Advice for grinding out and tabbing in a new bulkhead

[michaelapk]

Looking for some guidance on preparing the inside of the hull for tabbing in a new forward bulkhead. Had a previous post and replies convinced me to replace rather than try to repair.

'83 Ericson 30+ with wet-rotted forward bulkhead in an empty space between the v-berth and the anchor chain locker pan. Today I removed the old piece in entirety by using an oscillating saw to cut through the tabbing. I know that I have to grind down the raw edges to be able to lay in new fiberglass tabbing. I've never had to use an angle grinder before or to do this kind of repair but went at it with a grinding wheel and flap wheel.

The question: Do I need to grind the old tabbing totally off or can I leave the pieces that are expoxied against the hull so long as the perpendicular parts (that project in from the hull) of the tabbing are ground away? It looks like it could be hard to not damage the hull if I grind them all flush with the hull and not sure that is going to be necessary to get new tabbing tape to adhere. I have already ground enough so that the surface is clean.

I've found that the bulkhead wasn't adhered directly to the hull - just tabbed in place. My plan is to use a filet of thickened expoxy to hold the new piece of wood in place and then use two layers of tape on either face of the wood, staggering the tape 60/40 so that the joint is a bit wider than the tape.

Would appreciate hearing any tips or critique of the proposed approach before I go to the next stage of the repair.

Thanks,

Mike

 

[ggrizzard]

The original builder probably didn't "bond" the bulkhead itself to the hull so as to avoid
squeaking when the boat flexes.
I refer you to "Boatworks Today" on You Tube for Andy's many bulkhead replacement videos
on the subject.

 

[DrJudyB]

Here’s a video from SailMagazine and west Systems

DIY: West System Installing the Bulkhead Video 6

In this video, West System Epoxies’ tech advisor and veteran sailor Bruce Niederer Gutzmer uses a number of different tools and techniques to install a new fiberglass-reinforced bulkhead in the tech center’s J/22 project boat. For additional information or to contact the tech center directly.

www.sailmagazine.com

 

[FastOlson]

I've found that the bulkhead wasn't adhered directly to the hull - just tabbed in place.

Directly tabbing the bulkhead to the IS the correct way to connect/adhere it. Ericson tabbed most all of their interior parts, and it created a strong structure. My '88 boat has all the parts, frp and plywood, tabbed in -- bottom, side, and top.
You should post over at your owners' site, with pix.
www.ericsonyachts.org.
There are a lot of active owners of sister ships posting there.

 

[PaulK]

Builders often leave a space between the actual bulkhead and the hull so it doesn't create a visible "hard spot" in the hull. Some may use foam wedges to hold the bulkhead in place and create a surface for the tabbing to curve up against. The tabbing spreads out the load of the bulkhead so there's no hard spot and still holds the bulkhead from moving. Leaving some of the old tabbing in place may be helpful in getting the new bulkhead in the right position, but you're going to have to glass over it to provide the strong bond the bulkhead needs, so it will really only be adding weight where you don't want it.