Hit a submerged object bad vidration now, what to do??

[peterkvs]

Was cruising home yesterday after going out for a nice cruise and lunch with my youngest daughter. A couple of miles from my slip and I run the engines up to full power. I like to see that I can achieve better than 2800 rpm and 28 kts and that all the operating parameters are normal. Was just up to 2850 rpm and there was a giant explosion which shook the boat, a shudder and maybe even rocked the boat to the starboard. It happened so fast. My first thought was that I had detonated an engine. I slowed to idle, which takes a while because I had the synchronizer on. I checked over the panel at idle and everything was normal. I came out of gear and opened the hatch and checked everything out. Everything looked normal. I could very easily spin the prop shafts by hand. Tried the gears in forward and reverse and all seemed normal. Put boat back into forward and look it up to 2200 rpm on plane. Made 20 kts, which is typical but noticed that the railing on the bow and the fenders baskets were shaking pretty hard. They did not shake before the event. I put each engine in drive separately and took them up to 2000 rpm with no real noticeable vibration on either drive, then took it back to 2200 and noticed the pretty bad vibration. I cruised back to the dock at 1200 rpm, pumped out and returned to the slip. While I was parking I noticed that when I engaged the port drive in either forward or reverse there was a slight singing noise. This does not occur with the port engine, and it stops as soon as I take it out of gear.

I am assuming that I hit some underwater debris, like a tree or log. I was in the center of a wide channel on the Tennessee River in about 50 ft of water. I have never hit anything before and was hope some with experience might chime in and let me know how to proceed?

I can call a diver to inspect and/or I can take it to a nearby marina where they can haul it out and inspect. I hate to haul it right now because I would have to winterize it as it has been freezing almost every night and some days. What is the likelihood that I did something worse than bending the prop? Could I have bent a rudder, strut, prop shaft? Would the shafts still easily turn by hand if I had bent something? How far to I let the inspection go? Just try props first? Seeing that it costs $400 to pull the boat I don't want to do that too many times.

Thanks in advance,

Pete

 

[skolbe]

Most likely at least the prop. I did the same thing 6 years ago. It was just the prop.

You would want someone to look at your shafts and rudders. I know it is warming up next week. Maybe wait a week or two and then have it pulled.

 

[HUMPH]

Sounds like a hard hit on the prop. There is potential of shaft damage but a good diver can verify that. 28 knots is more than I have ever seen in my boat.

 

[peterkvs]

Thanks Guys! Ken, when I first got my boat and it was totally empty of things, just me and 1/4 tanks it would go 30.5 kts! No idea on the RPMS because the tachs were crap.

Pete

 

[Sum Escape]

I winder if you should call your insurance and tell them you hit something, usually that kind of thing is covered. It's possible that they may pay for the haul out and winterization just in case you have more damage than you think.....

just a thought.

Good advice....don't surprise the insurance company later, put them on notice you may have a claim.

 

[mwph]

Pete- Is it Alred Marina that you plan to have the boat pulled/inspected at?

 

[peterkvs]

Yeah, I would be taking it to Alred.

 

[Boat Guy]

Hope you get it sorted Peter. Sounds like it could have been a lot worse.

 

[northern]

Did same thing in 2011. High vibration above 1200 PM. Called insurance started a claim. Got boat halled bent prop. Got both props retuned and had run out on shafts checked. Had strutts looked at and rudders checked for bent shaft. In all $1100, deductable on insurance was 950 so did not put im claim. We had hit a log and you could see the prop marks on the log. Last year hit a pile and put a 6" by 2' hole below the water line. Boat is double hull so did not get any water in it. Put in claim this time it was 10,000+. Best to have a real look with the boat out of the water.

