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PostPosted: Mon Dec 09, 2013 1:15 pm 
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Would it be safe to assume that if the factory carrying handles were designed to support the weight of the kayak (and perhaps some gear) when PEOPLE lift the kayak, that the handles would be an appropriate point to TEMPORARILY suspend the kayak from a lifting device, such as davit cables?

Is there some sort of engineering or mathematical wizardry that I am not privy to that would cause one to believe that a mechanical lifting mechanism is somehow different than people lifting the same weight from the same spot?

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PostPosted: Mon Dec 09, 2013 1:47 pm 
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I believe the problem would be in trying to support the kayak for longer periods of time via the handles. They're not ideally spaced for supporting the hull weight for more than brief intervals.

Somebody from Hobie will almost surely chime in here.

...............


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PostPosted: Mon Dec 09, 2013 2:43 pm 
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Normally, you would almost never "suspend" a loaded boat by the handles. They were not designed for this. You would drag it, wheel it or lift half the weight for a short time.

Straps would be stronger and much more stable way to do this on a regular basis.

So, what kayaks are we talking about?


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PostPosted: Mon Dec 09, 2013 7:30 pm 
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NOHUHU wrote:
Normally, you would almost never "suspend" a loaded boat by the handles. They were not designed for this. You would drag it, wheel it or lift half the weight for a short time.

Straps would be stronger and much more stable way to do this on a regular basis.

So, what kayaks are we talking about?


I agree whole heatedly with your statement. What I'm trying to accomplish is to carry my oasis tandem using the dolly, to a davit that is mounted to my dock.

I would like to attach the two carrying handle to two cables that in turn, connect to a block on my davit. I could then lower the kayak the 5-8 ft to the water where I could board and remove the cables.

I can't imaging the "suspension" would be any longer than maybe 2 minutes and I guess I don't understand how that would be any different than two adults each lifting one end of the kayak, using the same handle, as they carry it to the beach or car....

I agree that using straps under the body of the kayak is a better, more supportive technique however, I haven't figured out a way to rig a strap system that would keep the kayak level and not have it slide out do the straps one side or the other.

I've played around with it a little and have come up with what you see below, but it's just not a practical rig. To many connection points to undo once in the kayak.

Actually, as I write this , it dawned on me that once seated in the kayak, I wouldn't be able to reach the hookup on the bow handle !! :shock:

Any suggestions from the engineer types appreciated...

Image

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PostPosted: Mon Dec 09, 2013 8:29 pm 
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flrider :
Now I see your setup, it looks very similar to the crane I mounted onto the hitch on our SUV to lift both our Oasis and our revo kayaks onto the roof. I built it because I tore my back muscles lifting the Oasis onto the roof, and couldn't lift much for about a year afterwards so I built a little jib crane that mounted to the hitch on the back of the car (nothing fancy). I didn't want to have to mess around with ropes and slings either, so I just tied a line to the front lifting cleat, and a second line to the rear lifting cleat. I then took a 4 inch ring and clipped the lines to the ring. I kept all those lines on the boat (never removed them). when I wanted to lift the boat I would just get the ring out of the mesh pocket, usually with one of the lines still clipped to it, I would fish the end of the other line out of the other mesh pocket, clip it to the ring, then hang the ring on the hoist (simple and fast). Since the balance is controlled by the lengths of the ropes, once you have them adjusted you never have to adjust them again (just clip them to the ring). I used 1/8 inch dia paracord (500 lbs test), it all worked like a champ until my back healed up, then I went back to just lifting the boats up.
Of course the boats were always completely empty (and drained) when I loaded them onto the car.
Hope this helps
Bob


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PostPosted: Mon Dec 09, 2013 10:33 pm 
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If you were to incorporate a boom off the davit so that the lift would be more vertical (attaching to each end of the boom) I wouldn't think there would be any unnatural stresses. If you keep the lines secured at the bow and stern handles as fusioneng mentioned, you should be able to attach/detach from the cockpit. 8)


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PostPosted: Tue Dec 10, 2013 11:00 am 
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Roadrunner wrote:
If you were to incorporate a boom off the davit so that the lift would be more vertical (attaching to each end of the boom) I wouldn't think there would be any unnatural stresses. If you keep the lines secured at the bow and stern handles as fusioneng mentioned, you should be able to attach/detach from the cockpit. 8)


+1

Lifting the hull with gear in it or supporting from the handles for more than a typical person could hold it would not be advised. I like the straps idea shown, but not for long term suspension. The less vertical the lift, the more compression caused on the hull, so a boom would help.

