Pond Boss
Posted By: woodwalleye Floating dock stability?? - 04/25/13 07:14 PM
I'm going to build a floating dock using barrels. I have 6 x 55 gallon plastic barrels that I can disperse equally around the platform edge. I have a small (1/3 acre) 10' deep protected pond - no big waves, wind, etc... Just want something to sit/lay/fish on, something the kids can use to swim from.

I know 8x10 or 10x10 would be more stable that 8x8, but I'm thinking the 8x8 size would fit my needs just fine and would be a little bit cheaper... Will I have any stability issues with a floating 8x8 dock? I'm thinking I should have plenty of flotation with 6 barrels, and could add water to each barrel to ballast and stabilize the whole system.

Thoughts on 8x8 floating platforms? Do I need to go any bigger than that? Opinions?

Thanks! smile
Posted By: liquidsquid Re: Floating dock stability?? - 04/25/13 07:27 PM
4 barrels will be enough, then fill approximately 1/3 the way with water. The dock will sit low, but stable. 6 Barrels will be too high with an 8x8 dock and very wobbly. Mine is a 10x10 floater with 4 barrels and it sits a bit too high until you get 6 adults on it.
Posted By: esshup Re: Floating dock stability?? - 04/25/13 07:45 PM
Originally Posted By: liquidsquid
4 barrels will be enough, then fill approximately 1/3 the way with water. The dock will sit low, but stable. 6 Barrels will be too high with an 8x8 dock and very wobbly. Mine is a 10x10 floater with 4 barrels and it sits a bit too high until you get 6 adults on it.


Depends on the weight of the dock and how it's designed. Each barrel will float roughly 450# of weight. At that point it's fully submerged (theoretically).

If the barrels will be inside the joists, then each barrel will float 225# until the wood joists touch or barely touch the water. Barrels are roughly 22" in diameter.

Calculate the weight of the wood that the platform will be made from and how many people you expect to be on it at one time.
Posted By: Omaha Re: Floating dock stability?? - 04/25/13 07:52 PM
I'm about to build one as well so this is a timely thread woodwalleye!
Posted By: Zep Re: Floating dock stability?? - 04/25/13 08:11 PM
You may find these links helpful:

(only first 20 seconds is loud)
http://www.youtube.com/watch?v=NY7IptqooSQ


http://www.youtube.com/watch?v=aR7qPC90gto
Posted By: esshup Re: Floating dock stability?? - 04/25/13 08:43 PM
FWIW, I'm building a floating pier, the floating part is a "T". Bottom of "T" is 4'x16'. Top of "T" is 8'x12'. Joists in the bottom of the "T" are 2x10's, top part of the "T" has 2x10's on the outside, 2x8's on the inside. Decking is 5/4x6". I calculated that with 22 55g barrels, the joists will be just above the water with the barrels empty.
Posted By: catmandoo Re: Floating dock stability?? - 04/25/13 09:01 PM
"Stability" is in the minds of those on the dock.

My floating platform is 12'x12', with a 4'x12' "brow" (gang plank). It has fifteen 55-gallon "blue barrels" holding it up. The frame and joists are 2x12s and the decking boards are 2x6s. The 4-foot wide walkway is decked with 2x6s over a pair 2x10s attached to hinged 4" concrete bollards sunk 4' feet into the ground.

I consider it quite stable. But, some friends drove up the other day as I was getting ready to fill the feeder on this dock. One of them walked onto the platform just as I was hoisting the feed bag. The dock was moving. He very seriously panicked. I thought he'd be "seasick" before he got 15 feet back to terra-firma. This isn't the first time I've observed this.

Maybe I'm just hardened after growing up on the water, spending six years in the Navy, spending lots of time in small planes ...

Anyway, as our good friend Bill Cody always says -- "it all depends ..."
Posted By: liquidsquid Re: Floating dock stability?? - 04/26/13 01:35 PM
I have some relatives with inner-ear issues, they won't get near anything that shifts like a floating dock or they would stumble and fall right in. That was one of my concerns about my dock, and why I decided to make it fixed (and the floater is for out in the middle). I didn't want visitors to come over and fall in from an unstable dock.
Posted By: woodwalleye Re: Floating dock stability?? - 04/26/13 01:38 PM
Made up my mind last night to go 8x10. Picked up the frame material at Menards last night. Shouldn't take long to put it together, and my 8 year old says he'll help out. smile I figure I'll go with 6 barrels and add ballast as needed.

Any other tips, tricks or insights are still (always) welcome!


Thanks!

Mike
Posted By: JKB Re: Floating dock stability?? - 04/26/13 06:53 PM
Originally Posted By: esshup
FWIW, I'm building a floating pier, the floating part is a "T". Bottom of "T" is 4'x16'. Top of "T" is 8'x12'. Joists in the bottom of the "T" are 2x10's, top part of the "T" has 2x10's on the outside, 2x8's on the inside. Decking is 5/4x6". I calculated that with 22 55g barrels, the joists will be just above the water with the barrels empty.


Have any CAD files to share?

In AutoCad, you can just click export, then choose .bmp, then select objects, and voila! Using photobucket, you have to convert to .jpg now otherwise the upload will fail. Stooooopid Photobucket!
Posted By: Cecil Baird1 Re: Floating dock stability?? - 04/26/13 09:13 PM
Originally Posted By: catmandoo
"Stability" is in the minds of those on the dock.

