Hit a huge log – what would you do?

Alex F

Well-Known Member
Nov 14, 2006
9,166
Miami / Ft Lauderdale
Boat Info
2005 420DB with AB 11 DLX Tender, Raymarine Electronics (2x12" MFDs) with Vesper AIS
Engines
Cummins 450Cs, 9KW Onan Generator, 40HP Yamaha for tender.
While cruising our famous Hudson river I hit a huge log (half the size of a telephone pole, it very will might be just that – telephone pole but not the full length). It must have been floating for very long time b/c it changed to the color of the water, so obviously I didn’t see it only until we hit it. When I looked back after the impact I got real nervous for a moment after seen the size of this thing. BTW, I’ve hit a log before but nothing this large. I have to mention that the log was floating perpendicularly to the boast during the impact. The bang was not loud at all, but from what it looked like we hit it in the middle, but I can’t be sure. I immediately started monitoring everything very closely. The boat didn’t loose the performance, nothing changed, bilge pumps didn’t go off (that was my biggest fear). I kept very close eye on everything to determine if we were damaged. The only thing I felt was a slight vibration. I continued on because I didn’t think there was an emergency to stop in the middle of the busiest water in NYC. When I got to our destination I began my dives under (with just mask and snorkel) to see where the impact was and if anything was damaged. I inspected all underwater gear and the hull, but I didn’t see any signs of the impact. Props looked fine as I inspected them number of times thinking that this would be the primary contributor to the vibration. I should mention that the vibration is present not constantly, sometimes I feel like it’s not there at all. So, not finding anything we continued with our trip home. We happen to be in 4-5 and occasional 6 footers in the ocean. The boat performed great and to my surprise it was able to stay on plane at 3100rpms doing 17mph. I had at that speed for some time until the sees calmed down a bit. The slight vibration was noticeable at times. It’s hard for me to make the conclusion, b/c I know that it’s a different ride when you in rough water. We had entered the inlet when it was getting dark, so I didn’t have chance to test it in the calm waters (I never go on plain in the dark).

I’ll be testing the boat in the bay trying to determine if the vibration is there in calm water. So far based on my observation in the rough waters the slight vibration is only occurs on plane, not getting on plan, not going 1200-1500rpms. BTW, I was at 1300rpms for another 2 hours getting to my marina from the inlet and felt no vibration.

So, my question is what would you do considering all the fact I had mentioned? Would you pull the boat out or would continue with the season? I have the dive equipment I can use to inspect it more thoroughly, but it’s very possible that if the props hit the log the bend could be so mild that I can’t see it with naked eye.

Any ideas would be appreciated.
 
IMHO - Probably nothing, but if the vibration was not there before I would go ahead and have it hauled and check. Don't want to make mater worse?? How fast were you going when you hit it? I hit a big log on the TN river once, but only going about 20mph no bigger, but like you dived to check it out and worried the rest of the trip. When I got back an pulled the boat on the trailer a week later everything looked good.
 
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Alex, It isn't likely that you would see the damage unless it ripped a rudder off or something major like that. If you're feeling a vibration what likely happened was you hit the log with one or more blades on your props and bent the prop. Given that it was a log you hit, not a rock, it may not have left any marks on the prop itself. You may also have bent a shaft or bent one of the struts that holds the shafts.

The only way to really identify what you bent is to have the boat hauled, have the props pulled and balanced, then have the shafts checked to make sure they aren't bent.

I wouldn't run too much with the vibration. Depending on what it is that's gotten damaged you could cause further damage by continuing to run it.
 
If you feel a vibration, particularly at your regular cruising speed, I'd haul the boat and get things looked at. A shaft could be bent or some part of the underwater gear could be knocked out of alignment. Ignoring it and running at speed could accelerate damage to other more costly parts of your propulsion system.

Sorry to hear about that- I've been there before.
 
Alex
I'm with the fellas on this one. If after you do some test runs locally and determine that the vibration is a new issue, I'd get the boat hauled and checked. It's funny but a chunk the size of a nickle taken out of a prop doesn't always produce vibration. But if something is bent, even slightly, it's more likely you'll feel it when running and it is darn near impossible to visualize underwater. Running at cruising speed with something out of whack could mess up your cutlass bearings or cause the shaft to abrade and possible fail in the future. Could damage your dripless too.

BTW, I'm very familiar with those barely floating obstacles up there. The Hudson and East Rivers were disaster areas in the 70s and early 80s. There was so much floating debris from all the deteriorating piers, and the wood gets so waterlogged that it is 7/8s below the surface. As a kid we always had multiple sets of eyes on the water ahead when we would go through those areas
 
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Alex,
My boat is still in the shop being repaired after my underwater collision but my damage was extensive. What I would suggest before hauling the boat out is have your marina do an alignment check. In my case the starboard shaft was .040 and the port .016 vs. a .003 spec. Both were bent beyond repair. If the shafts are still aligned then most likely its the props. If you or a diver could remove them without lifting the boat that might save you some money if the cost is less. From my other thread you saw mine were beyond repair but yours might just need adjustment and if you never had them scanned this could be an opportunity to have it done.

BTW my boat vibrated noticeably at 1500 rpm 10 miles back to the marina but no vibration at idle speed inspite of all the damage.
 
I am not sure what I would do, But having said that I suggest you call your insurance company now to go on record that you hit something. The concern would be if you go until the fall then haul out and something is damaged will insurance cover it after a 4-5 month lapse?

