Boat Flipping + Hull Flexing

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Boat Flipping + Hull Flexing

Postby tomodda » Tue Jan 29, 2019 2:59 pm

Pt. 1

Hi Folks:

For anyone's future DS-flipping adventures, I thought I'd document what I did to flip my DS1 here. Also, I want to discuss what I observed on my own hull re: flexing, damage, and softness. I've got a few photos, so I'll do this in a few posts as time allows. Happy to answer any questions and I'll take any and all suggestions!

First, let me set the scene - I bought DS1, Hull #37 in August, sailed it some, and am now taking advantage of winter and a friend's garage to do a refit/refurbishment and painting. Speaking with P.O., I don't think anything has been down for #37 in about 20 years, so it's beyond time. I used Xmas break to strip out all the hardware and paint the topsides, and now it's time to flip and do the bottom.

I had to plan for doing this as a two-man job - me and friend with garage/barn - due to the usual logistical nightmare of cajoling other friends out to do any actual work. :roll: Let's call my buddy "Moose" - he's 6'3", 250 lbs, solid construction-worker muscle. Me? I'm 6'1, also 250lbs, most of it is in my shoulders and legs, not gut (although I'm getting there). But I don't sling roof tiles and I-beams for a living. Also, I've got 12 years and one recent heart attack on Moose. I know my limitations, I can do sharp short bursts of effort but not sustained lifting. So, for my two man effort, count Moose as 1.5, me as half. With all that in mind, chain hoist from a ceiling beam and a rolling tackle - continuous loop of line around the midships - was the way to go. And it's been documented here in the forums as a "Two man job," so this oughta work....

More to follow in Pt 2.
Last edited by tomodda on Mon Feb 04, 2019 11:53 pm, edited 1 time in total.
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Re: Boat Flipping + Hull Flexing

Postby tomodda » Mon Feb 04, 2019 11:50 pm

Flipperama _ Pt 2.

Stupid me, I didn't take any before- or during-flip photos, I just have an after-flip photo. In all the excitement I forgot to take a photo of it right-side up and hoisted in the air, and then I was too busy trying not to get smooshed by my own boat to care about taking photos during the actual flipping. When I flip the boat upright again, I'll ask Moose Jr (an adorable 10 year old kid) to snap some photos. In the meantime, here we are post-flip, floating about 6 inches over 3 handy bales of hay:

Flip1.jpg
Post-flip
Flip1.jpg (177.05 KiB) Viewed 341 times


With the one photo, let me tell you what I did. First, notice the chain hoist at the center of the boat. My buddy Moose was absolutely sure that the ceiling beams on his barn would hold the boat - after all he built the barn! But when we got to Go-Time, he decided to play it safe and put a 4x4 post across a couple of his beams, even screwed it down with some drywall screws. Needless to say, I'm all in favour of the belt-and-suspenders approach to safety. We wrapped a heavy chain around the beam and finished it with a simple overhand knot, then clipped the chain hoist onto the last links of the chain. You can see it behind the garage-door light in my photo. I clipped a good-sized Shaefer single block to the other end of the hoist, I think it's a 5-series, just something I had lying around in the parts bin. Lastly, I tied a 1/4 inch low-stretch line (old jibsheet) around the middle of the boat, in a continuous loop. Some notes:

-I had to readjust this rig about a dozen times. Even though my line was relatively low-stretch, on every test-lift I'd run out of chain-hoist space (the hook would reach the pulley) before the line started lifting the boat. The loop would stretch, all I was doing was taking out slack. I knew that i had to have enough space in the loop to flip the boat - i.e. it couldn't just be at deck height - but how to judge how high and account for stretch? Trial-and-error... in the end, I tied my loop about a foot over the deck and once I cinched up the chain hoist it had stretched to 2 feet above the deck, enough to flip it inside the loop.

-I planned to flip the boat to starboard, so counter-clockwise if you are looking at it from the bows. Which meant that I tied the loop with the knot (a doubled sheet bend) right up against the starboard side of the block. After flipping the boat, the knot wound up on the port side, as you see in the photo.

As I said, I believe in belt-and-suspenders, so I put a long ratchet strap under the stern of the boat - more or less at the end of the seats - and another strap up front, in the middle of the foredeck. I figured that this would keep the boat level fore-and-aft while we flipped it, no slipping out of the loop and we could concentrate on rolling instead of tipping over. I also figured I could loosen the straps a bit if they were causing too much friction when we flipped the boat. In the end, the straps were crucial, not only for flipping but also lowering the boat onto the bales. Again, some notes:

-The rear of the boat is way heavier than the front. Wider + benches + the aft locker, it's heavier. Have no idea how much, but I can barely lift the bow off the trailer (squat, grab, lift), no way for the stern.