My floating platform is 12'x12', with a 4'x12' "brow" (gang plank). It has fifteen 55-gallon "blue barrels" holding it up. The frame and joists are 2x12s and the decking boards are 2x6s. The 4-foot wide walkway is decked with 2x6s over a pair 2x10s attached to hinged 4" concrete bollards sunk 4' feet into the ground.

I consider it quite stable. But, some friends drove up the other day as I was getting ready to fill the feeder on this dock. One of them walked onto the platform just as I was hoisting the feed bag. The dock was moving. He very seriously panicked. I thought he'd be "seasick" before he got 15 feet back to terra-firma. This isn't the first time I've observed this.

Maybe I'm just hardened after growing up on the water, spending six years in the Navy, spending lots of time in small planes ...

Anyway, as our good friend Bill Cody always says -- "it all depends ..."



Mine's fixed but it wobbles if you're not used to it. My last dog spread her legs out really wide as she walked on it the first time she got on. It was funny to watch. Funny thing is I don't notice myself doing anything different but it no longer wobbles for me. But for a newbie it does.
Posted By: JKB Re: Floating dock stability?? - 04/26/13 09:46 PM
Originally Posted By: Cecil Baird1
Originally Posted By: catmandoo
"Stability" is in the minds of those on the dock.

My floating platform is 12'x12', with a 4'x12' "brow" (gang plank). It has fifteen 55-gallon "blue barrels" holding it up. The frame and joists are 2x12s and the decking boards are 2x6s. The 4-foot wide walkway is decked with 2x6s over a pair 2x10s attached to hinged 4" concrete bollards sunk 4' feet into the ground.

I consider it quite stable. But, some friends drove up the other day as I was getting ready to fill the feeder on this dock. One of them walked onto the platform just as I was hoisting the feed bag. The dock was moving. He very seriously panicked. I thought he'd be "seasick" before he got 15 feet back to terra-firma. This isn't the first time I've observed this.

Maybe I'm just hardened after growing up on the water, spending six years in the Navy, spending lots of time in small planes ...

Anyway, as our good friend Bill Cody always says -- "it all depends ..."



Mine's fixed but it wobbles if you're not used to it.


HuH?

Turbine engines have components that are supposed to be fixed. Yet, some times they wobble. When this happens, the wobbling effect causes great fatigue, and things just go crazy after that.
Posted By: Cecil Baird1 Re: Floating dock stability?? - 04/27/13 12:26 AM
Ah but bridges and building are designed to sway a little aren't they? Especially in earthquake zones?
Posted By: Omaha Re: Floating dock stability?? - 04/27/13 02:03 AM
A good friend of mine worked on this one earlier today. Larger lake with significant water fluctuations.

Posted By: Omaha Re: Floating dock stability?? - 04/27/13 02:08 AM
Looking at that picture, how effective are those pvc "posts" going into the water, connected to the dock, I assume pounded into the pond bottom?
Posted By: Cecil Baird1 Re: Floating dock stability?? - 04/27/13 03:23 AM
Originally Posted By: Omaha
A good friend of mine worked on this one earlier today. Larger lake with significant water fluctuations.



Wow that has some steep banks!
Posted By: Omaha Re: Floating dock stability?? - 04/27/13 01:37 PM
Yeah it does. Not very angler friendly without the dock.
Posted By: Cecil Baird1 Re: Floating dock stability?? - 04/27/13 01:44 PM
Originally Posted By: Omaha
Yeah it does. Not very angler friendly without the dock.


Erosion issues or caving in of the banks?
Posted By: Omaha Re: Floating dock stability?? - 04/27/13 01:48 PM
Not sure. Didn't see the place myself. We're going to be building one ourselves, so I asked him to take some pics. I can ask him later today.
Posted By: esshup Re: Floating dock stability?? - 04/27/13 02:37 PM
How far does the floating portion sway side to side with the plastic pipes holding it in place? Or are those plastic pipes acting as sleeves over smaller dia metal pipes?
Posted By: Omaha Re: Floating dock stability?? - 04/27/13 03:24 PM
No idea. I will ask.
Posted By: DonoBBD Re: Floating dock stability?? - 04/29/13 10:56 AM
This is what I plan on building for my dock to stabilizing the 16X16 dock with a 5X12 gang way to the dock.

I have to do some more math on it but I really think it will anchor the dock from the wind and keep any quick bounce and jounce out of the dock.

Cheers Don.

Attached picture dock stabilizer.jpg
Posted By: esshup Re: Floating dock stability?? - 04/29/13 11:27 AM
That looks like it would do it. We did something similar with a ski jump that we had in a lake.
Posted By: roadwarriorsvt Re: Floating dock stability?? - 04/30/13 07:29 AM
Don't over-engineer it (did I really just say that?) Floating docks aren't all that unstable, especially if constructed correctly. Using more barrels and partially filling them with water or even just hanging ballast from each corner of the dock will do wonders for stability.
Posted By: gallop Re: Floating dock stability?? - 04/30/13 11:07 AM
Dono

I have seen a dock c ballast at the corners in the form of fish attractors made from concrete weighted buckets with PVC ran through themattached to underside of dock with chain

The fish attractor size makes it better for deeper water though
Posted By: Dwight Re: Floating dock stability?? - 04/30/13 12:17 PM
True dock floats that are foam filled and flat on the bottom are the most stable flotation. Even when our "Barge" is free floating you can jump up and down on a corner and it barely moves. Of course, the floats are more expensive than air filled barrels.

When I build something I design it to last a lifetime. but that is just me.
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