My DIY floating ramp for docks

[Mr Bojangles]

Ok, I'm going to do the air pump. I did some digging and the hydrohoist uses just a blower for the air pump and I have one on my air dock I can tap off of. It looks like I will now move the drum back and on the bottom drill a 1/2 hole and on the side with the 2 inch fitting I will tap it and put a air hose line that will go to a valve that will let me vent the air, and then a fitting to let me put the air hose on and fill it up. I should hopefully make loan and launching easier since it will be lower. So are you sure hydrohoist just puts a small hole in the lowest point? I do see in the vids that when bubbles come out the bottom it's full. It seams like it would work, I just want to make sure before I drill a hole on the bottom of the tank and hope there is no slow air leak from the tank plugs otherwise it will slowly leak and sink when I'm not there

 

[QuickMick]

well do what I did, marry someone who has parents who live on the water and make sure they are cool with you taking up their water front with all of your toys and your set!

Do you have a sister n law thats single?

 

[Mr Bojangles]

Do you have a sister n law thats single?

I do! But she is 14 if your into that sort of thing

 

[vitalikol]

I do! But she is 14 if your into that sort of thing

He can wait 10 years or soo ....

 

[QuickMick]

He can wait 10 years or soo ....

Naaa she has to have a job, and she wont for another 20.

 

[eeerieski]

Boyancy of different size drums:
55gal h2o 459lb
35gal h2o 292lb
55gal salt h2o 470lb
35gal salt h2o 299lb

to evacuate a 55gal barrel of h2o in one minute would require a minimum of 2psi at 8CFM. If you had a 10ft ramp hinged at one end and a 35gal barrel at the other an average stand-up on the end would be capable of submerging the barrel. With the ski winched up the barrel should be more than half out of the water. Given this info and proper balancing you should be able to just barely keep the barrel out of the water when winched up (pre-fill partly and seal barrel) and easily submersible when launching or retrieving. With this method you should not need air lines or any special equipment to launch and retrieve single-handedly. If you put on longer boards and keep the barrel at the same place you should be able to atleast get the ski on the rails most of the way from in the water and winch it up the rest of the way.

 

[Mr Bojangles]

That's a good read. Right now the ends of the bunks are 1 inch out of the water , but if I move the barrel where it's easier to get on, the wood will be in the water and since it's salt, I will have barnicals in two weeks time. I'm still going to try the pump. We will see how it goes

 

[Peter123]

Boyancy of different size drums:
55gal h2o 459lb
35gal h2o 292lb
55gal salt h2o 470lb
35gal salt h2o 299lb

to evacuate a 55gal barrel of h2o in one minute would require a minimum of 2psi at 8CFM. If you had a 10ft ramp hinged at one end and a barrel at the other an average stand-up would be capable of submerging the barrel. With the ski winched up the barrel should be more than half out of the water. Given this and proper balancing to just barely keep the barrel out of the water (pre-fill partly and seal barrel) you should not need air lines or any special equipment to launch and retrieve single-handedly. If you put on longer boards and keep the barrel at the same place you should be able to atleast get the ski on the rails most of the way from in the water and winch it up the rest of the way.

Excellent, you saved me a Google search.

 

[Mr Bojangles]

ok, this is what I am planing tomorrow as of now. Since I have to holes in the side of the tank, I am going to use them to test it out before I drill something perminate. With this setup I dont plan on it getting 100% of the water out, but just enought. What do you all think?

 

[grezzmky]

Lake of the Ozarks is NASTY so we use Hydro hoists on all the boats. The pumps are just out of a Vacuum cleaner.

 

[grezzmky]

ok, this is what I am planing tomorrow as of now. Since I have to holes in the side of the tank, I am going to use them to test it out before I drill something perminate. With this setup I dont plan on it getting 100% of the water out, but just enought. What do you all think?

All you need to add is a 'T' and a valve to the red air line to let air out to lower it

 

[Mr Bojangles]

Opps, forgot that in the pic, but yeah it's going to my air dock control box that has the vacuum air pump in it and a ball valve. So we will see tomorrow hopefully

 

[Peter123]

I'm not sure why you have that "water in/out" valve. All you need is a few holes drilled in the "bottom" of the barrel.