-The aft strap was wrapped a few times over a beam and then attached to itself with the ratchet to port as high as I could comfortably reach. I made two mistakes. Mistake #1, I originally put the ratchet too low, so when I lifted the boat there was no space to lever the ratchet over. Worse, mistake #2, I used a crappy ratchet strap that I got from my movers years ago. Don't do that, the ratchet couldn't comfortably take the weight of the boat without unspooling, it had no safety notch (an extra notch to rest the bail lever, so you are not depending on the ratchet alone while under load), was too short (I had to jury rig it with dock line), and the strap wound up wrapping around the ratchet and getting stuck. Moose lent me his 1500-lb rated construction ratchet, it was perfect. "Where did you get this?" "Home Depot, 30 bucks". Doh, says me! Swapping ratchet straps while the boat was already in the air was "interesting." Save yourself the aggravation, spend 30 bucks.

-The fore strap was not a ratchet strap, it was simple a strap with two hooks. I wrapped one side (port) over a beam and the other side I attached to a bit of line that I fed thru one of my ratchet blocks (thank you again, GL!). The bow is MUCH lighter than the stern, I knew I could lift it by hand, so I figured I could lift it with his 1:1 hoist and the ratchet block would hold it from falling back down. Test lift.. and I was right, worked great. When I wasn't lifting or lowering the bow, I just tied a loop of the loose end of the lifting line over the strap hook. A little hard to see in my photo, but it's the yellow strap up front, and the ratchet block (brown) is to the left.

-One fly in the ointment, the boat was not at a right angle to the two straps. I had to put the boat into the barn at a slight diagonal, the straps are parallel to the ceiling beams, so naturally the boat is at a slight diagonal to the straps. Caused some trouble, but still worth having the straps.

So, on to how we flipped the boat. I lifted it off the trailer from aft to front, ratcheted the stern to lift it off the bunks - just enough to see daylight, then chain hoist in the middle, then bow lift until it was level. Repeated twice more, I think I lifted two inches at a time to get it to 6 inches over the bunks. Pulled out the trailer, immediately placed three hay bails under the boat - two at the stern deck, one at the bow - for insurance/peace of mind. Then I took the boat as high as it would go , maybe another 3 inches. There was very little vertical space, the ceiling was maybe 10 feet up, but the chain hoist rig took up 3-ish feet and the boat is 6 feet across, you do the math on what happens when it's sideways. So now the flipping. I knew that I could get the boat up to 45-degrees roll by myself, simply by pushing down on the starboard rail. More than that required Moose to help me out. Haaaaaaalp!

I really thought that we'd just flip the boat by grabbing it by the stern and bow (one of us at each end) and flipping, like flipping a mattress, just bigger. In a word, no. Too heavy, too little space, too many weird vectors pulling from the two extra straps at a diagonal. So Moose told me to brace the boat on the starboard rail (now down low, boat was tilted over 45 degrees) and he just squatted under the port side of the hull and bulled it over to vertical - 90 degrees. Of course, now it was unstable as hell and tilting slightly aft (remember, the rear is way heavier). We could have used a third man to cinch the rear strap, instead we kicked one of the hay bales into place to hold the rear corner. And I put my shoulder into the boat and prayed while Moose ran around to my side (starboard, actually the "top" of the boat as it was 90 degrees on it's side). Let me get out the tiny violin for a second, I survived a heart attack 3 years ago, big lifts and deadweight squats ain't my thing anymore, so I was VERY glad when Moose got over to my side to hold the boat. As a side note, if I hadn't been putting in gym hours and doing some boxing in my old life, I probably wouldn't have survived the heart attack at all, so it evens out. Get your exercise! Anyhow, now it was relatively easy to ease the boat down to the flipped position. Except for the moment of excitement when the loose end of the hoisting chain got caught in the centerboard lever, ooops. Only note here being that the low back corner was sitting on a hay bale, we had to make sure it scooched over as we finished turning the boat. Some judicious kicks did the trick. Once level again, said back corner lifted itself off the bale again.

