Building a Work Boat

Hi I have taken over a mooring buisness in my local harbor and the equipment im using is just not cutting it. I would like to build a deck barge or find one pre made (whichever is cheaper). I have over a hundred moorings that i remove/ install yearly ranging from 250lbs to 1000lbs. Im wondering if anyone knows the best way to do this. My thoughts were a 24' by 14' Heavy duty deck sitting on plastic modular pontoons. Then have a 4' x 4' hole in the middle with an A frame or Gantry with a 10,000lb winch set up. I would like to have this be self propelled . Please if anyone has any ideas or have something that would work for my application that you would like to sell please let me know thanks

 

A first thought is that a simple pontoon catamaran with a "crane" and an electric winch would do the job. That would be a very simple boat with 2 boxy hulls, 2 small outboards engines (thus very maneuverable) and a central hole so no problems of stability while lifting a 1000 pounds mooring.

A such boat made in plywood and hot dipped galvanized mild steel for the "crane" and beams would be inexpensive. You are not far from the truth; the lone problem is that plastic modular pontoons will have problems of rigidity (or stiffnes) and will need a lot of bracing to keep them together. Boxy hulls in plywood or GRP will be less expensive and stronger specially in choppy conditions. The other problem is to have enough clearance beetwen the floor and the water so can pass over the buoy to catch it, and plastic modular pontoons are definitely too low, and maybe will lack of buoyancy, unless you go for a special structure. Again it's easier with catamaran hulls.

As you have not special requirements of speed, the whole thing remains very simple.

 

You could start with plans for these then widen the deck and perhaps deepen the pontoons.
http://www.boatdesigns.com/products.asp?dept=169

Steve

 

How many moorings do you haul at one time? Do you work on the mooring on the barge?

Regards

 

Thanks everyone for helping. First of all I wanted to use 36" diam poly pontons which would be large enough and give me the clearance. With the setup I have now I pull and have on deck around 4 moorings at a clip. Then go in and offload them or vice versa. If they are smaller moorings i would like to have around 6 to 8 at a time on the vessel. Speed is not a issue as loong as its not slower than the one I have now (top speed 3.1 knots)