Floating Dock on Recycled #tidycats and #2liters




About: "Experience is what you get, when you don't get what you want." -Randy Pausch

I set out to build a floating dock for a local music festival on the bayou. Bayou Boogaloo is my favorite festival in New Orleans, primarily because of its vicinity to and the capable use of Bayou St. John to enjoy this growing free festival. For years we have tied up my pirouge and various other canoes and blowup boats to create a virtual floatilla of barges in the bayou while enjoying the 3 separate stages of music; moving up and down the bayou to enjoy each performance. I decided last year, because of its growing popularity and the limited seating capacity within my boats, to create a floating dock in order to host more friends on the bayou.

Step 1: Collecting Materials to Repurpose

I already save my tidycat boxes, re-purposing these in a multitude of ways. These 5 gallon buckets are perfect storage bins. Very durable with solid form. Additionally I began collecting 2 liter bottles and 1 gallon cranberry juice bottles etc. At that point I had no real design, I just knew I need to acquire materials that could provide buoyancy, with only a year to do so. My final design only used the tidy cat boxes and 2 liter bottles, however next year, I plan to expand using milk crates and cranberry juice gallon bottles.

I knew I wanted to utilize as much recycled materials as possible in the build-out. This was very much a custom piece, as other than paracord all materials had previously been acquired and sorted as scrap materials for my many various projects that keep me occupied throughout the year.

Step 2: In the Beginning: Calculations

My parents built my childhood home, in the early eighties, shortly after I had came along, and my father had built these shutters for our windows no long thereafter. These two 30+ yr old shutters were what would become the principal recycled markers of my design.

I attempted to research plastic bottle boats, recycled material boats etc. in order to gain inspiration and insight. I reviewed other Instructables among other random Google image searches etc.

I knew I would have to make use of Archimedes' Principle:
'Archimedes' principle indicates that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces. Archimedes' principle is a law of physics fundamental to fluid mechanics.' - Archimedes' principle, Wikipedia, n.p. Web. 23 April. 2014.

I also referenced calculator-converter.com to convert volume units into lbs of pressure.

1 liter = 1 kg = 2.204622622 lbs; 1 gallon = 3.78541 liters = 8.34540 lbs

2 liters = 2 kg = 4.409245244 lbs : 5 gallons = 18.92705 liters = 41.7270 lbs

I then began by first tying six boxes to each shutter, although this would eventually change as my design evolved; it made it easier to move the objects around as I contemplated between a catamaran and simple dock design. I eventually settled on a dock design. I contemplated a number of decking options, realizing my original preference would take away more bouyancy than I wanted to give up.

Step 3: Testing:

At first, I tested my dock with only 20 boxes and lite decking. It measured approximately 7 ft x 6 ft topside. Each box had its own cubby it wedged into or partnered with another under the decking, primarially by 2x4's. I then created a labyrinth style netting configuration attached to the underbelly of the deck.

I wanted to test it out, make sure it didn't sink and wasn't a waste of time. The bottles and front and back extensions (pictured here) were not complete nor used on its maiden voyage. It definately wasn't a waste of time, but it did wobble...a lot.

My wife and I had to be sure we stayed on our own sides to keep the deck balanced.

This was exactly the trial/error data I needed to determine what next.

Step 4: Wings!

I continued by replacing the front and back anchor boards with longer pieces to create additional surface area for the addition of wings to square up the deck. The wings added were 4 additional boxes and 70 two liter bottles.

Each set of two liter bottles (35 per side) forced an additional extension to accomidate each box on each corner bumping them out just enough to add to the structure, causing the stability to be increased exponentially.

All that was left was to sand, paint, and transport to launch in the bayou.

Step 5: Final Test and Launch:

I wrapped up the night before, with only a few finishing touches to complete on the day of launch.

To transport we flipped the dock on its side, checking the mesh netting I created was still tight holding each box in place. The only exception were the four corners and the bottle torpedos; they each were removable to allow for ease of transport and launching.

It was a great success! We floated it for the entire three day festival.

Already planning an addition for next year: lessons learned and experence going to go a long way!

Additional Measurements, Calculations & Notes:

1310+ lbs = lbs of pressure to sink this dock.

24 tidycat boxes = 120 gallons = 1001.448 lbs

70 two liters = 308.647 lbs

As a general rule it's best to reserve a minimum of 25% as a safety net for buoyancy.

1310 * 75% = 982.5 lbs remain for materials and cargo, i.e. decking, passengers, etc.

After a generous estimate: decking/materials @ 150 lbs and 4 passengers @ 200 lbs each.

982.5 - 950 leaves a remainder of 32.5 + the 327.5 lb reserve for a total of 360 lbs for safety.

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39 Discussions


2 years ago

Absofrigginglutely love repurposed materials!! Especially the water bottles going to a great use!


4 years ago on Step 5

Thank you, very easy to grasp, good pictures, will try out some of your ideas next week in Gdansk - making the first steps of an Eco Island Lab. Will send you pictures.. or check out on FB: Eco Island Lab Gdansk. Cheers, Oleg

Thanks! Next weekend is festival time again. Having completely demolished my maiden version, I have to get busy and rebuild a new one immediately!

Thanks. Still waiting on all the items from my prize pack, but the overall experience of sharing my Instructables is still a positive one.

Perhaps. I learned alot putting it together; the most difficult part was transporting it to and from the water, but I have fix for that next year. Can't wait until then. - Thanks!


5 years ago on Introduction

It looks awesome, but will it weather a storm of any kind? Seriously, I am interested, let me know.

1 reply


I didnt build it with those specifications in mind, but I have no doubt you could make it so.

Why Not... should always follow What If!


5 years ago on Introduction

Excellent water craft. For years I have wanted one of the store-bought floats for our pond. You have inspired me to a different kind of float. Great work.

1 reply

5 years ago on Step 5

I like this!With the extra bouyancy,I got to thinking,you could put a trap door over say,2 of the Tidy Cat boxes on opposite sides,and fill with ice and drinks for the trip!

1 reply

Thats what the center trap was originally going to be, space for an Ice chest that we could take to and from daily but I was worried it would float too high.



5 years ago on Introduction

Your friends are so lucky to have such a beautiful raft from which to enjoy the music festival. You must have been the envy of a lot of other festival fans.

I especially liked using the shutters from the house your dad built, knowledge and use of the Archimedes' Principle, and the foot-well in the middle of the raft. You got my vote!

1 reply