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Lifting Boat While On Trailer
Posted: Fri May 23, 2008 10:19 pm
by Gazmn
I figure I'll brainstorm with you guys...
I have bottom paint on my X. And I need to repaint it and add a Keelguard.
I tried lifting the boat as high as the trailer jack would allow, placing blocking underneath the front end and then lowering the jack. I got about 4 inches of seperation. While this would have been enough to repaint, it's not nearly enough to strip the keep of it's paint to put on the keel guard. Any ideas to lift the front of the boat well off of the trailer - while in my flat driveway?

Posted: Sat May 24, 2008 2:34 am
by Kelly Hanson East
Gazm - you could put a 4x4 under the jack post (removing wheel and making up that difference with another 4x4 and then use that to get another 4 inches of lift. Block front end as before.
Posted: Sat May 24, 2008 3:25 am
by K9Kampers
How about just blocking the boat and remove the trailer altogether? Sure, it's a bit of work, but easily managable for one person. This would give you unobstructed access to the bottom of the boat without having to squeeze under / work around the trailer, never having enough clearance.
Posted: Sat May 24, 2008 5:51 pm
by Gazmn
Sadly, I can't remove my front wheel, Kelly.
& K9, I'd love to block it. But I don't know how I'd do this without a crane
If there's really an explainable way - do tell