Post-flip, I adjusted the front and back straps to get the boat fully level fore-and-aft. It wasn't too far off, less than a foot low in the stern, but I'm anal that way. Then it was a "simple matter" of lowering it onto the bales, a little at a time, loosening the aft strap, then the chain hoist, then the fore strap. At least that was the plan... small problem with the aft strap, it's a ratchet, right? So as soon as you open it under load it unspools all the way till its slack! A little scary when it happened, but in practice it dropped only some 6 inches then the boat was resting on the middle loop and the fore strap. So again I leveled off the boat, here's where my ratchet block setup on the fore-strap came in handy, then dropped the aft another 6 inches. Rinse repeat, I think 4 times total.

Ta-dah! Boat resting upside down on bales, took about 3 hours total and I only needed Moose for 5 minutes (he does have a life outside my boat craziness). Photo:

IMG_20190127_154335-800x600.jpg
On Bales
IMG_20190127_154335-800x600.jpg (227.03 KiB) Viewed 333 times


Eagle has landed!


Thanks for reading, assuming you got thru everything above. Happy to answer any questions or take any suggestions for the flip back to upright.
tomodda
 
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Re: Boat Flipping + Hull Flexing

Postby GreenLake » Tue Feb 05, 2019 1:02 pm

Nice write-up.

Reading this and comparing with my own efforts, I'd say that flipping in the air may have made it harder. Every time I flipped my boat, some part of it was resting on solid ground or on padding (Some of the times while also held in a loop).

Last time I just lowered it to the floor (by "launching" it, but your method would have worked as well) then flipped it over by "rolling" it w/o any overhead support. That does require having more than two boat widths to work with for space.

Now, I can lift the back of the boat enough to straighten it when it's askew on the trailer; never thought that was unusual, because I'm not into weight training . . .
~ green ~ lake ~ ~
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Re: Boat Flipping + Hull Flexing

Postby tomodda » Tue Feb 05, 2019 4:06 pm

Hi GL!

Agreed, flipping the boat in the air added complexity. Better would have been to dry launch it and flip it with 3 strong guys, or using the mast to careen it. But being inside a barn in 20 degree weather made it worth the extra effort. Also, I don't have 4 strong guys that I can get all together in one place at same time, even with money/pizza/beer to entice them. So, all things considered, I was happy that I was able to flip it 95% by myself. Especially considering that I can barely hoist two bags of groceries anymore, let alone lift the back of a Daysailer! So, I wrote this up hoping that it would help anyone else who needs to flip their boat "the hard way."

Tom
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Re: Boat Flipping + Hull Flexing

Postby GreenLake » Tue Feb 05, 2019 7:05 pm

Your method of lifting and continuous loop, but let it touch the floor / padding. What do you think?
~ green ~ lake ~ ~
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Re: Boat Flipping + Hull Flexing

Postby tomodda » Tue Feb 05, 2019 9:59 pm

I was afraid of crushing the cuddy roof. Plus - pride goeth before the fall - the topsides and cuddy had a brand new coat of paint that I didn't feel like scratching. That being said, I kinda wound up using a support in that I needed the hay bale at the aft corner. Next time, I'll plan it out with hay bales intentionally giving me extra support. For that matter, I think I can turn the boat by myself if I rig an extra pulley and a safety guy. Just have to do some thinking.

In the meantime, I've been sanding, filling in scratches and dings, and sanding some more. Oh joy! At risk of boring everyone to tears, I have a set of photos of my hull touchups, mostly where and how the gelcoat cracked. As I wrote in another section, the killer for the hull are the trailer bunks, I had a network of cracks radiating out from those, especially towards the front. Time for longer and wider bunks, so yet another project :)

Tom
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Re: Boat Flipping + Hull Flexing

Postby GreenLake » Wed Feb 06, 2019 1:44 am

If possible, you should try to restore the strength in the hull. If you look over the older threads you find one called "The Core Project". It describes strengthening the hull by lining with core and an additional inner skin.

Failing the desire or wherewithal to undertake something that big, perhaps adding a second set of stringers is advised.
~ green ~ lake ~ ~
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Re: Boat Flipping + Hull Flexing

Postby tomodda » Wed Feb 06, 2019 8:19 am

Yes, I've been reading "The Core Project" with a mix of horror / fascination. Admiration too! But it's too much for me, if anything I'm thinking of doing some reenforcement (a mini-core) from the chain plates down to the keelson. That's we're the worst stresses and flex are. Next winter's project.. Maybe.
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Re: Boat Flipping + Hull Flexing

Postby GreenLake » Wed Feb 06, 2019 11:51 am

yeah, totally get you.
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