Necky Manitou 14 thigh brace bolts stuck

I have a Manitou 14 and the bolts that hold the thigh braces on are stuck. They are the T-nut type and they all spin in place when I try to undo them. Has anyone else had this problem? I have tried needle nosed pliers and multigrips to no avail.
Any tips or tricks?

I am hoping to avoid damaging the foam or drilling them out.



Try some penetrating oil.

No joy with the penetrating oil.

I’m thinking of trying to cut a groove into the back of the T-nut so I can get a flat bladed screwdriver in there?

They are screwed in from the top?

I had to look up what “T nuts” are, and on seeing how they work, I think you are out of luck trying to salvage them and to get them apart. Penetrating oil has no prayer of being successful when a nut such as that is anchored in something as soft as foam. Even the best penetrating oils don’t eliminate the need for a lot of torque when breaking stuck threads loose. My guess is that drilling or grinding the exposed bolt head will be necessary, letting you punch the remainder of the bolt (and T nut) out the back side.

Cutting a slot for a screwdriver in the T-nut might be possible, but unless you have a circular cutting wheel you will end up cutting a much longer notch within the foam. And of course, cutting a notch will only work if the end of the bolt is not in close proximity to the back side of the nut. If the bolt goes most of the way through the nut, your screwdriver notch will be incorporated into the bolt too, making it useless.

Yeah, tried grinding a notch on the back with a Dremel. Glad I was wearing safety glasses. Having your head inside the cockpit when a grinding wheel explodes is… interesting.

Definitely going to have to drill them out and then find a similar stainless T-nut with a notch in the back.

Really need a entire face shield when grinding .

Hold the nut from spinning with a friend and a screw driver on the other end, the use a drill bit about twice the diameter of screw. Drill in short taps of the trigger on the drill, and quit when the flange is loose. The screw and stem of the nut should then slide out toward the screw head. What you are doing is using the drill to cut the flange from the stem. You do not want to drill into the foam.

What’s the other side look like? I’m favouring drilling it out, and if the other side is a Philips head it is likely easiest to go from that side. If you use a drill just slightly larger than the threaded portion, the head will pop off just as you get through it. You might want to spray a small amount of water to cool it so it doesn’t melt the surrounding plastic and make s mess. Slow RPM, decent pressure, SHARP drill.

I agree with Sparky. Not only is drilling from the inside likely to be much more difficult, doing so to remove the flange from the stem still leaves the stem of the T-nut frozen to the bolt, and that part is going to be too big to go through the bolt hole in the hull. Drill the head off the bolt (which is likely a Phillips) and all should go well, though you are still likely to need to grip the T-nut to keep the whole fastener from spinning.

Yes, stainless screw outside the cockpit. I’ll have to be careful heat wise, stainless is tough to drill.

If too tough to drill, a grinder, followed with a good sharp file to finish up the process would be a good backup plan. I’d keep a good volume of water flowing over the spot when using a grinder so the metal does not heat up.

Any iron-nickel alloy (30x stainless steel) is tougher to drill than carbon steel. But most of the problems experienced by lay people are because they are spinning a dull drill way too fast and allow heat to build up. This causes the material to get very hard and then the drill can’t cut through it. The other problem is not enough pressure. This causes the drill to rub instead of cutting and also results in hardening of the material. This is why I suggested SLOW and SHARP with moderate pressure.

Of course, Guideboatguy’s comments on using a grinder are equally valid. It’s just perhaps more risky if the grinder gets away on you or you can’t control the heat enough to prevent melting.

Plenty of experienced folks giving advice here which sort of brings up another issue, which is preventing this from happening next time. I’m a believer in coating threads with grease or anti-seize compound for stuff that’s out in the weather. I’ve never had a greased connector end up being stuck. Even 20 years later when everything else is rusty, greased connections come apart about the same as they would have on the day of assembly.

Thanks for the advice and suggestions, much appreciated. I will definitely go the drilling route.

The boat is second hand and the bolts are as they were when the boat was made. The previous owner never moved the thigh braces. A bit of grease on the threads is a good idea.

Finding replacement bolts is the first step I guess which could take a while (in Australia).