Bottom painting support

LarryE-old · Post by **LarryE-old** » Thu Nov 23, 2006 9:59 am

It's that time of the year again.
Want to try something different this year, painting the whole bottom, on the trailer.
Have two long bunks, one on eash side to support the boat. I have cut them in half so now there are 4 bunks.
Have acquired 2 boat yard jack stands. Want to jack the boat up with a 6 ton hydrolic jack, right behind the daggerboard. By placing the jackstand under the boat I can drop 1 set of bunks, at a time and paint under them.
I am making a piece, from Al. channel, to place under the jack, to spread out the load.
Any advise?

Post by **Tim Bosma** » Thu Nov 23, 2006 1:12 pm

Larry,
Spread the load on the hull at the jack. You don't want to punch a hole.

Jim Kloss · Post by **Jim Kloss** » Thu Nov 23, 2006 1:15 pm

I've successfully used a similar technique several times -- until this year. My trailer came with four bunks, and I just placed a jack on the crossbar and 2" lumber under the boat to spread the load. Up a couple of inches, remove the bunks, sand and paint.

This year, however, the trailer showed the effects of 25 years of corrosion and the cross bars started to crack at the center. I backed off, of course, and tried jacking from concrete blocks just fore or aft of the cross bars. That didn't work so well; the boat and trailer shifted together rather than the boat lifting off the trailer.

I expect that has to do with the geometry of the lift points, axles and weight distribution of the boat. Your plan might work or you might encounter a problem similar to mine.

Jim Kloss
s/v Ambivalence
S2 7.9 #8

LarryE-old · Post by **LarryE-old** » Thu Nov 23, 2006 1:24 pm

My post was unclear. I will use a 3 ft. pcs. of Al. channel, between the jack and the hull, to spread the load.

Post by **Tim Bosma** » Thu Nov 23, 2006 8:10 pm

Larry,
Good, I didn't catch that with Al. channel. You do want to seperate the boat and trailer so using the crossbar of the trailer as a base is good. I would recommend building up a stack of wood under the bar to take the pressure.

Jim,
Maybe you could box in the crossbar by having 2 stacks - one on each side, then have a 2x6 plank on top of the stacks just over the bar. The pressure would be on the stacks, but the plank would hold down the trailer.

BarryE · Post by **BarryE** » Fri Nov 24, 2006 10:14 am

I seem to remember a post from a few years back on this same issue; but my trailer has 8 bunks, four in back, and four up front, we blocked the trailer up so it wouldn't shift, then used three jack stands; two in back, just behind the bunks but directly below the winches where the aft bulkhead is, the third jackstand went under the trailer, in the center just ahead of the centerboard, working slowly we lifted the boat clear of the trailer.
With a couple more jack stands you can actually work the trailer out from under the boat, jacking and moving the center stands a few feet or so at a time.
Rule for any method, go slow, be careful.

Stef · Post by **Stef** » Fri Nov 24, 2006 7:12 pm

I went through this just this past spring. I have 4 bunks all running parallel to each other. I dropped the inner bunks without jacking up anything, did as much work as I could except final VC17M from this point. When all was done I pushed the bunks back up and then dropped the outer bunks. Did everything including VC17m then pushed them back up and dropped the outers one more time for final VC17m. After I was all done I pulled the trailer to a level paved area and adjusted all the bunks and posts.
This worked out for me, it was hassle free too.

Norwalk-ROTC · Post by **Norwalk-ROTC** » Tue Mar 13, 2007 1:26 pm

Maybe I am missing something, but it sounds to me like you could use the hydraulic jack to lift the trailer 6" or so, block it there and then place the two yard stands (normally adjustable) under the hull in an area not covered by the bunks. Then you could lover the trailer a few inches and remove the bunks while sanding and painting. The area you couldn't do with the stands under the hull would have to be done once back on the bunks, but that would be the case which ever way you go about it.

I wish we had a trailer.

tpf · Post by **tpf** » Tue Mar 13, 2007 3:28 pm

Before trying to raise the boat off the trailer make sure the trailer is stable. I did it a couple of years ago by using jack stands under the trailer to make sure the trailer did not move with the boat partially lifted.

I put the jack with a wood block directly in front of the keel where the hull is thick and the centerboard trunk reinforces the hull. I believe there is a steel frame around the opening also so it is pretty sturdy. I jacked the front up first then the back.

Shortly after that my trailer was stolen so my boat is 4' off the ground on jack stands so the process is a lot easier now.

I don't miss the trailer at all.

LarryE-old · Post by **LarryE-old** » Tue Mar 13, 2007 6:14 pm

Job is complete and the boat is back in the water.
Learned a lot. I was able to jack the front and get the bunks out pretty easy.
The back two bunks were a different story. Finally had to jack the boat off the trailerwith the jack between the trailer and the boat.
All the trial and error is complete and next year will be much easier.

BarryE · Post by **BarryE** » Tue Mar 13, 2007 7:04 pm

Good deal,
Spring Break; two weeks from now, I'll be doing the same thing.

S2 7.9 Meter Class Association