How to flip an upside down 15 foot boat?

[darkbloom]

Just bought a lovely 15 foot tri-hull. I love it. Only problem, it's upside down on a trailer. Bloody thing weighs a ton, three men cannot simply pick it up and turn it over. Trying to figure out a system with ropes and pulleys... There must be a standard way to flip boats? Any suggestions are highly welcome.

[SeaSpark]

A common way to flip a hull is putting it in a circular rig with the centre of gavity of the hull in the middle of the circle. The boat can easily be rolled over.

Building such a rig for a one time occasion is a lot of work, this is a tri hull so i suspect the circle will have to be large in diameter to accomodate the hull.

You can also try to hoist the boat from about the middle of the center bow and stern (where the centre of gravity is), this will also make it easy to rotate or flip.

Perhaps you can lift it from its trailer under a bridge or viaduct this will provide a good strong point to attach your hoist cables. Don't try this on a buzzy road, lol.

One tonne for a 15ft tri seems a bit heavy to me.

[SeaSpark]

If the boat has no vulnerable engine or electronics in it you could also try to flip it in the water. Launch it from trailer upside down. Float it to a point where you can attach a strong cable to the shore and have a high point opposite of this.

With one side attached firmly and pulling up the other side you should be able to flip the boat, the water will provide a soft landing.

(edit: illustration added)

[Tim B]

Two simple A-Frames will do it. Get four long peices of 3"x2" timber (bigger if needed then drill holes at one end and about half-way down.

Lash the ends with rope so you have two "legs" like an A. Run a block and tackle off the rope lashings. Tie a long peice of rope to the lashings, this will keep the structure stable when it is raised.

Feed another rope through the holes in the middle and tie it off on one side. Now, position the legs to get adequate stability and tie off the rope through the middle of the legs. Raise the frame using the long rope and tie said rope off to the ground.

Repeat for the other frame.

The boat is then simply lifted up, flipped over and placed down again.

Isn't 3000 year old technology marvellous,

Tim B.

[longliner45]

you could trick your friends, tell them that there is a keg involved , thats the way mr. holyoak moved my 32 ft sailboat! with 100 collage students to have a walking boat party,6 people ,3 on each side , can lift a 250lb man with 2 fingers each ,with ease,

[SeaSpark]

How many times did they flip it?

[longliner45]

once, they put it in the cradle. got some pics but I gotta get em from the Holyoaks , yes I thought it was pretty wild myself . but yellow springs ohio is full of free thinkers,,,,,,,,,and everything else, remember thats were Rod serling is from.

[Corpus Skipper]

you could trick your friends, tell them that there is a keg involved

That's always worked for me!

[Hunter25]

Your 15' boat is close to a ton, more like 1500 pounds. I'm guessing the boat is not much more then a bare hull. 1,500 pounds is a lot of beer, but could be done with enough guys.

1500 pounds isn't much for a big healthy branch a chain hoist or large come-a-long. Sling the boat in a couple of tow straps and pick up some weight. You will quickly learn which way the slings need to move to get some balance, then lift it clear of the trailer. Pull the trailer out from under and put her down on the ground. Move the hoist over one of the side rails and adjust the straps so the next lift will cause her to roll onto her side. You might have to use blocking and braces to hold her in place while you adjust the hoist and straps again. 2x4's work good for this. Rock her onto her rail, it is strong enough. Eventually you get to a point where she is almost going to fall over onto the other side. At this point the boat can be balanced easily so that a little push is either direction will cause her to flop over. It will be easy to roll her over in the straps once she's sideways, then let her down to the ground where you can block up the chines pretty square with the ground. Lift streight up, roll the trailer under her and lower her back down. If you know someone with a fork lift, tractor or front end loader you can save some grunt work, maybe a boomed engine hoist in a truck bed or a tow truck boom.

[darkbloom]

Thank you for all the excellent suggestions. Yes the boat is stripped of all engines/windshields/electronics/etc. And according to the Transport Canada plate on it it does indeed weigh 1500 lbs. I have a frame prebuilt that I used for loading my other smaller boat onto my cartop; I think I'll use it in conjunction with ropes and pulleys to suspend it by its longitudinal axis and then flip it in the air. At least that sounds relatively possible on paper... Wish me luck

[VKRUE]

Tim B:
Do you have pic's of what your suggesting, the A-Frame set up?

My imagination fails me, would love to see this.

VKRUE

[Hunter25]

I do not like A frames much, they move around and need a lot of bracing. A branch doesn't need this. A back hoe doesn't need it either. If you do use the A frames then lift it clear of the trailer, remove the trailer then put it back down on the ground. You can adjust the A frames and hoists to lift from one side then. Flipping in the air means fighting gravity. Tilting it up onto it's side allows gravity to work for you keeping the lines tight and does not let the bottom slip out when you have a lot of weight in the air.

[SailDesign]

We regularly (i.e. every boat built) flip decks for 50-plus-footers in the shop with pure people power. 7 or 8 guys each side, lift, put one side down, send other side up, catch, lift, put on poppets. These are 14 or 15 feet wide decks.
A 15ft boat shouldn't ought to be a problem.
Steve

[Tim B]

http://www.milmar.com/images/harvey%20a%20frame.jpg

Something like that. You get the idea for the frames at each end. Personally I'd brace them outwards (ie. Opposite side to the seat in the piccy) rather than hang load off the beam in the middle.

It worked for the builders of StoneHenge, and the Egyptians, so it can't be such a bad solution.

Tim B.

See Also:
http://www.brantacan.co.uk/AFrame.gif
http://oceanica.cofc.edu/CharlestonB...%20a-frame.htm

[safewalrus]

Known as 'Sheerlegs' to old sailors