The hose will go up to your valve where you have it so it's closed, venting to the atmosphere or positive pressure.

When it's closed, the amount of air you have in the barrel will remain. It's like hold a glass upside down and pushing it under water. The bottom is open, but since the air won't go down, it remains.

When it's open to the atmosphere, the air will be pushed up through the hose and water will enter through the holes in the bottom causing the barrel to sink.

When it's on positive pressure, the air coming into the top forces the water out the bottom and the barrel to rise.

EDIT: Sorry, I just skimmed your post and mainly looked at your drawing. I thought (until I reread) you were planning to attach a pump or something to push water into the barrel through the bottom tube in your drawing. I'd still not bother with that bottom hose/tubing in the lower hole since it could clog relatively easily (even if just partially) and restrict or slow the water entering the barrel and preventing it from sinking or at least making it slower than it would otherwise take. And of course, the smaller the ID of the fill/release hose, the slower it will take to evacuate the air and lower your ski.

 

[eeerieski]

If you unscrew one of the plugs and make sure that barrel is rotated such that the hole is at the bottom then you don't need to drill any holes in the side thus ruining any future airtight capacities of the barrel. The air inlet/purge should be installed in the opposite hole/plug on the now top of the barrel.

 

[Peter123]

The reason I'll be going with the bottom drilling instead of just using the lower plug is because I plan on going with the smaller barrel and don't want to lose any of the lift capacity by using the existing plug. Additionally, since it looks like I can pick them up for $10 to $15, I don't care if I have to buy another in the future for an airtight application.

 

[Mr Bojangles]

ok, a update! I went out today and set it up, I drilled 2 1/2 holes in the bottom and ran a tube with a ball valve up to my pump, and it worked! Now it takes quite some time to sink, so I am debating on drilling another hole, but it inflates quick.

But there is a new problem.............

as you can see in my pics, I had the barrel held down by rope, and there was a flat spot on the tank, now with the air being able to leave and enter, it makes it very unstable, to the point where the barrel just tilts a bit and shoots out, dumping the ski off. I tried tying it some new ways and it didn't work, so as of now, the barrel is sitting on the bottom of the canal completely sunk with the last inch of my ski in the water, so I need some ideas to lock it in place, and the only way I can think of it to run some wood like a 2x8 on the top of the barrel and try and put the barrel in some sort of cage. any ideas?

 

[eeerieski]

On our dock we used plastic strap wrapped around the barrel used for hanging pipe from joists in basements, works well then the dock holds the barrel and the straps are essentially loose...Probably won't work in your situation. You could use metal pipe hanger strapping but I am not sure how that will hold up in the brackish water. What I would do is make the holes in the bottom of the barrel large enough to get your hand into, build a saddle on the end of your ramp for the barrel and bolt the barrel to the ramp with galvanized lag bolts.

 

[Cannibal]

I'd install some eye bolts with fender washers from the under side that line up with each bunk and then tie a rope forward and backward to keep the barrel from rotating. Since you have a big hole in the bottom you should be able to reach in and tighten the nuts for the eye bolts.

I'd also create a "cradle" at the top with some crescent shaped pieces to give the barrel a better "footing". Think of how wine barrels are placed on racks to age, just upside-down.

 

[Shifty]

Buy some 3/8" Stainless all-thread and bend to make your own "U" Bolts to strap the barrel to the ramp. Drill holes in your runners/frame and fasten as shown in the awesome Paint drawing. I would punch three or four 2-1/2" holes in the bottom to speed deployment, maybe add some ballast in the drum with some rebar laying accross the bottom (corrosion/rust). The vent valve and hose leading to your drum are just as important as the holes in the tank. If the valve and hose are too small in diameter, you can't move air fast enough. You could also cast some concrete weights to hang off the frame.

 

[Peter123]

If I understand your problem correct, just get some marine plywood and cut a round area out of it to match the top of the barrel (x2) and then bolt these on to your existing bunks and then use a strap or rope.