Apache Deck and Backing Plates

Deck Construction

The first Apache's were built with Plywood decks. Some had lamination issues due to inadequate resin. Second Sojourn is hull #20, built in 1968 and the previous owners report that it was one of them. In 1970, it went back to Chris Craft and a new deck was installed. Pretty amazing customer support  This recall may have been motivated by a famous photo in a late 60's book by Hal Roth. The photo shows an Apache 37 with a stove-in coachroof. It had not survived a grounding off San Francisco with subsequent waves crashing on the deck. The newer Apache decks are foam core, and amazingly strong. The foam core construction addressed the delamination problem and built a very waterproof deck. If water should leak in through a fitting, the resin-impregnated foam will not absorb it. Below is a photo of a core sample removed from the deck. Beautiful construction.

Another notable about Apache decks is that they are built of fiberglass but with a wood-grain and caulking texture made to resemble a teak deck. I understand that an actual teak deck was built and a mold was made from this wooden deck. The decks were painted teak brown with the caulking painted black. The effect is pretty amazing, with even the teak bungs visible in the surface.  35+ years later, most of these are now faded. To restore them to original they could be repainted the same dark tan and then the 'caulk' stripes painted black or a darker brown.  I find even the faded deck color to be a bit too dark. Darker decks absorb a lot of solar heat and are too hot to walk on barefoot on a hot day. My plan is to repaint the deck with a lighter beige color with a bit of non-skid added. I haven't gotten to this project yet.

This is a piece of forward deck that was removed to install a chain pipe. It shows the quality construction of the Apache 37 foam core decks. 1" of foam core, perfectly laminated to the deck and interior fiberglass surfaces. Super strong, light and impervious to delamination by water ingress. If this part of the deck had one of the steel plates, the plate would be 1/4" thick  and located close to the bottom interior fiberglass.

Steel Deck Plates

Apache decks were built with backing plates embedded in the deck for deck hardware These plates are 1/4" cold rolled steel plates as are embedded into the fiberglass decks under the cleats, stanchions, etc.  My original survey showed up a few minor spots of bulging below the deck and two spots in the forepeak where the deck had cracked open below the bow pulpit bases and showed rust spots. During spring '96, I decided to have a closer look. I climbed into the anchor locker, and began to open up the places at the bow pulpit with a wood chisel. The plates went across the deck from side of the bow pulpit base to the other.  The plates were very rusty with chunks  falling off. I eventually found the sides of the plates and chiseled the fiberglass away until the forward plate was completely exposed. With the longer aft one, I cut back the fiberglass until clean metal (about 10"). Then cut off the rusted part with a Makita 4" grinder with a cut-off wheel.

I considered the options of what to replace the plate with.  Either fiberglass, foam, 1/4" G10, or stainless steel would work fine. I had two new plates fabricated in stainless using the old ones as patterns. Then I reglassed them in: mat between the plates and the deck, one layer of mat and one of cloth to cover the plates. Doing fiberglassing upside down is normally a messy proposition, but this job went smoothly. I repainted below the deck where the work was done and the result is strong and attractive. If I had it to do again, I would use foam instead of stainless and then mount an aluminum backing plate below the deck.

I used SS screws and nuts in the stanchion holes to hold up the plates and hold it all together while the fiberglass hardened. The screws were a bear to remove, and during removal they were ruined. Next time I'll use cheaper steel hex head screws and wax them first to make release easier. Or maybe nylon screws which can more easily be drilled out. Better still, support the plate from below by wedging thin sticks  to other parts of the boat. Also, next time I'll use a magnet first to locate the edges of the plates and then carefully remove the fiberglass below so I can re-use the fiberglass piece. My work was in the not-so-visible anchor locker.

I found that most major deck fittings (stanchion bases, cleats and inboard jib track) also use steel plates. Two other places are delaminated. The rest (about 20 of them ) are OK for now. The moral of this story is that sealing all deck hardware is really important as a preventative measure on the Apache.

This piece of the interior below deck fiberglass surface was removed to in order to remove a steel deck plate. It was bulged and cracked where the steel plate had rusted and expanded.

