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View Full Version : Any boat lift experts. Boat lift failed this weekend



MC
09-08-2009, 10:33 AM
Need so thought about why this happened.

Well, not the greatest weekend for boating. The bunk brackets on my boat lift failed, causing the boat to fall on the lift. Some minor damage, but could have been much, much worse.

Long story short, the brackets failed after putting new 2x12 bunks (needed the larger bunks for some clearance issues for the boat lift cables).

On Friday the boat lift guys had relocated the old bunks using 4x4 inch aluminum brackets (the old brackets were 8x4) .

On Sunday, I was able to inspect the lift in the water. When I inspected the lift, it was way out of square, bunks were pinching agaist the thru hull and raw water pick ups. All the brackets were crooked and could not get the boat to sit on the lift. Kept the boat off the lift due to concerns.

Decided to try and fix the mess by installing new bunks on Monday and making sure everything was square and so the bunks would sit outside all the thru hull fittings/transducers etc.

After putting the boat on the lift for about 5 minutes, the boat fell (we were actually lowering the boat to take the boat back off the lift at the time. I wanted to leave the boat off the lift for an inspection by the boat lift company on Tuesday.

Photos are of the failed boat brackets, and how they are installed. Photo 1 is how they left the lift bunks ( I have a bunch of these photos showing other problems. Photos 2 and 3- the bracket failures. 4 and 5- how the brackets are installed on the bunks (2 of the brackets did not fail outright, but are bent).

Boat is about 8k lbs. Boat lift company new this when they did the installation of the brackets (represented in photo 1).

My question is- would these 4in brackets failed regardless of what size bunks I was using old bunks were 2x8, replaced with 2x12). If I used the wrong lumber, should they have failed so quickly?

Islander
09-08-2009, 10:49 AM
I'm no experet on boat lifts. But there's several things that trouble me with that installation:

1. The way the aluminum brackets sit on the steel beams is quirky - not a lot of contact area between the bracket's bottom flange and the beams's top flange. Also the way in which the bracket is attached, with those compression bolts off the bottom flange, allow the brackets to move, whihc they did; they should have been thru-bolted to the steel top flange with a large surface area of contact
2. Aluminum is weak and the evidence is in the way those brackets sheared off, brackets should have been stainless of galv. steel
3. What is causing the bunks to move horizontally - that was the cause of the failure, made worse by a tall bunk which then multiplied the sideways force to the bracket, until they sheared off. Those brackets were not designed to handle sideways forces
4. Bunks that tall should be thicker (3x or two 2x's), but not the cause of the failure and they appear solid - they just weren't properly anchored to the steel beams

MC
09-09-2009, 10:10 AM
Here is what I think happened.

After they installed the new brackets and set up the bunks initially, the boat was lifted and the bunks got twisted between the transducer (this is one of those B260 huge thru hulls) and the large raw water pickup (see photos). The brackets started to bend/fail at that point. My boat is 8Klbs (maybe a little more) the brackets are 4inchx4inch aluminum. It's a 10k lift.

I took everything apart to square it up and reset the bunks so they were outside all the hardware underneath the boat (thru hulls, raw water pick up, transducers). I tend to think the the damage was already done to the aluminum brackets. The boat sat on the lift for almost 48 hrs before being taken off the lift for the first time, all twisted. When I put the boat back on the boat lift after squaring everything up, blam- 2 of the brackets fail. The alumumin brackets were bent one way then bent back the other way (square).

From what I understand about aluminum, it is a very brittle metal and torque is not a good thing. Using 2x12 rather than 2x8 probably did not help, but the wood did not break or fail, the brackets did. Someone would have to explain to me why using 2x12 is a bad thing.

Some positive things, the boat is back in the water. Appears to be no damage, other than a fuel vent fitting that popped off when the boat layed against the piling. I was going to replace it with a stainless steel on anyway.

Kurt
09-09-2009, 10:30 AM
MC...

Check around the xducer fairing block. There seems to be a little cracking or some sort of separation/movement in the bedding on the side where it sat on the bunk. May just be normal or the way the picture was shot but I'd check it.

