Hey Anthony,

Not sure what "skipping" screws means, but the screws are there for the shear loads experienced while under sail.  There are no tensile forces to pull the screws through the 6mm bottom.  With that being said, feel free to reinforce as you see fit. You can also chamfer the edges of your backer plate.

Anthony,

I haven't used screws in any mast step I've built and they're still working fine. Here's the mast step for my schooner, as an example. It's stood up to winds strong enough to knock the boat over onto its side. All that's holding it together and to the boat is epoxy/woodflour glue.

Have fun,

Laszlo

   I'm also building a Passagemaker take-apart, with the lug rig.  I'm a bit worried about the structural support for the mast, given that most of the structure supporting the mast is cut away when we separate the hulls.  The forward mast step (under the forward seat) is no longer supporting the mast, and most of the horizontal shear support is gone when we cut the forward seat in half. 

All that's left is the thin bulkhead and an inch or so of horizontal seat.  Heck, even the uppper doubler gets cut in half. 

Can anyone vouch for the rigidity of the mast in a PassageMaker take-apart with the lug rig option, using the "stock" mast step and instructions?

That design has been out for many years and there has yet to be problem reported here on the forum. The builders are not shy, If there was any kind of issue, it'd be here.

Laszlo

Keep in mind that the loads on the mast step are almost entirely athwartship, meaning it's pushing against the sides of the boat along the plywood bulkhead.  With the take apart version, there are two bulkheads that get sandwiched together so there's even more support.  Imagine putting a piece of plywood on the ground and pushing down on the edge with all of your bodyweight.

With that being said, I believe the unstayed lug rig is a newer evolution of the gunter sloop, which was stayed, so takes away some of the loads on the mast step.  However, there are literally hundreds of people that have built this particular boat and nowhere on this forum or the defunct PMDBuilders.net forum has there ever been a mention of this type of failure.

The one failure that I will mention here since it's tangentially related are the knees on the aft transom.  A lot of people put the single knee in the center of the aft thwart/transom corner and noticed some failures.  The popular fix/ounce of prevention has been to make two knees and space them apart so the outboard mounting bracket fits between them.  

   So would outting screws up thru the hull be needed?

Laszlo,  did you put any addtional support on the hulllike additional layers of fiberglass?

I am committing this week to attached the mast support and go onto the next phase....

The cutting of the boat......

I used no additional supports or reinforcement. The mast steps are bedded in epoxy/woodflour putty. They are attached to the bottom and a bulkhead, each. There's a also a mast partner on the deck for each mast.

Laszlo

  Mu Passagemaker Lug Rig mast step blew out yesterday. Trying now to figure out a repair plan.

  Ouch! You've got a bit to repair, but it doesn't look too bad.

Do you know what caused it to break like that? Were you sailing when it happened? If so, what tack and what wind speed? Or did something else cause the break? I'm quite curious.

���It's kind of hard to tell but it looks like the mast step might have been glue starved. I'd expect the epoxy to hold until the wood ripped. The partner (the upper hole) would have ripped out second, after the butt came loose. To fix the partner, if think in terms of cutting out the ripped stuff to sister in a new bit of plywood, and back it with an overlapped piece under the seat if possible.

I'm with Mummichog. It look glue-starved. Also, I don't see any signs of thick fillets where the pieces of the mast step broke apart.

To avoid this in the future, paint both sides of a joint with epoxy before adding the putty, bed the side supports in epoxy/woodflour putty, use the excess putty (adding more if you have to) to form nice fat fillets along the joints.

The unthickened epoxy will prevent the raw wood grain from sucking all the epoxy out of the joint. The putty bed will evenly distribute the forces across the whole joint, preventing stress concentrators. The fillets will evenly transfer the lateral forces and reinforce against them. This kind of t-joint is the place on your boat where you actually want fat fillets.

The other thing that I see is where your mast has been grinding against the bottm of the boat. I'd put a couple of layers of glass there if that was my boat.

Good luck,

Laszlo

���I worried that i was making fillets too thick but in this case, more is better. I too have the forward bottom corner of my mast rubbing hard. It is already rounded off but I guess not enough. This winter I'll take a file to it and bevel it more.

Wow, that's one of the more catastrophic failures I've seen on this forum in years.  Good news is that there's a way to fix it so that no one will ever know but you that it ever happened.

If the boo boo is 6" wide, you'll need to dish out a repair patch scarf that's 8:1 the thickness of the plywood.  So, if you're using 2-1/4" layers that equals 1/2", then you'll need to carve out a patch that's 4" wider on all sides (1/2" x 8 = 4"), which creates the female mate.  Then create the matching male patch that's 14" wide (6" + 4" + 4" = 14") that fits perfectly into your crater.  

Once that's done, mix up a good batch of silica-thickened epoxy and butter both sides, using plastic wrap on everything to keep the wrong thinigs from sticking together and cauls/clamping pads to press the patch into place.

Once cured, sand everything flush and make a 1/4" cover plate with eased edges to go over the whole mess which will just make it look like you beefed it up on purpose to begin with.

   Wow - thanks folks for all the advice - the back story is that my son was out in windy conditions - made a turn to the starboard tack and the mast step blew out -- he had to row home. I've got some spare okoume plywood and I'm working with CLC to get some new doublers. I don't think the repair will be too involved. The lower portion of the mast step held and the screws and fillets are still in place, but if I'm reading the comments right the new fillets must be big and  fat to distribute the load -?

Some add'l pix-