Here's what matters: Dock floats ship with a small open vent hole so they can breathe during shipping and storage. That hole needs to be sealed with the included vent plug once the float is in the water and ideally before you install decking. Seal it too early and the float can swell from heat and pressure. Seal it at the right time and you keep water out for the long haul.
Why Dock Floats Have a Vent Hole
Eagle Floats arrive with one small hole left open on top. That opening is intentional.
During transport and while the float sits out of the water, temperature swings cause air inside the shell to expand and contract. Without a way for that air to escape, pressure can build and the float can swell, distort, or even crack. The open vent lets the float “breathe.”
Once the float is in the water, the water temperature regulates the internal pressure. That’s when you close the vent with the provided plug so water can’t get in.
You’ll find the plugs in a small bag, usually tucked under one of the mounting locations or included with your hardware. A spare is included in case you lose one.
When to Install the Vent Plug
Timing is the most important part of this job.
Wait until the float is in the water or install right before deploying.
The assembly guide puts it plainly: if possible, install the vent plugs just before (or right after) you put the dock in the water. Water acts as a thermal regulator. Floats sealed too early are at risk of swelling.
Best sequence:
- Attach the dock float to the structure.
- Get the dock float in the water.
- Install the vent plugs while you still have access to the tops of the floats.
- Then install decking (if you haven’t already).
If you deck the dock on land and launch it fully decked, you’ll need a way to reach the float tops afterward. Alternatively, install the plugs immediately before launch, once the floats are no longer sitting in direct sun.
One thing to note is that direct sun light can accelerate this internal pressure build up drastically. A float in direct sunlight with a plug installed will often swell within 10-15 minutes.
How to Install the Vent Plug
This is a quick job. Here’s the practical way to do it.
Step 1: Locate the Open Hole and Plug Bag
On the top of each float you’ll see a molded circular area with a small open hole in the center. It may still have a bit of white foam or protective material visible inside. That’s the vent. Clean any debris or loose material out of the hole so the plug can seat cleanly.
Attached to the float with adhesive is a bag containing the vent plugs. Sometimes this bag is tucked in the attachment points so please look carefully.
Step 2: Prep the Plug (Optional)
The plugs are black, threaded, hex-socket fasteners. A spare is included with each float’s bag. Apply a small amount of silicone or marine-grade thread sealant to the threads. This isn’t always required, but it helps create a reliable seal and is what our assembly guide recommends.
Step 3: Thread It In
Start the plug by hand to avoid cross-threading. Then use an 3/8" Allen key (hex wrench) to snug it down. Don’t overtighten, just make it firm so the threads seal. Repeat this for every float. One thing to note is that the plugs are plastic and are prone to shrinkage and expansion. This may cause the 3/8" Allen key to feel a little loose or tight.
Common Mistakes to Avoid
- Sealing the vents too early. The number-one issue. Leave them open until the floats are in the water (or immediately before launch).
- Forgetting them entirely. An open vent lets water in over time. Check every float before you finish the decking.
- Losing the plugs. That’s why a spare comes with each bag.
- Installing after the decking is down. Once boards are on, reaching the float tops is much harder. Do the plugs while you still have access.
Missing Plugs?
Were your plugs lost in transit? Lose your plugs in the installation? Not a problem! Contact us and we’ll help you sort it out. Even if you didn't order the floats from The Dock Shop we will do what we can to help.
Need the Full Build Walkthrough?
Vent plugs are one small step in the overall process. Check out the complete Floating Dock Kit Assembly Guide for more information beyond plug installation.
Questions about timing, sealant, or anything else on your build? Contact us and we’ll help you sort it out.