Also, when you went from the 8" to 12" lumber, you increased the lever arm, and torque, by 50% on those brackets (which look a little thin to me anyway). So, an original torque force of say 1000# would have become 1500# - possibly the straw that broke the camel's back.

I have to agree though, the initial mis-alignment and forces put on them by being pushed around by the hull protrusions might have been contributory to their failure.

quickstep192
09-09-2009, 11:01 AM
On most of the lifts I've seen, the bunks are resting right on the cross beam, not resting on a bracket like the lift in the attached picture. I agree that the brackets seem undersized, especially when made of aluminum. If not form weight, seawater and galvanic corrosion will ultimately kill that connection. Initialy I wondered why the brackets were set up like they were, then I noticed the tunnel they create for the cable. Mine's not set up that way, the cable "rides" in the web of the I beam. I can take pictures if you'd like

MC
09-09-2009, 11:08 AM
When the boat is back out of the water, I'll give everything a good look over and make sure none of the fittings are damages.

I tend to feel that because of the mis-alignment, those brackets were a failure waiting to happen. When a boat sits on a lift, it will sway at some point in time- either via wind or when getting on the boat, or even a wake from another boat- something will make it sway, they do not sit there like stuck in concrete. With the boat being wedged, the aluminum brackets are already being bent- bending alumium is BAD aluminum breaks, not bends. Now start swaying 8klbs and you got a problem waiting to happen.

I also had reservations about the brackets and their size, but was told, and still being told "that is what we use". The boat lift company tried to argue that the prior brackets that were used were also 4" x 4", but in fact were 4"h x8"wide (although not that thick. May only be 1/4 inch aluminum). I have photos to show that as well. "Special brackets" for this 3-piling lift are being made this time. I have no idea why "special brackets" where not originally made. It's the same lift they installed 6+yrs ago and have serviced several times.

Thanks for the insight on the 8" and 12" increase. Certainly would have put more pressure on a damaged bracket.

Quickstep-
Not sure why the cable needs the tunnel like you noted and does not "ride" in the web of the i-beam, but that's how it works. That tunnel has never been an issue. Not sure I want them to even address that issue. The lift itself has been great for over 6 yrs.

Islander
09-10-2009, 09:53 AM
The last photo you posted tells the story - the hull is pushing the tops of the bunks outward, and the brackets were too small and weak to hold that rotation force, made worse by a tall bunk.

That system of weak brackets and tension wires is an accident waiting to happen. Maybe they are suitable for lighter boats, but for a heavy hull, I wouldn't support the bunks on anything less than galvanized steel angles, 5" high by 3/8" thick, throughbolted and continuous between the main steel beams - in other words the steel angles span the main beams. The bunks can be tall, but they should be 3" wide and angled for better hull support surface contact area. That's just the way I would do it and never have to worry about it again.

Islander
09-10-2009, 08:51 PM
Just got the latest issue of Florida Sportfishing (September/October) and they have a feature article on boat lifts. Good article with photos of very strong bunk brackets, etc.
If you can get this issue it should help you with your lift problems, it's also a great fishing magazine:

http://www.zinio.com/browse/publications/?productId=500252370&offer=500101011&bd=1

MC
09-11-2009, 09:19 AM
Well I've had some other boat lift service guys come take a look at my lift as well as made some calls inquiring about getting brackets for the bunks (and asking what size to get).

Without explaining what happened, and getting a quote and explanation of what they woudl be doing to get my boat on my lift, I gave them some insight to what happened over the past week. I showed them the brackets that the other company was using. Without wanting to "bash" a competator, there was enough discussed that it was clear that the brackets were way to small for the job they were supossed to do. That, with the terrible set up by the lift in the mean time, no surprise there was a problem. Other issues (like reusing bent hardware, resuing wood bunks that are over 6 yrs old and have many redrilled holes, using guide posts improperly, etc ect) clearly show a half-ass job.

Not one was concerned about me using 2x12. Everything would have been fine if it was not for cheaply fabricated, undersized brackets. And putting the bunks right in the middle, and up against all the stuff under the boat would also create a problem.

appears No damage to the boat-other than a minor scratch, just frustration by the boat owner (ME).

