Tabernacle pulled from cabin roof

[islandjim]

On my Oday 22' during a test mast raising, one of the helpers fell off the boat bringing the mast with him. However, the mast was already in the tabernacle and the force pulled the tabernacle from its mounting. The mounting screws looked like #12 X 1/2" machine screws. There were only four of them. This doesn't seem like enough holding power for the base of the mast. It may be, but it doesn't look strong enough. My plan is to drill 4 new holes and use an 1/8" longer screw which I don't believe will go through to the inside of the cabin. Being there was no fiberglass damage and the screws had just pulled free from the fiberglass, I feel that 4 new screws in different locations should solve the problem. Can anyone give me any feedback or support?

 

[Ross]

I would repair the torn out screw holes and reset it in its present holes. The tabernacle isn't supposed to have to support lateral loads so having it pull the screws out doesn't surprise me.

 

[JerryA]

A friend had the same happen last fall when tearing down. He used the same holes. Cleaned out the holes and surrounding area, filled with epoxy, redrilled.

JerryA

 

[sailormanbigd]

tabernacle

If it was me i would drill thru inner liner-provided there is clearence inside and then thru bolt the base using a good 3m adhesive. My od25 is done that way using castle nuts inside with ss washers. So the next time it happens it will bend the mast.

 

[Nereussailor]

If it was me i would drill thru inner liner-provided there is clearence inside and then thru bolt the base using a good 3m adhesive. My od25 is done that way using castle nuts inside with ss washers. So the next time it happens it will bend the mast.

That doesn't sound like a good idea, it's cheap and easy to repair the fiberglass, but the mast will cost you big bucks. I'd stick with the original setup.

 

[islandjim]

Whenever you have a question or concern, it seems that you can usually find the answer right here. Being the factory thought small screws were all that were needed, we will follow the factory design, afterall it lasted for over 30 years. I will epoxy the holes, insert the screws, and add two more screw just for peace of mind. I see no need to go through the cabin liner and open the door to all sorts of problems. I have all the repair parts and will attack the project this evening.

I would like to thank you all for your information.

 

[BobM]

It is really the shrouds that are holding the mast up. The tabernacle is, as others have stated, not necessarily up to the force that can be imparted by a lever as long as your mast. Does your tabernacle have a slot in it to allow the mast to pivot or a built in pivot plate. If not, it may be worth upgrading it to one, since you are going through the motions anyway to refit the existing one. A stainelss plate with attachment points for turning blocks is a handy addition too.

 

[Benny]

Fill with epoxy and redrill is proven fix.

 

[jibes138]

Screw threads in epoxy

Threading directly into epoxy or in to FRP is a very bad idea. The threads have extremely low strength. Granted the original design did not apparently require a lot of strength it still seems there is a lot of shear on the tabernacle during the mast raising process. My recommendation for what its' worth is to install screw thread inserts into the FRP and epoxy those in place, this gives a much larger surface area for the epoxy to bond, use a knurled type insert, then use machine screws to hold the tabernacle to the inserts. The best bet is to glass these inserts in place but that adds a lot to this repair.

 

[jibes138]

here's a picture of an insert from a company called penn emgineering used for plastic injection molding. They are called PEM inserts. I'm sure other companies have similar products.
Insert something like this in the hole put some release agent on the screw and thread it into the insert, then fill the hole with a thickened epoxy. This will be far stronger than just the epoxy with basically a wood screw.