Where to find info on building a pier/boat dock

[slydog]

Does anyone know where I can find info on building a pier or boat dock? I did a search of the site for pier and dock and came up empty handed. I'm mainly concerned with what kind of posts to use for the main supports, and how to go about setting them into the soft bottom. ie, do I need to bury them like in a post hole. How do I make sure they are compresed and will not settle further into the mud etc etc. Any help or direction will be greatly appreciated.

 

[ford15005]

Hey, this is a topic I too would be interested with what responses you receive. I've been kicking around "floating foam" like used on the lakes (understand expensive), sealed plastic drums, sinking forms & pumping out before concrete fill,...

 

[keeney]

For a semi-permanent installation, I have seen that the posts are typically driven just like a fence post. Pound on the post with a post pounder it until its deep enough for side-stability and firm enough to not sink any further.

Typically 1-1/2" or 2" galvonized steel pipe is used.

The pipe is positioned and slid down through special clamping brackets that are bolted to the side of a wood frame and deck. If the deck is already constructed it is easy to position the pipes by floating the wood deck in the water in the desired location and driving the pipes through the clamps. Then you lift the deck up with a come-along hooked to the top of the pipe and then tighten the clamp to hold it there.

The deck is typically built in 8 to 12' long sections. The tradeoff being how heavy and expensive each deck section is vs. how many posts need to be purchased and driven.

For neatness sake, you can trim all the posts to the same height after they are driven in and apply a plastic cap.

If a post does settle a bit, you can re-level the deck by repositioning the clamps on the pipe. Also, if the water level changes, you can ajdust the height of the deck to accomodate the desired height off the water.

Seasonal removal of the posts is the reverse process with a post-pulling slide-hammer being used to pound up on a hard pin slid through a hole drilled through the upper portion of the pipe.

Floating docks of any length would typically still require some posts to be driven to keep the dock from blowing around. These post would fit through hoops or larger pipes with an inch or so of clearance to allow the dock to float up and down, but not move too far laterally. Floating is good for large seasonal or tidal variations in water height.

Other types of dock assemblies used here in MN would be free-standing steel or aluminum structures, perhaps with some wheels on the legs to facilitate easy seasonal installation and removal. A small tractor comes in handy to install and remove these.

As far as bulding forms for concrete and pumping out the water, I am not sure you need to pump out the water. Build the forms in the water. When you pour in the concrete, it will sink to the bottom and the water will float out over the top of the form. Mix the concrete fairly stiff as some dillution will occur, but it will mostly stay together. The top surface above the water will not be dilluted and you should be able to finish/seal it nicely without losing all the cream.

 

[RedRocker]

Many years ago I was involved in building a small dock at my FIL's place on the gulf coast. He had a guy "Jet" the treated posts in the sediment. He took a gas powered water pump with a long pipe on the end of the hose, stood it beside the post and cranked it up. The water jet blows a hole in the bottom allowing the post to drop down. Pull out the pipe and the post was set like concrete. That's how I remember it anyway.

 

[PILOON]

How I build docks:

I basically make up a large 'pallet' using treated 2 x 8 stock for the framework and deck it out with 1 1/4" X 6" deck planking.
When I say pallet I also use deck planking on the underside (usually 3 planks to make a 20" bearing surface).
I then use 10" X 20" X 96" foam floatation blocks.

Like a deck I leave 5/16 gaps for drainage.

Made many 12' X 16' docks this way using 3 sets of foam floats, one at each end (12') and one in center.

With a helper and a pneumatic nailer it is a one day job.

This way the wood structure never is in the water, hence does not rot and being set up as a giant pallet the unit is structurely very sound.

Around here we never remouve from the lake and generally get up to 5 ft of snow accumulation.

I just changed one that lasted 30+ years.

To keep the foam billets from sliding out of place I make sharpened wooden stakes (about 2" x 2") that I drive into the foam (near the center) and fasten to one of the joists.
2 stakes per foam section does the trick.

I have tried everything from barrels to cribs and poles and the foam is the easiest fastest and most durable route to go.

Sure, a 12 x 16 dock will cost about $1000 (Canadian) but figure a 25 year life without maintainance.

For a smaller docks 2 x 6 joists are OK up to say 8" x8" dock.
Have made 8 x 8 dock with but 2 6" thick foam blocks and it worked OK except that with 2 folks on one corner you get wet feet.

Barrels make for a very high dock that is easily tipped to a wild angle as only a small portuion of the bbl makes contact with water and when loaded up it sinks to the point of bouyency.
Steel bbls last about 2 yrs max due to condensation and plastic drums float even higher.

Good luck!

 

[PILOON]

I should add that a very attractive feature is that you never have high/low water problems as the dock simply rides on the water's surface.

The 'pallet dock' as I call it, rides a comfortable 12" or so from the water's surface making for easy boat/canoe entry.

 

[kensfarm]

We use to park our boat at a buddy's house that does pier work for a living.. he even has the diving outfit that lets him work in the winter.. and chainsaw under water when removing old piers.

I know he pounds the pier posts in.. but another method was using pressurized water to sink the post in too.

 

[TheKid]

Don't know about about the pier kind. Around here the docks all float because they lower the lake about 5' in the winter.

 

[slydog]

Thanks for all the info! How stable are your floating docks if you have say, 3 or 4 people trying to fish off of them?

I was kind of thinking about driving some 6" schedule 40 pipe into the mud. Maybe blowing out the inside muck with a water hose and nozzle. Then driving a couple of pieces of 1/2" rebar into the mud inside the pipe, then filling this all with cement. Does that sound like it would work ok? I could run some dowels through the pipe at the top for knockouts to bolt through for the runners. Does that sound like overkill?

 

[iris49truck]

The type of construction really depends on the type of water bottom you have. Here in east Texas we have a sand and clay bottom so you have to drive the posts into the mud far enough that they can support the weight. I will attach a series of pictures that show how they used a trackhoe to push and pound pressure treated telephone poles into the bottom anywhere from 6 to 8 feet deep. They basically kept pounding on them until they wouldn't go any farther. The first is the picture of them swinging one of the long poles into position.

Terry