Need help on Grady construction

[Halfhitch]

I removed the seat boxes/tackle storage things that the previous owner had installed and bought a pair of Garelick adjustable pedestals so I can have my cockpit back.
I had hoped that it would be an easy matter of screwing the bases right back in the old holes but evidently Murphy was watching and he is back at his tricks. It's obvious that the guy that removed the seat bases in order to install the tackle boxes had a problem and had to cut 3 of the screws off flush with the deck on the port side. In running a pick down inside the open holes I can feel metal in the bottom and it feels like it is threaded. I'm wondering if anyone knows if that is a continuous ring under there sandwiching the deck or if it is individual threaded tee nuts that puncture into the deck wood to hold the torque. I suspicion tee nuts that were spinning when the removal was attempted. Just wondering if struggling to get the broken pieces out is worth it. And if it's individual tee nuts it's probably not doable. Normally I would just split the difference between the old holes and drill a new set but I would like to know if there is a continuous ring down there before I start. Any thoughts or ideas are welcome.

 

[ocnslr]

Lift the hatch. Good time to inspect and clean underneath. GE Silicone II in almond matches well.

And that base needs to be through bolted, not screwed down. If you lift the hatch you can fabricate your own backing plate, then use fender washers and locking nuts.

 

[DennisG01]

The gas tank is under that hatch. Depending on how tall the gas tank is in regards to the depth of the coffin, there may not even be enough room to cut an access hole through the stringer (without removing the tank). But even if there was enough space, you're still cutting a hole through the stringer, and then have to get rid of the foam that will be in the way. Doable, but probably not necessary.

I know that some boats, like Sea Ray (have personally seen it a number of times), use a ring. But I do not know what Grady uses. In the 3rd and 4th pictures, it almost looks like we're seeing part of the t-nut (the vertical section, not the "brim" of the top hat). However, how about just drilling a small (1/8") hole through the deck to find out? Drill it in one of the spots where you would "split the difference" just in case you want to use that as a pilot hole.

I agree with OCNSLR - you want to through bolt. Google for "Toggler Snaptoggle". Although you'll still need to get a bent nail or allen key down there to ream out the foam... maybe some carefully used acetone to melt it away.

If you do go through the coffin, you can get your hand in there to use a backer plate and nuts. But you'll want to re-glass the hole you cut in the stringer, along with using a good deck plate and sealing it's mounting screws really well.

 

[SkunkBoat]

you can buy a flexible snake camera at Harbor Freight so cheap that its ridiculous.

As you said, you can rotate to between the old holes and re-drill and use stainless mollies(toggles)
Garelick makes stainless specifically for blind mounting pedestals.I've done it that way before

You can drill a 4" hole in the middle and have a hand size access, put in new t-nuts or epoxy in some backing.
Once you mount the pedestal the hole is covered. I've seen it done it that way.

stay away from the stringer.

 

[Halfhitch]

I have an inspection camera. I will stick it in there tomorrow and take a few pictures. Just feeling around from the center hatch it doesn't feel like there is any gap there.

 

[SkunkBoat]

I have an inspection camera. I will stick it in there tomorrow and take a few pictures. Just feeling around from the center hatch it doesn't feel like there is any gap there.

you might get a look thru the rod holder hole?

funny, just saw a borescope camera online that connects to cell phone for $13....when will it stop????

 

[DennisG01]

Skunk, totally forgot about drilling the 4" hole... shame on me!

FYI, you can buy backing rings in two pieces so you can get it down through the hole.

I'm sure if you call Grady on Monday, they can answer your question about construction.

 

[Halfhitch]

I have an inspection camera. I will stick it in there tomorrow and take a few pictures. Just feeling around from the center hatch it doesn't feel like there is any gap there.

you might get a look thru the rod holder hole?

funny, just saw a borescope camera online that connects to cell phone for $13....when will it stop????

That's the kind I have. It plugs into my phone and I can record still photos or video. I got it on Amazon for about $25. It has about 10 feet of length'.

 

[Halfhitch]

you can buy a flexible snake camera at Harbor Freight so cheap that its ridiculous.

As you said, you can rotate to between the old holes and re-drill and use stainless mollies(toggles)
Garelick makes stainless specifically for blind mounting pedestals.I've done it that way before

You can drill a 4" hole in the middle and have a hand size access, put in new t-nuts or epoxy in some backing.
Once you mount the pedestal the hole is covered. I've seen it done it that way.

stay away from the stringer.

That's sounds like something to consider. I will do a little research with Garelick.

 

[Fishtales]

Hi,
I'd pull the hatch first. You need to know what you have under it and how much clearance you have. If you drill blind, go slow and be careful.
One assumption your making with drilling a center hole is you are able to re-use the backing plate which might not be the case. Before drilling, I'd suggest getting as much data as you can on what is behind it.

 

[SkunkBoat]

If you have the space, toggles are the simplest, quickest solution.

you'll definitely get a look at it thru those rod holder holes.
Also look at the diagrams of you model from the grady website. See if there is a pvc tube running thru there.
Most likely your only problem will be foam that leaves no space for the toggle bolts to flip.

Thats where cutting a 4" hole with a hole saw bit comes in. you can control the depth to just cut the deck. don't use a saws-all or a jig saw.
once you have access, you can dig out the foam and use t-nuts. you can also add backing thru the hole. wiggle some strips of ply or aluminum in and glue them up to the bottom.

 

[Halfhitch]

Well, I sent an email off to Grady White today asking them about what's under the pedestal and what type of attachment system they used back then. I also asked them if they could offer a suggestion as to the most desirable method to be sure and retain the fit and finish up to Grady standards. I'll see what comes back.

