It fits.....

This is where the port side centerboard case will live out it's useful life.  I've positioned it in place temporarily and will remove it so that I can install the other support webs.  The case is offset nicely and it leaves plenty of walk way floor space inside the hulls. Notice, however, I have not yet installed the floor supports so you are looking at the curved bilge of the hulls.  Also you will notice that the case fit is not yet complete because the top portion of the case needs to lay flush with the top surface of the side web.   Regardless, I will sleep better tonight knowing that it is going to be possible for me to actually build this cat with centerboards........As Ian Farrier says : It's a lot more work. He's right but I still want to be able to run this ship over unseen sand bars without having to worry about smashing a dagger board or ripping an unwanted slot in a hull. 

Stressful sawing

Cutting a gaping hole in the bottom of the port side hull was a stressful thing to do.  After days and days of stretching string lines, making measurements, swinging plumb bobs, wielding levels, shining lasers and pretty much convincing myself that I knew where to cut my centerboard case hole, I went ahead and cut it......will the case fit...... or will I have to build a new boat?  The wood piece is a representation of the cross section of the centerboard case and here, I am using it to check the fit of the case before I man handle it in place.

Marking the location for the port side centerboard case install

Although this is not the most elegant photograph of the interior of the port side hull, it shows a number of sharpy pen marks that I have made to convince myself that I know what I am doing. ( measure five times, mark three times and cut once )

You can also see the multi layer unidirectional upright web along the left side of the door opening. This, along with several more reinforcing webs will provide ample bonding points to distribute the forces that will be generated by the centerboards.

Port side centerboard case trimming

The forward end of the centerboard case nests into the inner hulls forward of the mast bulkhead.  The lower edges of the case protrude through a slot cut in the boat and will be trimmed to match the curves of the hull.


forward end of port side centerboad case

Here's a close up of the forward end of the centerboard case awaiting an end cap of glass and epoxy.

Port side centerboard case

Here is the port side centerboard case resting on top of the port side master cabin top.  This was as good enough place as any to prepare the edges of the box for external glassing.


reason enough.....

Here are 16 reasons to build a cruising catamaran........nice compared to 9 degrees outside the shop.  Tonight, it's colder here in Hood River, OR than it is in Anchorage Alaska.  The extension cord is running to a small heater inside the bridge deck cabin keeping it a comfortable 75 deg. inside the boat. Maybe I should think about naming her "Thermos"


clamping the centerboard case sides together

With a record cold front on it's way to the Pacific Northwest, what is beginning to become the port side centerboard case is nice and warm inside the main bridge deck cabin. Notice  that the little 750W heater has kicked itself off and it is not having to work too hard to keep things tropical inside.  Outside, the first winters snow is beginning to fall on the metal roof of the shop. 

joining the centerboard cases sides

  To control the precise distance between the centerboard case sides, I've wrapped a 4 x 6 inch wood with tape so that I can use this as an internal spacer.  Next, the plan will be to lay glass and epoxy over the  spacer, add foam along the ends and clamp the centerboard sides in place. Once the epoxy cures. I'll remover the spacer.


Setting up the boards for some hand shaping

Here I am preparing to hand shape one of the centerboards. The Oregon sun was low and strong on this 2nd of December and in honor of such a beautiful day, I decided to set things up outside.

You'll notice the recessed spar which will be covered with 15 layers of 12 inch wide uni glass in between  two layers of 24 oz triaxial glass. Since the final external dimensions will be critical,  it will take a bit of skill to shape these blanks while taking into account the required schedule of glass. Not only will I need to achieve the perfect foil section, I'll need to be able to do that by anticipating the thicknesses of individual layers of glass that will be layed in various places throughout the board.  for example; the leading edge of this board will be covered with additional layers of glass so I'll need to create a recessed leading edge so that it can be built up and fared to the correct external final shape.....it's sort of like trying to work backwards in time.


checking the fit...

