Yet another deck core replacement example

[tenders]

The foredeck of my ‘69 E32 became increasingly disconcertingly springy to the step, so this was the year for the repair. This is the fifth section I’ve done with my long suffering boat partner, which include the cockpit floor, the mast step, an area around the main hatch, and the port side deck. The starboard side deck was the first such repair, done by a pro probably eighteen years ago - he didn’t use this method and it needs to be redone next year. Here’s how I do these - always from above:

1. Mark off a perimeter 2.5” inside the area I want the repair to show
2. Use a diamond blade on an angle grinder to cut along the perimeter of the upper fiberglass skin, taking care NOT to cut more deeply than 1/2”
3. Slice the area to be removed into index-card-shaped fragments as necessary, as some of the balsa core will still be firmly attached to the upper skin
4. Pull, crowbar, and otherwise yank the fiberglass skin off - some comes very easily, some comes with great difficulty
5. Scrape out the remaining core with an oscillating saw, and also dig out the old core under the perimeter of the repair wit whatever poky tools you can muster (I used a small Harbor Freight catspaw this time)
6. Sand the base smooth (the lower skin of the fiberglass sandwich)

This marks the point of “maximum entropy” in the project. It isn’t difficult. Maybe takes 2 hours If you’re focused? I’m not, usually. Sometimes the remaining core is wet and the job is a little easier if you let it dry for a while.

The major replacement parts:

1. Cut one or more pieces of replacement 1/2” foam core and 3/16” G10 panel to drop into the hole. Check this fit. I used a cardboard template. Cutting the G10 is the hardest part of this job. This time I used a carbide blade on a battery-powered Makita mini circular saw, but a carbide blade on a table saw works better.
2. Grind 2” bevels around the perimeters of both the hole in the deck and the perimeter of the G10. This is the most mindless part of the repair, because even with a grinder, G10 is slow to grind. A 2” bevel on 3/16” material is about 10.5:1, which is very close to West System 12:1 guidance. I have not had the slightest issue with this approach in these repairs.

. From there, in a single session:

1. Stuff small sections of epoxy-soaked core pieces around the periphery of the hole, replacing the core where there is still original deck above, and cutting the core flush with the hole with a box cutter you don’t care much about (the epoxy is going to get everywhere)
2. Coat the bottom of the hole generously with epoxy, slightly thickened
3. Drop the foam into the hole
4. Coat the top of the foam generously with epoxy, slightly thickened, and fill in any gaps around the edges of the foam with additional epoxy
5. Drop the G10 panel on top of the foam, weigh it down, and let the epoxy cure

Finally:

1. Adhere the new G10 to the surrounding boat by laying strips of epoxy-soaked fiberglass tape 4”, 3”, 2”, and 1” in width into the valley formed by the bevels between the G10 and the edge of the repair
2. Once cured, sand that as smoothly as you can and fair it - I did a round of Watertite, which I ran out of, followed by a round of System Three, aggressively sanding (not grinding) between rounds
3. Mask off surrounding area and coat with Kiwi Grip

 

[Loren Beach]

Really Nice Work! Thanks for the patient explanation also.

And FWIW, big projects like re-coring happen due (depressingly often) to a prior owner or owners not completely re-bedding ALL deck fittings every 20 years. (Just my opinion, BTW.)

Your attention to structural details will make your boat 'better than new'.

 

[tenders]

I think the seeds of ths recoring project - and most of the others - were sown in the blueprints. You can only keep holes drilled in balsa cored fiberglass so dry for so long. These boats were never expected to last 50+ years, and the tools we use now to prevent rot - butyl tape, foam core, G10, and epoxy - did not exist then in any accessible form.

This foredeck rot mostly came from the many holes drilled to hold a metal track in place down the foredeck. I suppose this track is for a spinnaker down haul, although it seemed more complicated than it needed to be for that purpose, or for an inner shroud or cutter rig, which is impractical. I’ve never used it but I’ve pulled it off and resealed it three times in the 34 years I’ve owned the boat. Eventually whatever was in there from long ago,prevailed.

 

[tenders]

Hmmm, can we not edit posts any more after a certain elapsed time? Guess not. Anyway, linked for the sake of completeness are the other core repair projects I've documented here and at the Moyer Marine forum.

1969 E32 cockpit core repair: an illustrated guide

E32 cockpit core repair: an illustrated guide The cockpit deck of my fine 32, built in 1969, owned and sailed by me since 1991 on three US coasts (west, north, and east), had become progressively spongier and spongier; I think the area around the fuel fill had leaked water long ago. My boat...

ericsonyachts.org

Re-core project advice - Moyer Marine Atomic 4 Community - Home of the Afourians

Seeking advice on E32 mast step repair

E32 mast step deck repair: an illustrated guide My 1969 Ericson 32, which I've owned since 1991, has a deck-stepped mast. Under the mast, just a bit to port of the centerline, is a mahogany compression post, and about 18” to the right of this is another mahogany post of somewhat less...

ericsonyachts.org

 

[gabriel]

Nice work!

I think I would get rid of my boat if I had to do this job!

 

[tenders]

I would too if this all had to be done at once, but it has all been quite incremental. The mast step replacement was daunting, I will admit, once the dust started to fly. And this would not be feasible without the inexplicable enthusiasm of my longsuffering boat partner.

We seem to do a 20-or-so hour project a year, and I’m not sure that would be different with a different boat. There are innumerable little projects that may or may not get done too - but that has been the case since I bought the boat in 1991. Considering the age of the “Ship of Theseus” parable, I suspect all boats are like this. Entropy never sleeps, but modern labor costs euthanize it.