Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Supporting a vessel with concrete blocks while working

Posted by JohnnyCW on 09/15/09 - 8:27 AM
#1

I have gotten tremendous pleasure from following various projects posted here and I am thankful for the generous time owners spend taking pictures of their progress. However it scares the hell of of me each time I see the weight of a vessel supported on concrete blocks. In my professional career, I have recovered too many corpses from under loads that were supported by failed concrete blocks. Concrete block can be very strong when used in the manner they are designed, but supporting the weight of vehicle and vessels isn't a use they're intended for. At the very least, orient the blocks correctly so the cells and webbing are vertical in which their compressive strength is greatest. Also, alway use something like hardwood lumber between the load and blocks to help distribute the load evenly across the block. Please take into consideration the possible consequences if a block were to fail while working under the load. They fail instantly and without warning.

Posted by Tom W Clark on 09/15/09 - 8:46 AM
#2

I absolutely agree with that. Not only can CMU crumble unexpectedly, but it is not hull-friendly; if it comes in contact with the gel coat, it WILL scratch it.

Solid chunks or wood are both strong and resilient and won't scratch the hull. Large blocks of styrofoam are also commonly used and will conform the shape of the hull to some degree.

Posted by MW on 09/15/09 - 9:04 AM
#3

Yea, they break ! I always put something under there "EXTRA" when working, like a spare tires on a rim, extra jacks and jack stands. You can't make a mistake by making it "too strong". I try and do as much as I can "ON" the trailer, that way nothing can fall on you.

Posted by Binkie on 09/15/09 - 9:45 AM
#4

That's great advice. Recently, while working on one of my rental homes, I drove by this house everyday, where someone was working on his car. From what I could see he pulled the engine out and replaced it with another one. He was working on this car for a couple of weeks. The car was jacked up and and a concrete block was put under each rocker panel, in the vicinity of the dash, so there was a lot of weight cantilevered in front of the blocks. To top it off the blocks were laid with the webs horizontal instead of vertical, and no wood block was used. The edge of the rocker panel directly on the block. I was tempted to stop a couple of times, but didn`t, as in my experience strangers don`t want advice from other strangers. Well, he got away with it, this time, in two weeks the car was up and running.. People do stupid things. When I was a kid a neighbor suspended the front of his car from a single rope tied to something on the garage ceiling frm the bumper. The wheels were off the car. Well, the rope broke, and he was crushed like a bug.. End of neighbor. .

Posted by whalerman on 09/15/09 - 2:04 PM
#5

WELL PUT!!! You can't enjoy the Whaler if you are 6' under and pushing daisys either!!

Posted by LabCab on 09/15/09 - 2:38 PM
#6

You are right. On my personal page it looks like the blocks are not oriented correctly but it's moisture on the one block that makes it look that way. Boat was on the blocks for about 10 minutes while we got it off the trailer.

Posted by Bake on 09/15/09 - 5:49 PM
#7

I agree with this post. If most people knew how easy a block wall was to push over they would be scared to death. Again the blocks are built to withstand a load in a vertical direction. The thing about supporting objects with the blocks is if the first one pops there is no way that load stops before it hits the ground.

Posted by CES on 09/15/09 - 6:45 PM
#8

Binkie wrote:
The car was jacked up and and a concrete block was put under each rocker panel, in the vicinity of the dash, so there was a lot of weight cantilevered in front of the blocks. To top it off the blocks were laid with the webs horizontal instead of vertical, and no wood block was used. The edge of the rocker panel directly on the block.


Growing up in South Florida, I saw this a lot as a kid. Never a good practice unless you take the proper precautions using the cinder blocks as described in these posts.

Posted by sraab928 on 09/16/09 - 3:18 AM
#9

Last year at a local boat yard a long time yard man was killed by just this. He had been painting boat bottoms for 30 years at this place. He lost his life to failing concrete blocks.

I bought boat stands about two years ago and this year I bought mobile boat cradles for working in the garage.

http://img.photobucket.com/albums/v47...4_1468.jpg

Edited by sraab928 on 09/16/09 - 3:19 AM

Posted by Derwd24 on 09/16/09 - 7:10 AM
#10

Those mobile cradles look very useful Scott in terms of boat mobility in a small space. What does a pair go for?

Posted by sraab928 on 09/16/09 - 7:30 AM
#11

Well I placed an ad in local boat sites and craigslist. I figured with dealers going out or downsizing I might get a deal - I picked up 4 for $150.00 total. Two were really nice adjustable ones. The other two are fixed height bunk models but still very functional.

Posted by JohnnyCW on 09/17/09 - 5:45 AM
#12

Williams Engineering is one manufacturer of such boat dollies. Maybe a little expensive new for the home enthusiast but they have other stands and poly blocks with a more appealing price.

Posted by Binkie on 09/17/09 - 5:51 AM
#13

I see many boats blocked up at boatyards using big blocks of foam. I guess its a good practice, apparently the foam doesn`t split , and I wonder where you can get foam blocks.