View Full Version : suggestions for lifting boat dock

04-17-2003, 07:28 PM
Sometimes I need to adjust the height of my boat dock when the water rises and falls throughout the seasons of the year. It is redwood 2" x 8" for stringers and 2 x 6 for decking and supported by 1.5 inch galvanized pipe. There are brackets made of the next larger size pipe that are carriage-bolted to the side of the stringers and a big set screw that tightens against the inner pipe. When I loosen the set screws, it is really heavy to hold the dock until I get it adjusted and tighten them again. Most of the year, the water is too cold and deep to get into to lift from below. The support pipes are of varying heights but all stick out above the dock.

What I am considering is using a lever about 3 or 4 feet long with a fulcrum that slides into the pipe and attaches to the dock with a chain and hook under the stringer. Then I could get my wife to hold the lever while I loosen and tighten the set screws.

The problem with this idea is that it takes two people-- one must hold and adjust the lever and one must tighten the screws. Another idea might be to use a small hydralic jack in some kind of a sliding yoke and then it would hold its weight intil the set screws are adjusted. Besides that, it is pretty hard to get my wife to help in any of my projects since I told her the story of a guy I knew who made his wife hold a sheet of plywood in the back of his pickup on the way home from the lumber yard. Somewhere along the way they met a big truck and wife and the plywood blew out to their demise. Now my wife asks before helping if this is anything like holding plywood.(that and the several times that she has had to haul me to the hospital for stitches. Several long and embarassing stories too stupid to recount here among my friends)

Anybody have any good ideas? My dock is almost under water at the moment so I think we should disqualify any idea that involves left-handed acme screws, computers or anything else too involved. Thanks--Mike.

Dave Opincarne
04-17-2003, 07:44 PM
Mike, If your up for the task, modify the dock to ride with the water level by using poly barels for flotation and riding up and down a pipe atached to the pilings via a hoop atached to the dock. Simple rollers could be cut out of nylon and strung around the hoop to prevent binding. Other than maintaining wear and tear their would be less hasel than constantly adjusting the level of your dock.


04-17-2003, 08:03 PM
I adgree with Dave.. Seen it done a hundred times on the tennessee river. Last time Joe did it he took the plastic barrels and had expanding foam injected into them. He went to a local plant and used thier machines they use to make packing for instruments, filled them up and gave them a hundred dollar bill.. I figure this was for about 2 dollars in foam.. He said it would have took him a hundred cans of great stuff foam tho. strapped them 0n with bands and 1/4 inch nuts.
Joes dock can do double duty when he has his pontoon boat out. he can tow it. He has jet ski's a big ski boat and the party boat is always the pontoon boat.

04-17-2003, 09:28 PM
How about hooking a "come along" in the top of the pipe, and under the stringer, then you can support on the come along as you loosen/lift/lower the dock. Don't know how much pipe sticks out the top, but this would work if the pipes are long enough.

mike thomas
04-17-2003, 10:48 PM
I have seen a boat winch with a box on the bottom used in this fashion. The box goes over the end of pipe. This is pretty much the same idea as using a come along, but can be used over shorter lengths. Mike

04-17-2003, 10:51 PM
I was trying to visualize your set up. If I have it right in my minds eye then the 1 1/2" pipes are the posts and the brackets support the weight of the dock by the set screws binding on the posts. This may have worked but it isn't ideal. If you ever invite Thrud and Alistair to your dock, you're going to find some grooves where the set screws were.
How about this idea. Get some pieces of chain and affix one end to the bracket, either by welding or bolting. With a cutting torch cut a slot at the top of the post tubes. The chain slides into the slot and supports the bracket. The excess chain hangs inside the post tubes. This way you don't depend on the set screws to support the weight. As for lifting, I think I would use a come-along instead of the wife. Also you might find some end caps that would fit over the post ends to prevent snags or accidents. It would help to know how wide and long the dock is and how many posts it is supported by. Good Boating

04-17-2003, 11:37 PM
Thanks for all the ideas so far. The dock is about 25' long and 32" wide with a dog leg in the middle. It is supported by three pairs of pipe legs.
The barrels would be too unstable for such a narrow width, I think. I like the come-along idea-- I would have to make some extensions for the posts that would fit inside the existing pipes to attach the come-along. The winch idea is good too--I have an old one that needs a little TLC. If Alistair and Thrud come over, I'll have reinforce the dock and hide Grandma's cinnimon rolls.

04-18-2003, 08:16 AM
My old boss had a boat we made out of 12inch thingauge I beam and floated on corragated plastic cylinders three feet in dia. strapped to bottom. It road high in water. His place at lake was on a point and dock got hammered by every storm. It had to be repaired everyear until we welded boat trailer winches to pilings and raised dock clear of water. never needed floats again. His dock had square holes with pilings driven through. pilings slid on plastic sheets bolted to squares. around corner from his place it was calm and you could float a dock on dixie cups.

