Mast step repair- help!

[Spot]

I think you are on the right track. I would use a couple G10/FR4 'saddles' running port to starboard to keep old and new moving together when the system is in compression. Take the time to make patterns for the keel side of the saddle allowing for a snug fit when epoxied in place. Be sure to clean existing fiberglass of any blush/wax/dirt before gluing. Original design solved the problem of a bumpy bottom but its span was probably a bit much. Shorten the distance on any cantilevered loads and you will be 'golden'. You would not need a 100% perfect fit at each bump, the saddle will act like a little like an arch, just do your best and feel good about tackling the job.

[kayakerChuck]

Thanks!

My general thinking is "It's fiberglass, I can fix it." I've rebuilt 3 boats so far- floors, stringers, transoms, engine mounts.

I like the "saddles" idea. That, some heavy epoxy putty and some fillets & I'll never have to worry or think about the mast step again. :-)

The weather liars are calling for 60 degrees here tomorrow. If I had my stuff together, I could be mostly done tomorrow. I guess I'll just have to work so I have funds for sailing fun.

[wyb2]

Originally Posted by kayakerChuck

The pic looks better than what is really there. Lots of lumps & valleys and weird angles. I'm hesitant to grind much- I'd hate to find that there is a reason for the weird shapes. Building a box structure with the bottom contoured for a decent rough fit set into a structural epoxy filler... maybe? Ideas welcome!

Pick an area below the mast step, create a perimeter with masking tape and popsicle sticks, and pour in a 1/4” - 1/2” depth of thickened epoxy. Now you have a flat surface to bear down on, no trying to match existing contours. Like a miniature boat version of pouring a concrete slab.

[Spot]

Originally Posted by wyb2

Pick an area below the mast step, create a perimeter with masking tape and popsicle sticks, and pour in a 1/4” - 1/2” depth of thickened epoxy. Now you have a flat surface to bear down on, no trying to match existing contours. Like a miniature boat version of pouring a concrete slab.

I like this idea too especially with some fibers or roving or something to make it act more like a composite than a monolithic resin. I have deep epoxy only patching pours (1/2 to 1" deep) in my garage floor (how I use up extra mixed resin) and occasionally they crack in northern climate extremes.

I would also consider temps and humidity at the job site and working with a low/non-blushing epoxy.

[wyb2]

Originally Posted by Spot

I like this idea too especially with some fibers or roving or something to make it act more like a composite than a monolithic resin. I have deep epoxy only patching pours (1/2 to 1" deep) in my garage floor (how I use up extra mixed resin) and occasionally they crack in northern climate extremes.

I would also consider temps and humidity at the job site and working with a low/non-blushing epoxy.

Agree with fibers, I didn’t make it clear, but I was thinking thickened with milled/chopped fiber. My only concern with roving would be does it bridge the low spots in a way that encourages air bubbles.

On the other hand, he would be replacing an open span with basically a solid column, so even full of air bubbles it would probably be stronger than original.

[kayakerChuck]

Today's installment of "Geez, I wish I hadn't Cut That Last Piece"-

I tapped around in the bilge area just to see if it sounded solid. It sounds... hollow.

I drilled a small hole, and found about 3/8" of glass, then air. There is a void there about 3" deep.

Here I am about to probe with a small cable tie:
[IMG][/IMG]

Here's how far it goes before hitting bottom:
[IMG][/IMG]

This doesn't look promising as a load bearing area, and explains the bridge structure above. I have some ideas how to put this back together, but it's late & I'm tired. I'll put together another sketch or two.

[rognvald]

Hi, K,
A quick thought: whoever designed the mast step(probably a marine architect) did so with the build of the boat in mind. Those voids may have been factored into the equation when building the step. So, if it were my boat, I would rebuild the step as originally designed with fresh materials and beefing up(where possible) the construction. A new design without absolute knowledge of the previous construction could be a mistake and compromise overall soundness of your vessel. After all, it lasted 40 years.
Safe sailing . . . Rognvald

[kayakerChuck]

Rognvald-
Well said, I agree!

What is going back will be much like it was built. It will be stronger, mostly because I'm too lazy to learn how to do the actual calculations. "When in doubt, make it stout. Of things you know about".

As it came from the factory worked for a long time, and would still be fine if they had provided some decent drainage below the mast so the plywood core didn't rot.

I was going to build in a column because it's not much more work, and if resting on a solid surface, would add a tremendous amount of (unneeded) strength.

My other half wants me to drill a bigger hole to explore the void with a boroscope. Nope- It's dry and the area is sound. I'll fill the hole & not worry about it.

[rognvald]

"My other half wants me to drill a bigger hole to explore the void with a boroscope. Nope- It's dry and the area is sound. I'll fill the hole & not worry about it." K

Hi, K,
Make sure there's no wires/conduit/drains in the void if yo decide to fill it.
Best, Rognvald

[wyb2]

Looks like maybe they just covered up a pocket above the keel to avoid an inaccessible mini-bilge under the mast that had nowhere to drain to. Actually kinda nice of them.

I still think providing some support is a good idea since you already have it opened up. I think Spot’s 1st sketch with the green transverse ‘saddles’ is the best bet now that we know it’s a false floor. Can you tell how wide the void is (port to starboard)? Even if the new saddle just barely picks up solid hull material at the corners, it will provide immense support.