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Building a Floating Dock?

Posted: Apr 26th, '10, 10:10
by Major
The dock is finally failing and needs to be replaced. The professionals price was $15k so we are looking into doing it ourselves. (dun dun duuun :twisted: ) Have any of you made a floating dock and have any tips or suppliers to pass on? Our old one had the old exposed foam thats a pretty developed sea creature habitat now. I hate to disturb that but dont know how to really keep it. For the rebuild we planned on using the foam filled plastic floats. We are in salt water off the main inlet on a canal. So the area is pretty well protected other than the occasional mightier than thou that doesnt care about his wake.

The size we have and hope to be able to rebuild is 12' 6"x 16' 2". the ramp is tied to the retaining wall on one end and the dock on the other end. There are also two pilings that secure the dock in place. We were going to reuse them. The ramp is currently a wood one but we are considering a aluminum one with wheels on the bottom. One issue with that is we currently keep a 12' john boat on the dock. The added room the wheel movement would take up may cause issues with that. The master plan incorperated a something that could just drive up on like what you see for jet skis and that would solve the issue but we may not be able to add that extra width.

Ive found some "plans" on the internet but who knows if they were sucsessful plans or not. Im also having some issues tring to figure out how high of floats to get since i dont know how to figure out how much they will sink. We launch kayack's from there every now and then so it cant be too high atleast on one side.

Thanks,

Major

Posted: Apr 26th, '10, 15:12
by CaptPatrick
Im also having some issues tring to figure out how high of floats to get since i dont know how to figure out how much they will sink.
A 1 cubic foot sealed container will displace 64 lbs of salt water. Said another way; 1 cu ft container will support 64 lbs at surface level.

Your projected dock size is 204 sq ft. One foot of floatation height would give you 204 cu ft of floatation which would support, at surface level, 13,056 lbs of gross weight, (equally distributed & free floating).

If the gross weight of the dock, jon boat, several people, dock box & contents, ramp and a fudge factor of 1,000 lbs came to 3,600 lbs, 204 cu ft of floatation would theoretically have your dock surface at about 8.7" above the surface of the water.

For every additional 1 inch of floatation height, (based on your 204 sq ft of dock surface & 12" of floation height, and 3,600 lbs of gross weight), you'll be another 1" above the 8.7"... Using a 24" flotation height, your dock surface would ride about 20.7" above the water line.

You should have at least 2 heavy pilings that capture the dock. These usually project through the dock surface and have 4 rollers per piling for the dock to ride up and down the pilings. Allow room for a couple of inches of free space over the maximum diameter of the pilings between opposing rollers.

Posted: Apr 26th, '10, 15:23
by TailhookTom
Capt Patrick: You should have been a professor (maybe you were), cause you have the ability to take something highly technical and let schmows like me understand it! We are lucky to have you running this site!

Posted: Apr 26th, '10, 17:06
by Major
First of all CaptPatrick you should really add a paypal donation link.

Thanks for the great explination as usual. Those figures and info will really help in buying and building the parts.

I wouldnt mind coming to a fiberglassing or boat constructing class from a few of yall on here if you ever had a boating tech get together. A few of you could easily charge for that. I paid about $75 to go to a silencer/suppressor shoot and seminar and didnt even shoot. Not to mention gas, hotel and food. Atleast at a boat tech seminar i could take a little more home i didnt already know.

Posted: Apr 26th, '10, 18:45
by scot
Captain Patrick you would be handy on a salvage project.

Posted: Apr 26th, '10, 20:07
by Tony Meola
http://www.mercoboatdocks.com/

Try this link for ideas and to price out material you might need.

Floating Dock

Posted: Apr 30th, '10, 09:05
by FWHaas3
I am also in the process of building a floating dock. I purchased all of my hardware from dockbuilders.com, located in Florida. The stuff just arrived two days ago and it is really heavy duty. They have an excellent website.

I also purchased my nuts and bolts from an outfit in Rochester, NY. They were less expensive than dockbuilders.com for the nuts and bolts.

Go onto the internet and search floating dock hardware and these two outfits will come up near the top of the list.

they will also provide suggestions on the size and number of floats you need for the size dock you are building.

I am building a 4'X18' dock, which is obviously smaller than the one you are undertaking.