Floating dinghy dock

[Alok]

My Tomcat is kept full-time in a slip.

I have a 10-foot inflatable dinghy with a 5 HP motor. I would like to keep the dinghy in the slip next to the Tomcat.

I need to build a floating dock to keep the dinghy on. I would appreciate any opinions concerning my plans:

1. Build a frame from marine grade plywood (any suggestions for a different material?)

2. Attach closed-cell foam blocks to the bottom (how should I attach the blocks?)

3. The dinghy and motor weigh about 125 lbs. Add one person on the dock (200 lbs) + the weight of the wood, the total flotation needs to be about 400 lbs.

A cubic feet of water weighs about 64 lbs. So, I will need about 7 cu. feet of foam - is that correct?

4. Put astroturf or outdoor carpet on the top?

If any of you have built something like this, I would appreciate advice/comments/pictures.

Thanks!

[gljjr]

The ones I helped build when I was a kid (read about between 8 and 10) were made out of treated 2x8's on the sides with treated 2x6's for the decking. The foam blocks were simply held in place by tension with the 2x8's and the weight of the docks.

I think you would find that the plywood would end up being very slippery and outdoor carpet gets nasty. Astro turf would work but you'll forever be shooing ducks and geese off of it! Even with 2x6's the docks will get really slick at times. The swim float had a plywood top and it needed to be painted every couple years if I remember correctly. Even then it didn't last as well as the docks with the 2x6 decking.

Sorry, I don't know how much foam you would need to support it all.

[thataway]

I tend to agree with Gary. One problem is that most areas will discourage or not allow styrofoam floatation unless it is enclosed in plastic. The way it was held in place was with plastic strapping. The encased material has molded in places for lag bolts. Marine grade (5%) treated 2x 6 or 2 x 8 for the frame and some cross members in the center--ie if the dock is 6 x 10, the frame would divide the foam into four 3' x 5' sections. For floatation you need to float the weight of the wood frame, foam, fasteners as well as the decking. See below for corner plates which are high quality galvanized. I would use Trek or one of the synthetics for the deck--it is much nicer and lasts much better than plywood or astroturf etc. If you want to put some dacron foam filled bumper material on the edge you bring the inflatable up on, that would help.

Marine ply is expensive, and unless coated with epoxy is not that good a material to leave in the water.

There are also plastic drive on docks--which might be a better answer.
For example the "jet dock" http://www.jetdock.com/univ_pwc_dock.asp

Floats which are plastic, with foam centers like these are a better answer:
http://www.premierfloats.com/Premiermaterials/dock_floats.htm?src=overture&ovmtc=content&ovadid=1907351522

Overtons also has all of the materials you need, including the floats:
http://www.overtons.com/modperl/product/catalog.cgi?r=browse&aID=25&cname=Dock-Mooring

Another answer may be the Boat Lift Wearhouse "Floating poly dock system"
http://www.boatliftwarehouse.com/docks/shoremaster/poly_dock.php
Boat lift Warehouse also has a "Shoremaster PWC dock"--
http://www.boatliftwarehouse.com/docks/shoremaster/pwc_dock.php

[starcrafttom]

for cost savings find your self a local pool or boat maker and ask about plastic 55 galon drums. I delivered these in apast job. They are always tring to get ride of them. They are water tight and last for every. Once you have them just build your decking out of your choice of materials around the drums while they are on their sides. A good plastic or fiber strap should hold the drums under the decking. Aalot cheaper them foam and does not rust like steel.

[Alok]

Thanks, all- I knew I would get some good ideas!