Swim Platform Weight Limits

[bsb4fsu]

I am planning a mooring system for my 210. I am going to drop about 400-500 lbs of concrete slabs down in 40 feet of water. My plan is to drop it in 2 pieces off my swim platform. I will protect the swim platform with plywood. My questions are:

1) How much weight the swim platform will hold?

2) Is there any difference between having 3 people weighing over 400 lbs standing on it verses having a 200 lbs concrete block and 1 person on it?

3) Does anyone know the calculation for how much weight is needed to hold a 210 in 30-40 mph winds?

4) Does anyone have any other ideas on how to drop that much weight 50 feet off shore in 40 feet of water depth?

[Blue Ski]

Answer to questions 1 through 4: If possible, I would rent a pontoon boat.

[msbowhunter]

Tie a short rope to something that will float the concrete, drag it to your location and cut the rope. Maybe use couple old life jackets to float it or better yet, put it on a tube. Wont really matter if it damages the tube, they are no good anyways!

[bsb4fsu]

Tie a short rope to something that will float the concrete, drag it to your location and cut the rope. Maybe use couple old life jackets to float it or better yet, put it on a tube. Wont really matter if it damages the tube, they are no good anyways!

Agreed on the tube ("no good anyways"). I though about doing it this way, with the floats. Probably the best way to go.

[swc5150]

As far as weight, no problem. There's no posted weight limit, but they can easily support a couple 250lb guys - I've seen that in person.

[AirTool]

I thought the platform limit was 400 lbs. Note this would be total over the platform....not 400 point load outboard of one bracket.

[AirTool]

For the tube, calculate the weight of it filled with water. It would need to weigh more than the concrete or it won't float.

I suspect it would be pretty easy to take it out on a tube as long as the seas are smooth.

You could even:

deflate the tube on the shore
cover it with a tarp
build a form with 2x6
place your concrete mix
insert some bent bar for tie down
let it cure
inflate the tube
tow her to site
de-ballast the tube and let the cement go

I'll let you investigate what permits are required.

[swc5150]

I didn't realize the platform had a specific weight limit, but it's good to know. With that said, I wouldn't be afraid of putting 2 200lb weights on the back for a short time. These boats are so incredibly strong, I just don't see an issue with it - not that I'd do it over and over again, but no trouble with a one-time deal. AT makes a great point on the permit issue. That would be my biggest hang up. Pulling those weights from 40' down would be a lot harder than putting them in!

[NCH2oSki]

Just a thought on this based on experience with our mooring bouy in our cove. Use chain for the first 5' or so, and I ran a piece of rebar through the chain and then pored the concrete into the form. About half way up or so connect a sub bouy that will float the cable in case your surface bouy is destroyed. I have an inner tube section filled with great stuff for my sub bouy. I'm not a 100% sure it will float all of the cable from below the sub bouy to the concrete.

I watched a Jack Axx run over my mooring bouy last week and everything I had sunk to the bottom. Good thing I have a friend that is an experienced rescue and recovery diver, and he was able to find my concrete anchor. I did not have a sub bouy for him to find that time, but do now. Somebody may have a better idea, but this is what we came up with on short notice. Our mooring bouy had been there for 3 years before this happened. (it wasn't a permitted buoy so I couldn't raise to much stink about it.)

[HS]

I have an older copy of Chapman's and in it is a diagram for a mooring based on a large mushroom style anchor, chain, swivel, riser, float and mooring pennant. I'd have to look to see if it has recommended weights for the mushroom anchor.

In So. FL there has to be some boat yards that provide these set ups and would be willing to help you with your set up. But I thought you had a lift; is your collection growing?

[DanielC]

This is a plastic barrel I cut the top out of, and I welded the steel frame in the barrel.

After the frame was made inside the barrel, I took it to a concrete pouring shop, and had then put about a 1/4 yard of concrete in it. I calculated the weight at around a thousand pounds.

After the concrete had set a day, I went and got up the barrel, with concrete, set in the back of a truck with their forklift.

I then drove the truck near where we wanted the anchor. The anchor was tied to a tree, and I drove the truck out from under the anchor. The anchor was then hooked up to our ski teams twin rig, and the boat drug the anchor into position.

[AirTool]

This is a plastic barrel I cut the top out of, and I welded the steel frame in the barrel.

What was the volume in gallons of the barrel?

[DanielC]

Just your standard 55 gallon barrel.
Locally, it cost $60.00 to get the barrel filled with concrete. It could have been done by buying "premix" bags at a local home improvement warehouse, but them there is the time to mix the concrete, and the extra cost to just have it filled was not worth the savings.
However if you have a fair amount of old broken up concrete to take up some of the volume, it may be worth the effort to fill the barrel yourself.

Since putting the barrel in about two months ago, our dock has stayed exactly where we want it. We use our dock for starting show ski acts, and it is important that the front edge stays perpendicular to the shore line, so acts can take off from the dock parallel to the shore line.

[bsb4fsu]

For the tube, calculate the weight of it filled with water. It would need to weigh more than the concrete or it won't float.

I suspect it would be pretty easy to take it out on a tube as long as the seas are smooth.

You could even:

deflate the tube on the shore
cover it with a tarp
build a form with 2x6
place your concrete mix
insert some bent bar for tie down
let it cure
inflate the tube
tow her to site
de-ballast the tube and let the cement go

I'll let you investigate what permits are required.

I like the idea for the tube and deflating it once in position. Even better idea to inflate it under the concrete block.

[bsb4fsu]

I have an older copy of Chapman's and in it is a diagram for a mooring based on a large mushroom style anchor, chain, swivel, riser, float and mooring pennant. I'd have to look to see if it has recommended weights for the mushroom anchor.

In So. FL there has to be some boat yards that provide these set ups and would be willing to help you with your set up. But I thought you had a lift; is your collection growing?

Would it be possible to get a faxed or scanned copy of the Chapmans diagram?

I do have an Air Dock lift for the 210, but I am in the market for a 196 to add to the stable.