04-18-2003, 10:53 AM
I didn't like the setscrew idea either, my dock has SS bolts though the 1 1/2 tubing to support the dock.

I use a come-a-long to adjust the height above the water. Now if I could figure a good way to put it in and take it out of the water every year I would be set.


04-18-2003, 02:48 PM
Mikem,We just launched our float system for the season which is quite extensive. Due to ice and rough weather in the fall, our foam billets become "eaten". To trim the floats we have many plastic 55 gallon drums we fill with water stuffed under the floats and when launched,air is pumped into each one as needed for trim. We bring the little air pump down and plug it in, 25 munutes later the float is trimmed. A little work on land and you can adjust the float anytime with with a small electric air pump. Dave

04-19-2003, 09:22 AM

I too take breaks spending money on the shop in order to spend money on a boat. Anyway, I have a similar set up. Being an engineer, I of course have to have my dock level so I came up with a unit that allows fine ajustment. Part one is a "can" that slips over the dock pipe, although I'm considering a post that would go inside the dock pipe and has a shoulder to support it (you wouldn't need to leave the pipes as long). part 2 is a crank handle and 3/4 all thread that screws into a tapped hole in the top of the "can". Part 3 is a miniture set of forklift forks hanging from a crossbar that rides on a shoulder turned in the all thread. So, you drop one assembly onto each side of the section you're leveling, hook the forks under the stringer, loosen the setscrews and crank away. I should note that I am able to do this from the water, I don't stand on the dock that I'm adjusting. I think you would need to add thrust bearings if your water is too deep for that. Just a different way - slower than a comealong. Good luck.


04-19-2003, 11:33 AM
I've had the same problem on my small dock and have used Pony crank type woodworking pipe clamps. One end under a stringer and the other end on the top of my 4x4 PT posts. The 4x4 posts are attached by heavy cast aluminum clamps and this makes the job pretty easy. The range of the pipe clamps may not be adequate for your needs, however. They would need to be re-adjusted every 5 to 6 inches or so.

04-20-2003, 01:49 AM
I have seen piers with a boat trailer type winch mounted on the pier with the cable run up and over a pulley mounted in the top of your support posts then back down to the pier. With this set up you just crank the pier up or down with the winch and then use some type of clamp on the pipe to secure it.

04-20-2003, 07:18 PM
Mike: if the come along idea sounds good, try putting a pipe inside the existing pipe (or out side with a cross pin to keep it from sliding too far. Then rig your comealong on the top of the "gin pole" you just made with the extention pipe. Would give you plenty of rigging room, be light and easy to store.

04-20-2003, 11:45 PM
Thanks for the replies. I like the come along idea. Functional and simple. I don't know why I didn't think of it myself. (this is what friends are for--to keep me from doing something rash, before thinking it thru) I think like docsteve says, that I will find the size of pipe that will slide into the pipe legs and use a reducing pipe coupler as a stop so that the smaller pipe doesn't slide into the leg too far and put a piece of larger pipe into the reducer and hook the comealong onto that. This is the easiest fix. That doen't mean that I won't use my welder and mill later to create the "Mona Lisa" dock winch. Thanks, Mike.

04-24-2003, 01:35 AM
If you hang your brackets from chain and have a slot in the top of the post like I described then you could use the lever idea to lift the bracket. You would have to drill some holes in the post tubes. The lever would go through the chain and into the hole in the post. Then after lifting, a new link is dropped into the slot and the excess goes down inside the post tube. No more set screws.

04-24-2003, 01:51 PM
Spencer has best idea yet, I think. put a collar around the post (before installing the chain), make a forked lever with a chain hook (or slot). Then jck it up a link or more at a time- piece of cake!!!

Was gonna suggest a "walking chain binder", but thats one of those common tools that don't seem to be around any more.

Edit comment- if you try the gin pole/coupling idea, keep in mind that you should weld- not thread- the reducer. Pipe is very weak at the threaded joints. been there (blushing). If you try the threaded joint wear a bathing suit and pick warm weather/water.

[This message has been edited by docsteve66 (edited 04-24-2003).]

04-24-2003, 03:07 PM
Once I visualize a problem I sometimes can't get it out of my head for a while. The problem with levering up the bracket is that you would be trying to lift up on the lever. This would work fine if you are in the water and standing on the ground but ideally you want to be on the dock. So now you need a special lever where the fulcrum is on the pipe but the lever is on the other side so that you can lever down as the bracket and chain lifts up. This way all of the force you apply is working for you and reducing the load of your weight on the bracket. Good luck.