On the inside of the same piece, rust stain from the steel deck plate is evident. Any bonding had long since given way and the fiberglass came right off after cutting the perimeter.

Replacement of the Deck Plate Near the Starboard Shroud (Spring '07)

n the 13 years I have owned Second Sojourn there developed a deck bulge at the stanchion base near the starboard upper shroud. The deck was bulged up about  3/16" and cracked below decks. I verified with a magnet that one of the steel backing plates was causing the bulge. I wanted to fix it when I had the time, but the time was not to be. Also this plate is partially obscured below deck by the upper shroud chainplate mount, a thick fiberglass right-angle bracket that ties the hull to the deck for the chainplate support. A critical area since the upper chainplates hold up the mast so I was a bit nervous about possibly weakening the deck in that area.

These steel plates are one weakness of the Chris Craft design. They are carbon steel embedded in the deck as backing plates for deck hardware such as stanchion bases, cleats and the inboard genoa track. If they get wet due to leaks, they can rust and if they rust enough, they can either bulge the upper or lower part of the deck, crack the fiberglass, and weep rust. When I bought Second Sojourn I replaced the two large plates forward that support the bow pulpit. It was a pretty big job but the repair has held up fine.

My posting earlier this year on the Chris Craft Sailboat Yahoo! web group  to request advice returned George Wigfall's response. George did an extensive refit to his Apache were he actually removed all the plates from his deck from above. From above the work to remove the plate and replace it is a bit easier, but then the deck must be finished to match, and this is a pretty big job. When removing a plate from below you work over your head which is difficult. But the fiberglass skin below is thin and easily removable, (although not necessarily accessible) and the repair is structural only, no fiberglass finishing required. Most below-deck places are pretty well hidden.

'07 was the spring to replace my problem plate. I chose to replace it from below, knowing that I would have to cut it into pieces to get it out. When steel rusts, it expands in volume. Since the steel plate is completely enclosed, it expands the deck. That was causing the bulge. The plate had to go. It was bulging up the deck above and bulging and cracking he fiberglass layer below a bit  It was partially obscured below deck by the original chainplate support. After considering both approaches,  I chose to remove it from below. The steel plates are all buried 1/2" below the deck surface but are only 1/8" above the thin lower layer of fiberglass.  Years ago I replaced the two bow pulpit backing plates from below using a similar technique. I had reasonable access from below while sitting in the hanging locker, and the mess would be somewhat contained by the lockers. Also I wasn't looking forward to repairing all that deck top fiberglass with the lines cut in. I know George did all his plates this way and was happy with it, but my finish fiberglass technique is not so great. From below the repair would be well hidden in the ceiling of the locker. I worked while sitting in the hanging locker and the job took several hours spread out over a few days.

Step 1 was to locate the edges of the plate with a magnet and mark it with a pencil. The plates are each a bit unique but generally they are about 18" x 6" and go all the way from the outboard bulwark to near the cabin top. I removed a 6" x 6" piece of glass from below to access the center of the plate and the 3" strip from between the 2 chainplate mounts. I made 2 cuts in the steel plate to remove the center part of it. The inboard part of it was still  intact and not rusty at all, and to remove it I would have had to remove the shelf above the hanging locker. So I left that part in place. By removing the center part  and leaving 1" protruding as a way to grab onto it, was able to get the outboard 6" plate removed by sliding it inboard with some effort.

Step 2 was to unbolt the stanchion base and loosen the upper shroud turnbuckle to remove any compression of the deck. These bolts were so stuck with a 5200-like caulk that I had to drill off 3 bolt heads and pound them down with a hammer and a sacrificial phillips screwdriver. I was worried that some of this tough goo might be gluing the plate in place so I drilled the 1/4" bolt holes oversize to 5/16", with a plan to go larger if needed.

Step 3 was to loosen the outboard end of the plate which was stuck in there good. This took 2 hours of hammering, prying the deck up, prying and wiggling the plate down and the chainplate mount down. The hammering freed up some of the loose rust pieces. I drilled  a couple of additional 5/16" holes in the plate from below to allow a large modified screwdriver to pry the plate sideways. Eventually it moved 1/4". In another hour it moved 1" and then finally came out. I cleaned out the slot with a thin wire brush, and then with sandpaper glued to a stick of plywood.