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PostPosted: Tue Dec 10, 2013 11:39 am 
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mmiller wrote:
Roadrunner wrote:
If you were to incorporate a boom off the davit so that the lift would be more vertical (attaching to each end of the boom) I wouldn't think there would be any unnatural stresses. If you keep the lines secured at the bow and stern handles as fusioneng mentioned, you should be able to attach/detach from the cockpit. 8)


+1

Lifting the hull with gear in it or supporting from the handles for more than a typical person could hold it would not be advised. I like the straps idea shown, but not for long term suspension. The less vertical the lift, the more compression caused on the hull, so a boom would help.


Well, I guess that solves that..... looks like I'm off to the boom design table....

Thanks for everyone's input..


If someone manufactured a moderately priced ( <$500 ) , simple dock deployment device (DDD), for ALL kayak/canoe type pwc's...
Something that allows you to enter the kayak on deck level, lower it from a seated position and then still be able to raise it, while in it upon return,........they would make a fortune. I'd buy one...

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PostPosted: Fri Dec 20, 2013 11:01 pm 
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Hi Fusioneng
I am very interested in your 'back saver' crane attached to the tow hitch of your SUV.
I have a ladder roller on the rear rack but it is still a bit of a struggle putting an oasis tandem up there.
do you have any pictures of that rig?
Most i have seen would weigh a lot more than the kayak itself

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PostPosted: Sat Dec 21, 2013 7:09 am 
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Croc:
The boat winch that I bought at Harbor Freight for the lift, I re-cycled and is now on my trailer (I think it was around $25 bucks). Here is a pic of the winch on my trailer (look near the front, it's a pretty standard winch).
Image



I started with a T bar hitch receiver that I bought at Amazon.com ( I think it was around $80 bucks), here is a pic of the T-bar receiver.
Image

At the time we had 3 kayaks, one Oasis and two Revos, I tore a bunch of muscles in my back one day trying to lift the Oasis onto the roof of our Denali, (it hurt so much I pee'd my pants LOL). I was unable to lift anything for quite a while, so I bought the T-bar receiver to make it a little easier (previously I had four Malone stinger combo racks on the roof, two pointing forward and two pointing backwards so I would have four support points on each boat spread well apart. We would travel a lot around the country with our camper in tow, if I had to guess we had around 200k road miles with the kayaks on the roof. The Malone stingers were nice because they had a guide tongue that stuck out behind the car for loading.
Once injured, I could no longer lift for a while so I made a simple lift out of galvanized 1 1/2" pipe. Basically it was a 1ft and a 3ft piece joined together by a union. At the top of the 3 ft piece I put an elbow then another 3-4 ft piece of pipe. I mounted pulleys to the sides at the elbow, and at the end of the long horizontal pipe.
I would put the Tbar receiver into the hitch on the car, remove the top T part of the unit, and slide the 1 ft pipe into the top of the open end of the 3" square Tbar at the top (making a crane). I had the boat winch bolted to the side of the T-bar unit. To lift one of the boats I would pull the boat behind the car (sideways right behind the car). I had a 4 inch metal ring with lines tied to the front and rear metal lift padeyes, then at the other end I had stainless clips that clipped to the 4 inch ring. Everything was tied and preset at the balance point of the boat and I just left the ropes attached to each boat all the time, stuffing the ropes into the mesh pockets when not using them.
When I wanted to load a boat I would grab the ring clip it to the ropes, run the winch wire over the pulleys then lift the boat with the winch. Once up over the car I would rotate the winch around and set the boat onto the Malone wings, I would then remove the winch and push the boat forward to it's final position. I would then do the same on the other side with the other boat. Once the boats are loaded I broke the receiver unit down and stuffed it into the back of the car. The whole works ended up working ok and wasn't as heavy and bulky as it sounds. I started to worry about that 90 degree elbow joint maybe not being strong enough so I bolted a 1/4" x 1" x 1 ft piece of aluminum to the side at the corner at a 45 degree angle to re-enforce the 90 degree elbow. Actually on the long horizontal pipe I used two smaller pieces with a union in between so I could unscrew and break down the unit for storage in the back of the car, another reason is they only sell pre-threaded rod up to 2-3 ft lengths at the local hardware, if you needed a longer pipe you would need to thread it yourself (keeps the plumbers employed LOL).
Was it safe (probably not)
could you get hurt if it failed (probably)
did it work (yes, I used it for about 6 months every weekend until my back healed)
Once my back healed we ended up trading in the Oasis for a Tandem Island. The TI was much easier to load onto the Tbar than the Oasis ever was, didn't need the winch anymore so the winch system was retired.
Now if I'm not using the trailer, then I just load the TI onto the Tbar (just like the second picture above). It's actually very easy and fast, since you are only lifting half the weight of the boat at any time (about 45 lbs) it's actually much easier to load than the Oasis ever was because the boat is longer, and there are a lot better hand holds (I honestly can't tell the difference in the weights, the TI is at the most 10 lbs heavier it seems, but way easier to load).

