Trial fitting the beam cores

OK, now it’s starting to feel like a multihull! With the beams set up, we got our first taste today of how big the main nets are going to be – lots of room for stargazing evenings.

Big thanks to Dad for the painstaking drill press and cutting work on the 8 aluminum tangs that emerge from the beam bottoms and attach to the diagonal braces. Those braces are about 3 ft long, made from heavy 1/2″ stock. The plans allow them to be narrowed down to 2″ along most of the length. I think after all the trial fitting they’ll go to a cutting shop to remove that extra weight, but more importantly when they are narrower, I’m thinking it’s less surface area for waves to hit on the leeward side.

The second photo shows the positioning of the tangs inside the beam. The web they attach to is 12lb high density foam with six layers (each side) of 18oz bi-directional fabric, alternated 0-90 and 45-45. This is some of the beefiest fiberglass construction on the whole boat. Next week is a multi-step process of positioning the metal precisely on the web using wooden dowels, then glueing one tang at a time, drilling out the dowels and replacing with bolts, etc. etc. Many more hours of permanently hidden details :)

looks like the boat is stretching out its arms for the first time

note to other F36 beam builders:  plans call for putting the ‘wings’ on the top of this web before you glass the web in place (same as the beam-attach web in the top of the photo). Having those wings in place made it really difficult to work on the tabbing-in. This time I’m leaving them off for now, and once tabbed in the beam, will go back and add wings with the similar method Farrier wrote for attaching the full side-widening edges just before installing the beam tops.

They fit!

at least the starboard beams do anyway… tonight was drilling the holes in the ends of the beams to accept the big 1″ diameter main bolts. Plans call for bonding the bolts in place right away, but I needed to do a dry-run fit because it was worrisome about how these holes would line up exactly. It was hard in my mind because the beams are not at their final exterior dimensions yet, so you can’t just plop them in location and trace the hole. It’s careful transcription of the plans on to templates then the stock, etc. Here’s the first beam being tested in place.

The rear one fit too. They’re back down on the ground now to have the bolts permanently bonded in, and the slices on the bottoms cut for the diagonal brace upper-end tangs. After the starboards are all fitted, measured and bonded in position, we’ll take it all down and rearrange the shop to move the boat over to fit the port beams (hopefully still in June).

Main hull bracket plates for beam braces

The slices on the hull sides shown in the last post allowed the starboard forward bracket plates to be installed. These are now the anchors for diagonal braces that will attach to the bottom of the beam(s). Here they are bonded and bolted in place, but a lot of finish work to do around the edges. This pair of plates is being installed after the floor went in and the forward cabin closet built. Not ideal, as I had to cut in to prior work and will go back for touch-ups. Some of the compromises when you’re buying stock based on budget, availability and time!

Exact location of these plates is acheived thru a clever jig that bolts in place at the primary beam bolt holes, and holds the brackets for position marking before final bulkhead laminations, and then again while you do the actual bonding and bolting application. Note we’re using little aluminum tubes the same size as the real bolts to work around the brackets being so close to the boat’s cradle.