I want to mount a grab bar very securely in the deck of my J16 Carolina Skiff, while making sure I seal the fasteners against water intrusion. From what I’ve read, drilling an over-size hole through only the top layer of the deck, then bedding with filled epoxy and either setting a waxed bolt in the green epoxy to form threads or tapping the cured epoxy to the right size later, is the way to go. In either case, neat epoxy is applied to the clean bolt as it is screwed into the hole when mounting the grab bar. I’d like to hear from someone who has actually done this, or if there is a better method, I’d like to hear about that, too. Thanks for any help–I really want to this right and do it only once!
I’ve done this numerous times. Good on you for doing it right, too many boats are ruined by doing it wrong.
Drill the hole through the deck slightly oversize and down into the foam core about 2" deep. Then you want to rout out the foam under the perimeter of the hole about 3/4" all around. This is best done with a stout allen wrench. Chuck the long end of the allen wrench in a drill motor, pull the trigger and work the short end around inside the hole to loosen up the foam. Vacuum it all out clean. This way your epoxy plug will extend under the deck all around.
Fill the void you created with thickened epoxy. Use a sacrificial bolt of the same size and thread as the desired finish bolt, but use a hex head bolt so you can easily remove it after the epoxy cures. Coat the threads in beeswax, silicon, or other release agent so you don’t glue it in. Set it in the uncured epoxy until it sets, remove with a wrench, then replace with the desired finish bolt (probably a oval phillips head) This will leave you a strong threaded hole to run the final screw in. Bed it in epoxy also. For added strength you can also embed a nut and washer in the bottom of the hole. This is what I do for mounting things like T-tops.
Cross section…
Capt. Larry Teuton
Cracker Built Custom Boats
“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
^^PRO TIP^^
'06 Mckee Craft
184 Marathon
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Larry never ceases to amaze.
“Apathy is the Glove into Which Evil Slips It’s Hand”.
Larry,
Thanks for the very detailed reply! That is very helpful! I do have a couple of other questions: First, is there any reason not to use 316 stainless 1/4-20 bolts for the final fasteners? Second, what epoxy filler do you recommend? Last, do you think I need the embedded nut and washer for this grab bar application?
Thanks very much,
Tom
Welcome 
1/4 - 20 316 is fine, that’s what I show above. I use the washer and nut for T-tops and high load fittings. How tall and wide is the grab bar, how many connection points and spacing of them? The more leverage it has, the stronger it needs to be. Can you post a picture of what you have in mind?
Capt. Larry Teuton
Cracker Built Custom Boats
“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
Much like this one made by Bob van Gundy for a forum member:
http://old.charlestonfishing.com/forum/topic.asp?TOPIC_ID=148376
OK, for that, with 4 distrbruted mounting points you could skip the nut and washers. It will be strong enough without them.
I would thicken the epoxy with a mix of wood flour and ground glass fibers.
Capt. Larry Teuton
Cracker Built Custom Boats
“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
I’d rather see round or oblong bases with 4 bolts each, rather than the 2 bolt base plates. If you are having it built, request 4 bolt mounting on each leg.
Capt. Larry Teuton
Cracker Built Custom Boats
“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
You share some fantastic info, Larry!
A real bonus to CF!
Thanks you Sir.
NN
07, 23 Key West, Twin 115 Yammys
“Coastal Bound”
Appreciate it Glenn. CF shares a lot with me too. Got to give if you’re going to take. What goes around comes around in this world.
Capt. Larry Teuton
Cracker Built Custom Boats
“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
Larry,
Thanks again–I really appreciate the advice! I now have a very clear picture of just how I want to mount the grab bar–now just need to get it built.
Tom
This is great stuff. Thanks Larry. Someday I will need this info 
2000 SeaPro 180CC w/ Yammy 115 2 stroke
1966 13’ Boston Whaler w/ Merc 25 4 stroke “Flatty”
www.ralphphillipsinshore.com
quote:
Originally posted by Cracker LarryI’d rather see round or oblong bases with 4 bolts each, rather than the 2 bolt base plates. If you are having it built, request 4 bolt mounting on each leg.
Capt. Larry Teuton
Cracker Built Custom Boats“Ships are the nearest things to dreams that hands have ever made.” -Robert N. Rose
I normally use a 4 hole mounting pad(sometimes a round 3 hole). but this was made to customer specs.
Bob Van Gundy
Marine Designs,Inc.
Custom Aluminum Fabrication
803-727-4069
quote:
Originally posted by boykintomLarry,
Thanks again–I really appreciate the advice! I now have a very clear picture of just how I want to mount the grab bar–now just need to get it built.</font id=“red”>
Tom
I’m just a phone call away. 
Bob Van Gundy
Marine Designs,Inc.
Custom Aluminum Fabrication
803-727-4069
And I’m going to call you today! Good Morning, Bob!
Man that sure beats driving a 20 penny nail in and bending it over under the boat.
That was my alternate plan.
well…
we use these and 5200
http://www.boatersland.com/grl21021.html?gclid=CNTszYjhycMCFQ4S7Aod8k8Aow
strongest application we have found, can be sealed, completed instantly, fast and neat
Taking the boat up to Bob’s today to measure for the grab bar. When I start the installation, I’ll try to post some pics of the epoxy bedding process to show how it turns out.