USAMARINE Web Group - Captains' Corner Boatbuilding Tips

Mounting Chair Plates onto Deck:

Chair mounting on cockpit deck

There are numerous ways to mount a pedestal on your cockpit deck, but this is the method I prefer.

First you need a backing plate for any heavy hardware item that's mounted to a surface.  A fighting chair will need an oversized thick plate to withstand the potential torture that it can apply to even the strongest deck.

The backing plate will be made from 1/2" thick marine grade aluminum.  This thickness is necessary so that the bolt holes can be threaded, thereby excluding the necessity of washers and lock nuts.

Remember that aluminum and stainless steel will lock together permanently in a very brief time, so when you're ready to make the final installation use a very high grade anti-seize compound on the screws.  There is no finer anti-seize compound than TefGel

TefGel TefGel

Once you've decided on the un-drilled plate dimensions and placement under the deck, rough up one surface of the plate with a high speed grinder fitted with a 24 or 36 grit disk.  Apply a liberal amount of Fast Set 3M 5200 and wedge the plate into place under the deck.   Don't wedge it too tightly, you want about a 1/8" bond layer.

After the adhesive sets, (about 24 hours), mark the position of the pedestal plate and the bolt holes.  Pre-drill the holes all the way through the deck but not the backing plate with a 3/16"e; bit.  Enlarge the holes in the deck to at least 1/4" larger than the mounting screws and fill them with thickened epoxy (see Hardware Mounting in Composites).  When the epoxy has cured, re-drill the holes, this time all the way through the backing plate.  The size of the bit needs to be the correct size for tapping the holes to match the mounting screws.

Check your installation for final fit, run a small bead of sealant around the down face of the pedestal plate, apply the TelGel to the bolts and screw down the plate & you're done.  No need for wrenches or someone else to help with the through bolts.

Have fun! Feel free to download and print this article, but please don't use it on a website without linking it to

Capt Patrick McCrary

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834 Scott Dr., LLANO, TX  78643
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