Smart Tabs Failure: Machine Screws Sheared Off in Transom

[soundview]

Approximately two years ago I installed a set of ST1290-80 Smart tabs in my 21" Mariah Talari. All directions were followed and I used only the materials provided for the install. The other week I noticed that the two of the screws that bolt the tabs to the transom were missing. The missing screws were those two closest to the outdrive on the port side.

I assumed at the time that they had been stripped out or had worked themselves out but when I checked the other day, they had sheared off about 1/2 inch into the transom. All other screws are solid and intact. No damage to the tabs themselves and I have never hit anything that would have caused the damage. My trailer has plenty of clearance for the tabs so that is not an issue, either.

Any idea of what would have caused this? Any thoughts on repairs?

Boat is a 21" Mariah Talari 5.0L V8 I/O w/ an Alpha One/Gen 2.

Thanks,

SV.

 

[spoilsofwar]

Re: Smart Tabs Failure: Machine Screws Sheared Off in Transom

You said all instructions were followed, but just to verify, you installed those particular screws by hand, with a screwdriver, and not with an electric drill, yes?

All I can think of is they were overtorqued, faulty from the manufacturer, or a combination of the two.

As for repair, extract the remainders if possible, drill out if not possible, fill, and rescrew.

 

[nlain]

Re: Smart Tabs Failure: Machine Screws Sheared Off in Transom

The only thing I can think of would be either defective new or over torqued. Hope you used 4200 and not 5200 sealant.
If you go to drill them out and have a reversible drill motor, go buy a set of reversible drill bits. start small and then go larger, reverse bits will sometimes catch in the metal and spin the broke part out.

 

[robert graham]

Re: Smart Tabs Failure: Machine Screws Sheared Off in Transom

Maybe good to remove trim tabs, inspect and seal all old screw holes with 3M 5200, move trim tabs left or right about an inch and drill/screw/install there, so you'll be in "new" transom area....maybe larger screws this time with some sealant or adhesive to help hold trim tabs on very tight? Good Luck!

 

[soundview]

Re: Smart Tabs Failure: Machine Screws Sheared Off in Transom

Thank you all for the quick replies & good suggestions.

The screws on the original install were all hand torqued. The only power tool used was a drill to make the original holes in the transom. I checked the remaining screws and snugged them all in a bit with a screwdriver...they all felt good.

I did use 4200 with the install, thankfully! The sheared screws seem pretty well lodged in the transom, so I may clean out the holes with a slightly overlarged drill bit down to the screw shafts and seal those two cavities off with 5200. There is an inch or so of metal between the screw holes on the hinge plate, so an option would be to keep the original screw holes and "walk" the other two over half an inch and drill new holes through both the hinge and the transom and use longer machine screws, maybe 1" instead of 3/8".

Any thoughts on this plan? Also, what is that "sealing tape" that was used? Anything comparable I can pick up at a Lowes or marine supply shop?

Thanks!

SV.

 

[robert graham]

Re: Smart Tabs Failure: Machine Screws Sheared Off in Transom

Sounds like a plan...anything you can do to secure those Tabs would be worth trying. Maybe check around the Boat/Marine Supply places for additional bright ideas? Must be a lot of stress back there at higher speeds? Good Luck!

 

[nlain]

Re: Smart Tabs Failure: Machine Screws Sheared Off in Transom

Sounds like a plan, the only thing I would change in filling the holes is I would use Marine Tex Epoxy instead of 5200. I feel like the epoxy would be stronger repair, there will be a good amount of pressure near the existing holes, do not want possible weak spots in transom. Just my thoughts.

 

[soundview]

Re: Smart Tabs Failure: Machine Screws Sheared Off in Transom

nlain, good idea with the Marine Tex. I'll use that in the sheared screw holes.

Thanks, all.

 

[Lowe170]

Re: Smart Tabs Failure: Machine Screws Sheared Off in Transom

You could also call/contact Nauticus customer service for advice; nothing but great things heard about them on this forum from what I've read.

 

[Dabbler_E]

Re: Smart Tabs Failure: Machine Screws Sheared Off in Transom

+1 on Nauticus' good customer service. One of my actuators got water in it, and they replaced it no questions no problem.