Building a dock

[Hogtamer]

Make sure it has a ladder into the water in case someone falls in.

[Hogtamer]

Make sure it has a ladder into the water in case someone falls in.

[Menner]

SnowWolfe
I am kinda simple minded so I would approach it this way
6x30x8.3=1494 lbs of buoyancy 9=2241 lbs so if you load 1494 on 6 barrels you would be floating but right at the surface of the water so I would work on a 50% basis I would want about half of the barrel out of the water and I would want the wood of the dock to stay out of the water.
Having said all that, from what I gather this is a private pond with no tidal rise or fall and no motor boats only seasonal water table changes that will be slow changes so and I would assume nobody would be venturing out on the dock in the middle of a storm so waves should not be a problem
I would assume you will use treated lumber (that mess is heavy, a calculator I found said treated 2x4x6' is 10.5lbs 2x4x8' is 14lbs 2x6x8' is 22lbs) and width is your friend for stability I would make it at least 6' wide and probably 8'wide. At 6'x14' you are going to have approx. 700lbs in lumber (Treated) At 8'x14' Approx. 900lbs
going wider will not cost you that much more and would be well worth the stability just keep the barrels as far out board as you can for maximum pontoon effect, I would consider 9 barrels and being fresh water a couple pieces of 1 1/2" galvanized pipe driven into the bottom and a couple of 2" pipe straps would hold it in place ( put caps on the top of the pipes or the hornets will love you)
Just my thoughts we have built a couple using 55gal Drums and they are a lot more stable if the barrels are close to 1/2 submerged.
Tony

[snowwolfe]

Make sure it has a ladder into the water in case someone falls in.

If anyone falls in they can walk swim, paddle, or pull them self along the dock to the shore and walk out, lol.

[Ballistics in Scotland]

If it was me I would use 2x6's not 2x4's, more comfortable for the feet. Leave 1.5 inch gaps between. And I would cut them to length, paint them on all sides, assemble, and paint again.

Most of Ghosthawk's advice is real horse's mouth stuff, but I'd leave smaller gaps between the boards. It's more comfortable on bare feet, a lot more things fall through 1½in. gaps than ½in. (and in the life of a dock it will be a key someday), and the latter would be just as good for ventilation to reduce rot.

I don't know about sawdust and plastic, but if you use wood tar and fine gravel, not too sharp, it is about the best non-slip surface you can get. I used to walk on a pedestrians-only pier treated that way, perhaps before the First World War, and it didn't change in decades. With a small closed pond with fish, you should do that some way from the water. The same goes for real creosote if you have protected from it, which is far superior to the modern rotproofing compounds.

You would probably find more uses for it when you've got it. Kids would love to detach it and use it as a raft, and on an acre if they can swim forty yards, they're never all at sea.

Purpose-made plastic floats should outlast wood. So they are worth setting up a followed search for,. with e-mail notifications, on eBay. If someone has a few of those going spare, he has to reconcile himself to letting them go cheap.

[country gent]

I would also consider putting the center row of barrels slightly lower than the outer rows. 2"-3" should be enough. This way the center supports more of the weight and the outers provide more stability to the dock. Also rubber pad the barrels were bands are used to attach to the dock or the bands will cut thru the barrels from motion over time. Securing it to the bank of the pond may or may not be needed. A way to maintain load with water level raising and dropping over the summer is an advantage also.

[Ballistics in Scotland]

Or just make the frame grip the barrels tightly, with all the wood above water if possible. They aren't going to dive to get out of the frame.

[shooterg]

If you're near any big lakes where used boats show up, at times you can pick up old pontoon boats for not much. Just fit boards on top of the pontoon base , or use as is ! . We had one on a 7 ac. park pond as a maintenance platform but could use it for a portable dock.