Broken screws in the transom

[retiredDon]

1998 Wellcraft Coastal both trim tabs have broken screws on them. On the port side which is completely off we have 6 screw holes. 3 screws are out and 3 are broken off just under the fiberglass where you cannot see of get a grip on them.

2 part question. 1. what is the best way to remove these screws. I cannot get to them on the inside of the boat to drill them out and add a thru hull nut and bolt. If I make the hole a little bigger to try and dig in with needle nose can I repair it strong enough to replace my trim tabs? Or do I fill each of the bad holes put the plate back on with the 2 good screws and drill new holes in the steal plate into the transom?
2. I notice on the port side one of the screw holes goes completely into the bilge. Would marine tex work to stop that leak?

Any advice appreciated as my short season is getting shorter with the boat on land.

Thanks
Don

 

[ondarvr]

Drill them out, you might bugger the hole up a little, but that's OK. You can fill the holes with epoxy and then redrill as needed.

 

[jigngrub]

Trying to drill out screws broken off in wood is nearly impossible, the bit will slip off the harder steel screw and go into the wood seeking the path of least resistance... or at least that's what happens to me, I end up drilling beside the screw instead of drilling the screw out.

I'd patch over all the old screw holes with a marine epoxy like marine tex or loc-tite marine epoxy and move everything over to the left or right a half inch and drill new holes and use new screws. I suggest stainless steel sheet metal screws in #12 or #14 size 1-1/4" to 1-1/2" long.

 

[Grandad]

I agree with jigngrub. The exact position of the tabs is arbitrary and probably not critical. The only concern I would have is that if this was not noticed and corrected soon enough, the entire area may have rotted out from continuous water intrusion. Remounting in a slightly new location may give an opportunity to "test" the integrity of the transom at the new screw holes. - Grandad

 

[gm280]

I have a little different approach to this. You can buy a small hole saw bit that will allow you to both drill out the screw that is in there and see if there is any rotted material around that broken screw. Use a Hole saw that is just a little larger then the screw and then the plug will be removed to allow you to verify any rot. And if it is good dry material, then epoxy the hole up and after it cures, you can easily drill it out for a new screw. And by doing that, no water will ever get into the wood again because the hole will be filled with epoxy and the new screw will not be anywhere close to wood. And some folks actually do that very same idea when installing their engines to the transom. They drill the bolt holes larger then needed and fill them in again with epoxy or poly resin and then drill that resin filled hole to the proper size. And there is never any water intrusion doing that... JMHO!

 

[ondarvr]

The correct repair is to drill out the broken screw and go back in the same hole, here's the reason.

Typically the tabs are mounted in the position where they are most effective (not always though), so there may be a reason for their placement.

The screws most likely started to corrode, then weakend and broke, this normally means that water found it's way into the hole, this equals wet wood. Rusting screws tend to have bad wood around them, which will rot over time. frequenlty by the time the screws break the wood has started to rot. So leaving the pieces of the old screw can create future repairs

By drilling out the old screw and the surrounding possibly wet wood you now know what you are working with, and can remove a bit more wood if needed. So having the hole oblonged by getting the old screw isn't an issue.

The correct, but time consuming, and not frequently done, method of mounting things in a core is to drill an oversized hole, fill it with epoxy, then drill it for the correct sized fastener.

By using this method you have removed all the possibly wet and degraded wood, put the new screws in correclty, and left the tabs in their original position.

Not doing it this way leaves the chance of having rotting wood and metal left in place, then you compound it by drilling new holes that can suffer the same fate. If you are going to do the new holes correctly, then just go back and use the old holes correctly.

 

[Woodonglass]

An old wood working trick for removing broken screws from wood is to use a piece of 1/4" pipe and file some "Teeth" into one end of it. Then chuck it up in your drill and drill Around the screw. You can use a small screwdriver to pop the wood plug out and then glue a piece of wooden dowel back in place and put in another screw.

 

[gm280]

An old wood working trick for removing broken screws from wood is to use a piece of 1/4" pipe and file some "Teeth" into one end of it. Then chuck it up in your drill and drill Around the screw. You can use a small screwdriver to pop the wood plug out and then glue a piece of wooden dowel back in place and put in another screw.

Good picture WOG. That IS what I was trying to convey. If you drill the hole out larger, then you also drill out any rotted wood (hopefully) and remove all the rot if any. Then I like to polyester the hole with Peanut butter and re-drill the new hole. Then there is no more rot and never will be any again... ondarvr hit the nail on the head like I was trying to say. And WOG , I like those hole bits and will have to make a set on my lathe... :thumb:

 

[Grandad]

An old wood working trick for removing broken screws from wood is to use a piece of 1/4" pipe and file some "Teeth" into one end of it. Then chuck it up in your drill and drill Around the screw. You can use a small screwdriver to pop the wood plug out and then glue a piece of wooden dowel back in place and put in another screw.

Has anyone used these without a centering bit? I'm sure you would need to use an easily-made template of perhaps plywood with a pre-holesawn hole the size of your core bit clamped in place. Without some guidance for such core bits, they'll tend to wander around the face of the transom before finally settling into one spot.
- Grandad

 

[jigngrub]

they'll tend to wander around the face of the transom before finally settling into one spot.
- Grandad

... and probably not the spot you want them to drill in either!

I don't see any need in futzing around and making a hole bigger in a transom just to dig out a broken screw. You're going to have to patch up the hole and then try to get another screw to hold in that same patched hole. Just skim the old hole over with epoxy and forget about it.

If the tabs are Smart Tabs, you can move them up to an inch left or right without any problems.

If the tabs are hydraulic or electric you can leave the tabs in the same place and just drill new holes in the tab mounting bracket.

 

[Woodonglass]

Tis' True... You do need to use a Centering jig when using the plug cutters!!!

 

[ondarvr]

It's not hard to use one without any type of jig or having it move around, just use the same or next size twist drill to start the hole and the insert the plug cutter into the hole.

It isn't hard to do it right and not have to worry about it again, or having it rot. Without a pic we have no idea if they can be moved easily, and really there's no need to.

 

[Woodonglass]

I don't know nuttin about trim tabs and their location, just tryin to help with the removal of busted off screws and such. Once the screw is out and the new hole is created filling it with thickened resin, and fibers or a wood dowel and epoxy or other type fillers is the Owners choice. I'm just trying to come up with options per the OP's original question on how to remove a broken screw??

I just read this on another boating forum. Seems like an excellent idea..."This is a common problem with a lot of messy solutions, here's one that works for me. Get yourself a roll-pin with a center hole just slightly smaller than the fastener you're trying to remove ( a roll-pin is a piece of very hard steel that is rolled into a pin). The roll pin is split down it's length, what you need to do is grind a couple small teeth , like on a hole saw except backwards so as to make this cut in reverse. Chuck this in a reversible drill and carefully center it over the broken faster, with low-speed and steady pressure drill into the fiberglass in reverse. The roll-pin will grab the fastener and remove it leaving a slightly larger hole only deep enough for the pin to grab the fastener."

 

[retiredDon]

Thanks for all the great information. To be honest I thought about drilling the hole a little bigger and filling it in. My concerns were should I do it for all 6 holes on each trip tab? Although only 3 are sunk in on both sides I broke off 2 more and were able to get the remaining part of the screw out. I'm a little nervous that after making these hole will I be opening a can of worms and will I be able to fix it. I also worry that if I put new screws in the same spot will it really have the same strength. I think the safest way maybe getting the boat yard involved this way if the screw it up I have some recourse.

I do have to say you guys did give a lot of information. Thanks again I'll let you know how it works out.