What I do is walk the boat up to the car from behind so the rear is centered behind the car. I then walk the bow to the side of the car so the bow is even with the back wheels of the car. I then lift the front of the boat and place on my head, I then walk forward then sideways a little until I can rest the bow onto the tbar. I then center the boat on the T bar, then go to the back and lift the back of the boat and slide it forward. I actually roll the boat on pool noodles, it actually slides very easily. Then I just strap it down with the AMA's and sails stuffed along the sides. The boat is strapped to the roof rack in two places, then another strap at the T-bar (which is holding most of the weight). I don't do anything else on short trips, but on long trips like our monthly trips to our Key West place I also tie a safety line from the bow to the front bumper (we have no place to keep our trailer at the key West place so we just keep the boat on the roof all the time we are down there, (strapped down with HD motorcycle chain locks of course).
I'm not a big guy at all and my back was broken is a karate tourney when I was 45 (I'm now an inch shorter and my back has never been right since). Personally I find it way quicker and easier for me to just load the TI onto the roof by myself without any winch or anything, but that's just my preference. I'm out there every weekend, and when down in KW we typically go out every day (that means loading and unloading the boat daily), it works for us, that's all that matters, once you get a system down, it's actually pretty easy and painless.
Definitely get the sail set, we have the sails on all of our kayaks and never go out without them (kayak sailing is our favorite thing to do).
Bob

edit:
Oops I just looked at the top pick where I said the winch now resides, when I took that pic I hadn't installed the winch yet (sorry), the winch mounted on that alum brace in front of the bow (it's just a standard boat winch).


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PostPosted: Sat Dec 21, 2013 9:45 am 
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fusioneng wrote:
Now if I'm not using the trailer, then I just load the TI onto the Tbar (just like the second picture above). It's actually very easy and fast, since you are only lifting half the weight of the boat at any time (about 45 lbs) it's actually much easier to load than the Oasis ever was because the boat is longer, and there are a lot better hand holds (I honestly can't tell the difference in the weights, the TI is at the most 10 lbs heavier it seems, but way easier to load).

What I do is walk the boat up to the car from behind so the rear is centered behind the car. I then walk the bow to the side of the car so the bow is even with the back wheels of the car. I then lift the front of the boat and place on my head, I then walk forward then sideways a little until I can rest the bow onto the tbar. I then center the boat on the T bar, then go to the back and lift the back of the boat and slide it forward.
Croc, if I understand fusioneng's description correctly, this may roughly illustrate his description using the T-bar. Even though you have a ladder roller, the T-bar might have some additional advantages since it is further back and easier to place the bow on. It can also be adjusted a little lower, making for less lift height. There are a couple of other ideas here as well.
viewtopic.php?f=71&t=22849&p=100527

I use this lift method also with our Oasis -- works well. The more extreme angle is a disadvantage, but the lighter hull compensates.

You may be able to rig a dual purchase system to your roof rack to make a simple "winch" to slide the boat forward so you have less lift weight on the stern -- if your rack mounts can handle the lateral stress. 8)


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PostPosted: Sat Dec 21, 2013 10:43 pm 
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Thanks for your replies Fusioneng and Road Runner.
I have an old Subaru liberty for transporting the oasis locally so loading is no problem rest it on the boot wing then shove it on to the cradle. When I go away ( and you wouldn't go away without the hobie) I tow an Avan with a Land Rover Discovery so any T- bar that uses the haymen recce hitch would be a huge hassle removing the tow bar, also the weight would be an issue on a long trip. The main problem is the initial lift on to the rear rack and the lowering in a controlled way when unloading. I am thinking another cart fixed to stern to protect the tiller or perhaps some sort of skid (when I put the bit of carpet down it never seems to be in the right spot).
A side loader would be ideal but don't think the 897XT would cut the mustard.
Thanks again for your ideas

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