 

[wetpaint]

Just my .02….I would see if you can get estimate and what is wrong before calling insurance company if you have a high deductible…..Sometimes it is not worth the exposure of an accident if it is close to the deductible…..Also, had ether check the transmission to make sure no damage was done

 

[Lake Erie Monster]

get it looked at you never know if a shaft through hull was compromised

 

[fwebster]

This is the post you didn't want to read……………

If you hit something hard enough to rock the boat and cause that much vibration, you very probably bent a shaft. Cats are very high torque engines and if you hit the prop directly, the engine did the damage. But maybe not; you might be lucky and hit the hull bottom, rocked the boat up and then just knocked a prop blade. Probably just need to count on having the props trued and a lanced again. Because there is a possibility of hull damage, strut damage, prop, shaft and rudder damage, you can't do anything without hauling the boat out. Once you do that, you need to visually check everything then pull the props and get a dial indicator on the prop end of the shaft as well as just inboard of the shaft seal inside the boat. I have the allowable tolerances at home and can get them for you in about a week………you guys have snow/ice forecast and I left for the beach. Strut damage isn't always easy to find and you might even have to uncouple the shaft and pull it back to clear the coupler to see if it will center the coupler when supported by the strut only.
THe ruder will be obvious and isn't involved in the drive line anyway.

Good luck with it ………………

 

[peterkvs]

Thanks Everyone for the advice. I think I will assess the problem before I contact insurance as my deductible is 1100.

Frank, running thought the event in my mind I think that what I recall as rocking the boat was the feeling that the boat went into a left turn. But as I think about the mechanics of what was going on I think the left turn was the result of me rapidly pulling back the throttles and really only pulling back the port engine and having the starboard engine lag because the synchronizer was engaged which caused the boat to yaw to the port. I've never hit anything with the prop before and was very surprised at the loudness of the bang. I literally thought I blew and engine or transmission and was surprised it was all still running when I got the boat slowed down. But time will tell. I think I will wait a couple of weeks until it warms up a bit so that I don't have to worry about anything freezing while the boat is out of the water. I would appreciate it if you can get me the tolerances. Do you have any advice on where to have the props overhauled? Is it worth taking them to someone that can scan the props? i.e. propscan?

Thanks again,

Pete

 

[peterkvs]

Frank,

One other thing, How can I assess the condition of the ZF gear?

Pete

 

[Boat Guy]

Pete, I used this company for prop scan. They are very good and held in high regard. In fact, Rusty knows him....

http://www.blackdogprops.com/

 

[Lake Erie Monster]

Years ago when i was a wee lad my father was pulling into a harbor in the family Steel Clipper (giant battleship of a thing) and one of the props slapped something and there was a very noticeable vibration (amplified by the steel hull). Dad killed the bad engine (dont ask me how he knew which one) and docked on one engine. the boat was later hulled and found to have a missing blade on one of the props. Shafts were ok and trans was fine also. granted not the torque of a cat but if the prop took the brunt of it then you may luck out.

 

[northern]

My policy has a 48 hour notification clause or I can not make a claim. I also write it up in the log book, date it and sign it with a witness if I have one. Never been asked to see the log book. To see the bottom if you have a water proof sports camera you can put it on video and tape it to a pole and hold it under the boat in any area you fell you might have done damage. Worked for me.

 

[Turtlesboat]

You're not going to see the full extent of the damage until you haul the boat. A diver will just see the obvious stuff. Not sure what a short haul costs down there, but it may be worth it to do a short haul, see what damage is done, take pics, drop it back in the water.

 

[fwebster]

Pete,

If you didn't stall out a motor, the chances of damaging the transmission is minimal. You really cannot evaluate it until everything else is running straight, true and vibration free. Since it is the least likely part of the driveline to have sustained damage, I would haul the boat, pull the props and have them trued then put a dial indicator on the shaft and see what you have……in that order….then go from there.

UNless a damaged strut is really bent out of line, you aren't going to see it until you get the shaft straight. If the shaft is within tolerances (I"ll try to get the allowable run out from the manuals for the 400/410 at the marina this morning) while it is coupled up and still in the strut, then you can eliminate the shaft. However if the shaft has runout, then it needs to come out and be put in a lathe at a machine shop and checked because the transmission and strut will effect the runout. At that point, you can determine if you want to try to straighten it or replace it ($1000 to have one made locally or $1850 for a new one from Sea Ray)

 

[ttmott]

I would add to Mr. Webster's that to fully indemdify the gears is to pull a baseline oil sample then pull another after you get it back in the water and run it for a bit. Look for excessive increase in chromium and ferrous above your baseline which are bearing and gear indicators.

Also make sure to look at the exhaust eductors - they have been known to break off also in hits.