Step 4 was to refill the void. I used marine structural foam, the modern equivalent of what the original deck was made of. I made a few 3/8" thick pieces and replaced the plate with a three piece puzzle of foam. They were put in place with West epoxy thickened with high density filler. I then injected a bunch more thickened epoxy in the old stanchion holes to fill any voids on the top of the foam. The few cracks around the foam below were filled with heavily thickened epoxy just so the glass would lay flat.

Step 5 was to compress the deck a bit in order to pull the bulge down and to fill any voids in my epoxy repair. I placed two 1/4" flat head bolts right through the deck and the chainplate support to pull the construction together and  squeeze down the still bulging deck. I countersunk the 2 bolts into the deck, epoxied over the heads in the deck, and plan to leave them there forever. They were tightened down until most of the bulge was gone and the epoxy began to squeeze out.

Step 6 was to glass over the bottom. I use a great  material called "biaxial stitch mat" consisting of two 45 degree biaxial glass layers stitched to a thin layer of mat. This stuff is my fiberglassing secret weapon. It is exceedingly strong and one layer is 1/16" thick finished. It only took one layer to cover the foam. Just 5 layers of this stuff were used to glass in the engine mounts for my 40HP Yanmar. I have a roll of it left over from the engine job if anyone needs some pieces.

Step 7 was to re-mount the stanchion about 4" forward of the original spot. The two forward holes would go right through the forward shroud chainplate mount (super strong) with just big washers, and the 2 aft holes would go through the new foam construction with a 1/4" aluminum 1.5" x 3 1/2" backing plate.

Step 8 is to finish below by painting and fair and refinish the top deck. This step has not been completed yet.

Cutting the steel plate in two places from below, with an abrasive cut-off discs is no fun. I used full protection of my face, hands, head, hearing, etc. The trusty Makita 4" grinder, a handful of abrasive discs and perseverance finally won.

I realized when I was banging away below with a hammer how solid and substantial the deck and chainplate areas are on that part of the boat. I'm still not 100% happy with deck-mounted upper shroud chainplates, but I now understand why they have held up (the mast) on so any boats for all these years. George replaced his upper chainplates with long vertical plates glassed to the hull. I agree with this approach, but the existing ones seem to work fine.  Someday....

Here is the repair from the top. The stanchion has been moved forward from the shroud and the original holes plugged. Note the other two holes for the 1/4" flat head bolts I embedded in the deck to hold the repair together and to reduce the bulge. The bulge is 90% gone.

This is the repair from below, before painting. Note the two 1/4" bolts embedded in the deck (with large washers) and the new 1/4" aluminum backing plate for two of the stanchion bolts. The other 2 stanchion bolts go through the very strong chainplate mount and so only needed washers.

I hope the port side deck plate doesn't give me the same trouble. Its accessibility is worse due to the cabinets behind the head. I would probably replace the port side one from above.

Many thanks to George for his help and inspiration.

Apache 37 Keel

The Apache keel is an interesting design: The hull has traditional lines that bring to mind a full keel, but the keel is actually an aggressive (for 1968) bulbed, iron fin keel. There are not many boats made like this.  This reduces wetted surface versus a full keel and as a result, the steering is more responsive than a full keel boat and the light air performance is outstanding.

The keel has a wide flange at the top and 14 large flat head bolts are used to attach it to the hull. This keel mounting is extremely strong. One of the 3/4" x 4" flat head bolts has the strength to support the 6500# keel. This design could only be done in iron: a lead flange would not have adequate strength in its flange.  The joint between the keel and hull must be faired with an elastic material. When I bought her, the caulking was loose in places.  I removed the caulk, cleaned the groove out and applied epoxy primer (barrier coat). I applied a hard filler, but this was a bad idea. Within a year it had cracked. So learning my lesson the hard way,  I ground out the hard filler (Makita grinder)  and applied a softer caulking, Life Caulk, which worked very well.

Most iron keels are prone to small rust spots in the spring. Each spring I would grind the area around the spot and apply a couple coats of Interlux 2000 barrier coat to the spots. I eventually ground the entire keel down and barrier coated it  with 5 coats. Much better.