I put that camera under the deck from the center hand hole and from the side rod holder but from both directions the deck or sole is down tight onto a bed of adhesive on top of the stringers. Looks to me like I have to do it from the top only.

This is looking from the center handhole. Looking starboard.

This is looking starboard from the port side rod holder.

 

[DennisG01]

I believe I did mention that you can't go in through the gas tank coffin without cutting a hole in the stringer... but then I suppose you wouldn't have had a chance to play with your snake... It makes sense that you couldn't get in through the rod holder since if you could, then any water that made it's way in there would make it down into the floatation foam and could fill the cavity under the floor.

If you don't want to wait for Grady, just drill that 1/8" hole I mentioned and you'll know right away, in less time than it's taking me to type this response, if you have t-nuts or a glassed-in ring. If you have a ring, you can tap threads. If you have t-nuts, you're back to the 4" hole. Either way... easy peasy.

 

[Fishtales]

Well at least you know what you are up against. I'm thinking the center hole is one way but you have no lateral access. I'd want GWs input before you start the process. I'm thinking a hole saw and going real slow if you have to go through the deck. It is a blind cut which sux. The thing that would have me nervous is getting the material out cleanly without damaging what is underneath. You may have to have the bolts come through the floor and tighten down on the base which is not optimal. You'll have to come up with a way to address so it looks good and doesn't cut skin. It would be nice to get a metal disk between the deck and the based to allow you to seal the area and give additional rigidity.

If you pull the deck and go in laterally, it may be tough at the beginning as you have to create access, but you are under the deck and can likely epoxy things back together when done. You may be able to seal the center hole (if still needed) better as you have some backside access. You would be able to get your bolts to tightened on the underside which is huge for a clean installation. Finally you don't lose access once the plate is installed.

Going to be interesting to see how you play this.

 

[SkunkBoat]

http://www.garelick.com/Reinforcement-Angles-For-Seat-Bases can be done thru 4" hole

http://www.garelick.com/Reinforcement-Rings-For-Seat-Basescan be done thru 4" hole

http://www.garelick.com/Toggler-Brand-Stainless-Steel-Toggle-Bolt-Anchors

Looks like the rigging tube is off to the port side from your seat location.
You can drill a hole just big enough to get your camera in (is it lit?).
DON"T drill the small hole dead center because you might need to use a 4" hole saw bit later and you want the center drill bit to bite!
Drill it where it will be cut out with the 4" piece.

If there is room for toggles to flip, that is your easiest fix.
Otherwise, 4" hole and reinforcement angles.

 

[Halfhitch]

Hey skunkboat, thanks a million for finding that drawing of the rigging tube layout.(where did you find that) Those links you attached are the things I have been looking at. I am thinking the same as you as the most desirable route to take. I haven't got an email back from Grady yet but with the drawing you found, I feel ok about drilling through. I also think that the toggle bolts are the way to go. I can't tell exactly how they work as far as how they keep the threaded under-deck piece in place while you thread the bolt in and should the seat be removed at some point what keeps them in place. I do know that Garelick makes pretty good stuff so I'm sure they work fine. I will avoid the hand hole method if possible but if that becomes necessary, I appreciate the thought about not wrecking the pilot hole locate.

 

[DennisG01]

I also think that the toggle bolts are the way to go. I can't tell exactly how they work as far as how they keep the threaded under-deck piece in place while you thread the bolt in and should the seat be removed at some point what keeps them in place.

Did you try googling for the brand I mentioned above? They used to have an installation guide right on their website.

Have you done any exploratory surgery, yet? Like drilling that pilot hole mentioned above to check for a metal plate?

There's not going to be anything in the way if you drill in the area you want to put the seat base. It's just standard boat construction when using stringers. There won't be a bulkhead there. Toggles or 4" hole... makes no difference. Honestly, the 4" hole is probably easier - as I mentioned above, the thing you're going to have to deal with is getting rid of the foam - it may not be "tight" to the underside of the deck in all areas, but it very well could be in some spots. Getting rid of the foam through a 4" hole is much easier than through 1/4" holes (I think I mentioned a way to do that above, though... still kind of a pain).

 

[SkunkBoat]

Hey skunkboat, thanks a million for finding that drawing of the rigging tube layout.(where did you find that)

http://www.gradywhite.com/the-grady-experience/owners/owners-manuals/


The toggles are held in place by those plastic things until you get the bolt started. They will fall out if you unscrew them and you'll need to but new ones.
You can try gobbing silicone on them when you put them in, you might get lucky.

Sometimes you can't even get them out because once the bolt is really loose, they spin. You have to pry up while unscrewing. worse case you have to cut the loose bolt.

You could use one of those plates. where the plate gets bolted down to the deck then the seat base screws into that. More $ but allows you to remove pedestals easily.
(You need to grease those screws regularly or they will seize in the base plate.)

 

[Halfhitch]

I spoke to Grady customer relations today and found out that the deck is 1/2 inch plywood with flat washers and nuts installed before the cap was landed on the hull. Carolyn said it's ok to drive the sawed off bolts through and install toggle bolts. They are on order. Meanwhile I got some non skid pattern flex mold from Gibco and will attempt to repair the damage to the sole gelcoat from that beastly 5200.

By the way Skunk, I tried that link to the Grady manual and it will accept my year and model but will not give me anything. I have tried that before by going to the grady website and I can never get it to work. If you can get it maybe you could email it to me.

 

[Legend]

When I have downloaded manuals, I always get a small message on the bottom of the screen that asks for your permission to download PDF files.