Posted: Sat May 24, 2008 7:20 pm
by K9Kampers
I believe the process has been described here before, but it's a simple tho time consuming process, a couple of hours to half a day, depending on your energy level.
Use a rolling floor jack, solid blocks (wood or concrete), 2x & plywood shims.
Park the trailer tires on 2x pads. Crank down the tongue of the trailer as far as you can. Block the transom of the boat, raise the tongue enough to block it, then retract the jack & place a block under the jack foot/wheel. Jack up the tongue as high as possible. Block the bow of the boat. Lower the trailer to level.
By now, there should be enough clearance between the boat & trailer to move the trailer. It may be necessary to remove the 2x pads from under the tires to gain more clearance. Now the work begins...
The rest of the task is a process of moving the trailer forward to the bow blocking, then block again behind the trailer's cossmember/axle, then remove the forward blocking. Continue the process, moving the trailer ahead until it clears the boat. Add blocking to make four points of contact.
Reverse the process to put the trailer back under the boat.
In every step of the process, BE CAREFUL and think about what you are doing.
Posted: Sat May 24, 2008 9:23 pm
by Phillip
K9
Not sure how to put this...........I don't mean this as a crontradiction.
I used blocks with a beam across.
Kevin (on the board here) explained concrete blocks were quite unsafe as load bearing.
Of course I listened carefully.
Next boat arrived....out with the blocks and beam at the stern...lowered the boat down from the tilt tray truck and crack......one block just cracked open and collapsed....intsant...I mean in a fraction of a second.....and I had the big L shaped one too.
My wife was there, and got to screaming at me and John about how stupid we were, how "that man on that Mac Forum told you not to do that", and that from now on we always use a crane, and of course the stupid truck driver added fuel to the fire by agreeing with her and suggesting it should sit on tyres etc.
Now we hire a crane at $220 a time.
Wife won't let us stand near the hull during a lift, we have to have long guide ropes off front and rear.
I don't care how you approach it, but do be careful. If that thing slips on you while your under it....you'r not going to survive.
How do the boat yards install keel guard?
For the hassel involved would it be worth investigating.
Cheers
Phillip
Posted: Sun May 25, 2008 2:08 am
by K9Kampers
Phillip-
I agree that there is more than one way to accomplish the task. From my own exprience working in boatyards and blocking boats, 4 proper jackstands - for balance, and 2 solid wood blocking stations - for load bearing, would be ideal here. Although not designed for load bearing, jackstands alone could support this boat. However, to pull the trailer out from under the boat, blocking is still needed.
As I stated before - solid blocks (wood or concrete). Solid concrete blocks do not fail under load as the hollow ones can. All the blocking under my boat in the picture is solid concrete, with a tree stump at the bow. If I had more blocks, I would have set the bottom two courses of each station double + perpendicular cribbing. As it was, my arrangement here was solid enough to work on & under the boat.
I disagree with the idea of using tires to support a boat at the height required to remove a trailer from under. Sure, they have a bigger footprint, but stacked high under load have questionable, if any stability.
In all, this task must be performed SAFELY. If one is not able physically or is unsure of the mechanics of the process, then alternative means should be sought. Also consider going to a boatyard that allows owners to work on their own boats...they can lift the boat off the trailer with travellift, forklift, or crane, and set on their blocks & jackstands.
Posted: Sun May 25, 2008 5:04 am
by Phillip
Sorry....better explain about the truck tyres.
The boat is on the tilt tray truck, bow at the front of the truck.
No wheels or axels on the trailer...it acts as a cradle.
Attach truck winch line to trailer...stop it going anywhere.
The tilt-tray truck extends his tray all the way out (back).
Lowers stern on to 2 tyres on the ground, so bow is high in the air.
Then we spray water with soap on hull in front of bunks.
Driver then raises bow, and withdraws tray back to truck.
Boat slides off bunks.
Every so often, forces back edge of tray into ground, raises rear axels of truck off ground, and forces truck to roll forward.
Then when maybe only 6' of boat is still on the tray, raises it and we put 4 tyres (2 at 2 high) under hull (so bow is up...good drainage for cockpit) and truck pulls tray away.
We then brace hull to ground with an 8' 2x3 each side.
Then left with boat on ground, and trailer on tilt tray to be put elsewhere for work and assembly.
I have learnt a lot from your description, so thank you for that.
I bought 2 large steel beams 8"x6" (4.5m long) ($500) a while back.
Idea was to raise boat, have 4 stacks of pallets (higher than trailer guards) and run these beams on top of the pallets (front and back) and put boat on them.
Then we could push the trailer in and lower the boat on to it.
Wife won't let us tho.....and she always comes down to make sure we are doing things her way.
Don't stop me thinking tho.
Cheers
Phillip
Posted: Sun May 25, 2008 5:06 am
by Phillip
Sorry....missed something important.
We use the crane to put the boat back on the refurbished trailer.
Cheers
Phillip
Posted: Sun May 25, 2008 1:22 pm
by K9Kampers
Phillip-
I can see how the tires worked best for your application as described. And I wouldn't stack the tires anymore than two high if I did the same.
Pallets...know there's Yankee ingenuity for ya! I've certainly seen some creative (and scary) uses of pallets up here. What ever you have at your disposal. I've got conrete blocks.
As for the wife's way...ya gotta plan ahead...spring for a girls night out in the city, then while she's out you can do it your way without interuption!
Gazmn-
I hope these ideas give you something to work with. let us know how it goes.
Posted: Sun May 25, 2008 1:26 pm
by Gazmn
I'll look into the boatyard work and loading option. An application of single single season ablative is $350 -400 for them to do it. I figure add another $100 max for keel guard install.
When I'm not in the process of being overwhelmed I, like most of us, enjoy working on the boat. However, I can't seem to find larger than 6x6's for blocking.
Another interesting tidbit I came across. I mentioned the Keel Guard protection to a friend. He said he knows of someone who bought flatbed truck paint, you know the kind they use as bedliners; He put a thick and wide strip of this stuff on his keel for protection, then bottom painted it
For me it's too late as i've bought the guard already, and I really need the extra protection for driving the boat onto my trailer. Doing it with lines isn't really an option with how my launch is laid out.
Posted: Mon May 26, 2008 6:49 pm
by Chinook
A word of caution on using the trailer tongue jack in lifting the boat above the trailer. I've done this successfully a couple of times. Most recently, however, I managed to strip out a gear inside the jack. I finished the job using my spare tire screw jack, and had to install a clamp on pivot jack for the trailer. My conclusion from this experience is that a floor jack or similar heavy duty jack is a better tool for the job than the trailer jack, which normally only has to lift a small percentage of the boat's total weight on and off the hitch.
Posted: Mon May 26, 2008 9:03 pm
by Phillip
chinook
I have had a couple thru with the factory jack stripped.
I remove the top plate. Inside are 2 interlocking cogs: one in the vertical, one in the horrizontal.
The winding handle shaft goes thru the vertical and there is a cotter pin holding the cog in place.
To date, I have found by removing the bits of broken cotter pin from the shaft attached to the handle, and digging around in the grease for bits, I have been able to repair the jack to working condition by putting in a new cotter pin.
Got to get the bits of cotter pin out of the grease.....cogs don't like it too much when they go thru them.
Not saying this is the solution to yours, but just could be.
Cheers
Phillip
Posted: Tue May 27, 2008 4:24 pm
by Gazmn
Well, first part is done - Put the Keel guard on. Will bottom paint next.
Oh learned something the hard way. Re tandem axles: Take off the rear most set of wheels to increase leverage. But make sure your 2 tires can handle the load

Re: Lifting Boat While On Trailer
Posted: Fri Nov 21, 2008 12:10 pm
by The Mutt
If the rear of the boat is blocked could a 2 ton engine crane raise the bow while the trailer is removed? then lower the bow onto more blocking.
I'm looking at adding flat cushioned pads to truck stands for my blocks, they have height adjustment, are made of steel and I have them.
Glenn