Dave
 
I am not sure what I would do, But having said that I suggest you call your insurance company now to go on record that you hit something. The concern would be if you go until the fall then haul out and something is damaged will insurance cover it after a 4-5 month lapse?

Dave

I would wait until you find out the extent of the damage vs. Your deductible. I would not have notified my insurance company if I only had bent props that could have been repaired. But since both my props and shafts were bent beyond repair, I went ahead and filed a claim which I am still waiting to find out how much they will cover. Also check your policy to see if your boat is new enough that they will replace parts rather than prorating the cost. My policy has a 7 year age limit before they would prorate costs.
 
.... I would hazard to guess the pole hit the hull and submerged below the running gear from the impact. (hopefully)....

This was my opinion as well, but I inspected the very bottom of the boat wile diving under and didn't see a single scratch. It's also possible that the log had lots of slime build up and it slid thru wtihout scratching or leaving any marks.

I'll be doing test runs today and will let you guys know what I discover.

I agree that this is a tough call, do all inspections now and have insurance claim or wait til the EOS and if anything is wrong pay myself.
 
If your props bit the wood, you would hear it. Sounds like a chain saw. That wood is hard and waterlogged. You should be able to see where the log hit the hull, well maybe not in our murky water, but it should be visible in the bottom paint. If you hit it dead square, then it may have pushed it under the gear. If you hit it off to the side, a shaft or strut may have hit it. Welcome to NYC, land of floating logs and floating bodies.

Next time call it into the CG and have them remove it so I don't hit it next week.
 
He went from no vibration to a small intermittant one. He dove the hull and so no visible damage. A prop that has one blade slightly bent will cause these symptoms. A glancing blow from the stump that the hull already contacted could very easily bend a single blade, and the deflection that causes the vibration may not even be visible without a dial indicator. If this were me, I wouldn't waste any time "testing", nor would I burn the $ on a haulout. I'd have a diver under the boat Monday to snatch off the props and I'd have them trued and balanced and back on the boat by the weekend.

The prop shop will tell you if the props were damaged and if that doesn't fix it, dealing with a slightly bent shaft can wait for winter.
 
As always the wisdom of Frank, comes shining through!:thumbsup:
 
I totally agree with Frank's guidance.. but I truthfully would also *consider* waiting until haul out in the fall, especially if I didn't plan any long trips for the rest of the season. Forget more testing - you won't learn more than what you already did that day. If there's no water in the ER by now, it didn't do any serious structural damage. And there is a chance the log missed all your underwater gear completely...

Re insurance, I probably wouldn't call them for this. I think you got lucky on this one Alex.
 
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Alex, Sorry to hear about your encounter with a log... I would guess that its the strut, shafts and prop... If you have not replaced your cutlass bearings, I just replaced mine and they were shot... I would pull the boat to check the cutlass bearings and and visibly check the shafts and props... I had my props done this year too, it made a dramatic difference in how the boat ran... Dillon's creek can change the cutlass bearing without pulling the shafts. If I were you I would pull the boat this week, after we raft up tomorrow...
 
He went from no vibration to a small intermittant one. He dove the hull and so no visible damage. A prop that has one blade slightly bent will cause these symptoms. A glancing blow from the stump that the hull already contacted could very easily bend a single blade, and the deflection that causes the vibration may not even be visible without a dial indicator. ...

Thanks Frank,

This is what prop guys said as well to be 95%. At this point I just pray it's a bent prop.

I totally agree with Frank's guidance.. but I truthfully would also *consider* waiting until haul out in the fall, especially if I didn't plan any long trips for the rest of the season. Forget more testing - you won't learn more than what you already did that day. If there's no water in the ER by now, it didn't do any serious structural damage. And there is a chance the log missed all your underwater gear completely....

Gerry,
More testing was necessary for me to understand if there’s a NEW vibration or not. I just completed the test in the calm water and sure enough found the answer. I took note of how she responded at different RPMs. I started feeling something different when getting her on plane. While on plane I was still not 100% sure, so I decided to shift the power and check each side separately. Having the boat on plane I pulled the throttle (keeping her in gear) back on one side while the other side carried the load. This method had clearly showed that PORT side indeed had some extra vibration while starboard side was smooth. So, now the answer is clear and I had scheduled the short haul out. At this point I just pray that it’s a prop on the port side, but just in case I’ll have both props tested.

....Welcome to NYC, land of floating logs and floating bodies....
Man that's some "nice" welcome I got from NYC. We had 2 days of 100degrees heat wave while we were touring the city with kids, then the fricking log. We had a great time on our cruise for the past week and were looking forward to visit again, but having this experience with the NYC waters I'm not sure the excitement is there for coming back.
 
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He went from no vibration to a small intermittant one. He dove the hull and so no visible damage. A prop that has one blade slightly bent will cause these symptoms. A glancing blow from the stump that the hull already contacted could very easily bend a single blade, and the deflection that causes the vibration may not even be visible without a dial indicator. If this were me, I wouldn't waste any time "testing", nor would I burn the $ on a haulout. I'd have a diver under the boat Monday to snatch off the props and I'd have them trued and balanced and back on the boat by the weekend.

The prop shop will tell you if the props were damaged and if that doesn't fix it, dealing with a slightly bent shaft can wait for winter.


I agree completely. Had the same experience with log and then immediate vibrations, had a diver go look and could not see even a mark on a blade. Gave me a good excuse to buy that extra set I wanted anyways. Changed them out and it runs normal, sent that set back for rework and ready if it happens again.
 

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