Tried to be "loyal" to the boat lift installer, but clearly their service guys are poor poor poor. Found another service company that will take the time to do it right.

The lift itself is GREAT.

mike s
09-11-2009, 11:38 AM
Just got the latest issue of Florida Sportfishing (September/October) and they have a feature article on boat lifts. Good article with photos of very strong bunk brackets, etc.
If you can get this issue it should help you with your lift problems, it's also a great fishing magazine:

http://www.zinio.com/browse/publications/?productId=500252370&offer=500101011&bd=1

Islander, I know this is off topic, & sorry for that, but will you be so kind as to explain how one may attach a link such as you have done here? Maybe a new thread? Thanx...

Mike... '81 PENN YAN

mike s
09-11-2009, 11:41 AM
Well I've had some other boat lift service guys come take a look at my lift as well as made some calls inquiring about getting brackets for the bunks (and asking what size to get).

Without explaining what happened, and getting a quote and explanation of what they woudl be doing to get my boat on my lift, I gave them some insight to what happened over the past week. I showed them the brackets that the other company was using. Without wanting to "bash" a competator, there was enough discussed that it was clear that the brackets were way to small for the job they were supossed to do. That, with the terrible set up by the lift in the mean time, no surprise there was a problem. Other issues (like reusing bent hardware, resuing wood bunks that are over 6 yrs old and have many redrilled holes, using guide posts improperly, etc ect) clearly show a half-ass job.

Not one was concerned about me using 2x12. Everything would have been fine if it was not for cheaply fabricated, undersized brackets. And putting the bunks right in the middle, and up against all the stuff under the boat would also create a problem.

appears No damage to the boat-other than a minor scratch, just frustration by the boat owner (ME).

Tried to be "loyal" to the boat lift installer, but clearly their service guys are poor poor poor. Found another service company that will take the time to do it right.

The lift itself is GREAT.

Luckily no real damage & most important; NO INJURIES! Good luck with the fix...

Islander
09-11-2009, 11:59 AM
Islander, I know this is off topic, & sorry for that, but will you be so kind as to explain how one may attach a link such as you have done here? Maybe a new thread? Thanx...

Mike... '81 PENN YAN

My pleasure. Just open any webpage of interest on your browser, preferably under a new tab, and highlight the web address at the top of the browser (place your mouse over the adress, left click, and the address will be highlighted in dark blue or other color), then while it is still highlighted keep the cursor over it and right click, then select "copy" in the dialog box that pops up. Then you can insert it into your post (or any other windows document)by right clicking where your cursor is located, and select "paste", that should do it.

tolomar
09-11-2009, 12:15 PM
Anyone have information about Shamrock Bankruptcy. Are they not making Shamrock Boats anymore?

MC
09-25-2009, 09:08 AM
Well finally got my boat properly on the lift. I ended up doing it myself (with the help of a brother in law).

The boatlift manufactuer sent me the correct brackets and all new hardware last week, so I knew I was using the correct stuff. Got tired of waiting for another service company to show up, so spent a few hours getting everything set up. This is not rocket science, probably 1 beer more difficult then setting up a boat trailer.

I completely removed all the stuff and brackets the boatlift service company did and started from square one.

My boatlift is a 3 piling boatlift (like a triangle) and the boat fits with about 6 inches of clearance (3 inches on each side). Thus there is not a lot of "goof room" available. So basically, you need to be sure: A) locate the exact center of the boat lift via a measurment of one of the pilings. B) make sure take your measurements for the bunk placements of that center line. C) Using some basic geometry make sure you put the bunks so they do not hit any of the fittings under the boat. D) make sure the bunks are square.

I guess it was too much to ask to have service people who could actually read a tape measure.

Still going to have a different boat lift service company go over the lift, and get familar with for future service. Figured it would be a good time to have them look at it while it's functioning properly.

I'm not going to post too much about the boatlift installation company on a public web site, but issues included:
-boat falling off lift
-shorting out the power to the house (and not telling anyone)
- rude comments to wife
-entering my house and stealing money (from my son's room) and taking some other small items.