks for the input guys. I think the first thing to I'm going to do is pop a prop on and see what happens in the April. I'm just trying to get a head start on checking everything that I can to check if the drive shaft for strut are bent. Does anybody have a suggestion for these tasks? The only thing I could think of is to put a dial indictor on various spots on the drive shaft and spin the drive shaft to see what the run out is. As for the strut I can't think of any way to do it on the boat.

[R-mallis]

the same thing happened to our 90 sport, we hit something when were just idling through the water, we never found out what it was but it was enough to stall the engine. anyways, as you did we had to idle all the way home because of the vibration. It turns out after we pulled it out of the water i started it up and put it in gear and you could see the whole shaft was bent. anyways what im getting at is that if i hit something idling and bent a shaft and you were doin 40mph chances are you probably have a bent shaft. sorry for the bad news but i hope this helps you figure out your problem. by the way our prop looked about perfect also