OK, since I had to cut the spar out of my blank, shape it, impregnate and glass it with epoxy then bond it back in, Here's the board blank with the spar core pressed into it's home again. Next step will be to bond it back in place using a good thick mixture of micro / cabosil and epoxy.

Tomorrow I'll have a go at these blanks with a power planer and shape them like two big long boards. That will make for a good day.......maybe I'll add a fin box and take one to the Oregon coast for a surf session. or....maybe mount a mast base and windsurf it here in the Columbia Gorge.....or give it to by buddy Cory to do some free style strapless kite boarding with it.......

de bagging the centerboard spars

Here's an interesting way to open a vac. bag.....

Fitting the centerboard spars

Originally, I created my centerboard blanks with the high density cores  (mahogany spars)  all in one. but I decided to laminate, shape then wrap the spar cores individually with glass, then insert them into my centerboard blanks before the final shaping.   Fortunately, I was able to utilize a good portion of my excess foam "cut offs" to create the centerboard blanks by cutting the smaller  foam  pieces into strips and vac bagging them all together.  Notice the board blank on the left is being fitted with the spar.  


a simple post cure oven

so here's a quick post cure oven that I put together to cure my centerboard cores. tomorrow I'll pop them out of the bag and you'll be able to see what this is all about. I placed both spars inside this foam box and used small blocks of styrofoam to close in the edges between two thick foil covered foam sheets. Notice the heater in place as well as the vacuum pump sucking away.

Centerboard spar cores

After laminating, planing, shaping and tapering the centerboard spars, I am preparing to glass them and insert them back into the centerboard blanks.  In this case, I chose to use a light weight mahogany core material as my "high density" spar core.  Once these spars are embedded into the centerboards and laminated with 15 layers of 12 oz unidirectional glass,  these spars will become the primary structural elements in the centerboards.  Here, I am simply pre fitting my glass in preparation of vac bagging the glass onto the cores.  In this case, I used 3M 77 spray adhesive to keep my glass in place then I mixed a whopping amount of epoxy and rolled it on thick.  I then wrapped the spars with peel ply and vac bagged them to insure that I would get good saturation and bond between the wood and glass.  If I do this right, the wood will never know it is part of boat.  ( Being fully encased in glass and epoxy,  hopefully this wood core spar  will never see one molecule of H20 as long as I sail ) 


F-44SC Catamaran: mast base core

F-44SC Catamaran: mast base core

mast base core

Here's the mast base core.  This chunk will be fully encapsulated with epoxy and multiple layers of glass. I elected to laminate this piece from White Oak.  White Oak is known for it's durability and resistance to water.  ( White Oaks have cellular structures called tyloses. Tyloses give the wood a closed cellular structure, which does not allow water to pass.) further knowledge on White Oak: http://en.wikipedia.org/wiki/Quercus_alba

To further reduce ANY possibility of water intrusion,  all fastener penetrations will first be drilled out oversize with a large paddle bit then the void will be filled with solid epoxy, micro,  aero fill so that any fasteners will have no contact with  the wood.


hull to bridgedeck join detail

Since there are 10 layers of unidirectional glass forming the "flanges" capping each bulkhead, the join areas get 5 layers on the inside and then five layers on the outside.
This outside lamination requires that the foam be removed so that a total of ten layers of glass can form a continuous load path between the bulkhead joins.

cockpit storage

The aft bulkhead now includes a couple of storage spaces. I may eventually install hatch covers here but for now, I think I'll keep them open so I'll have a place to put things that may need to be handy at a moments notice........like maybe a large sawed off mossburg 500 pump action shotgun to discourage modern day pirates......or maybe packs of Marlboro cigarettes to make friends with them......or maybe a copy of "Bennet Carls vest pocket book of jokes for all occasions" to ease any possible conflicts.

What did they do before the days of peel ply?


forward bulkhead

In order to install the cabin top and foredeck, I needed to finish taping the forward bulkhead in place.  Unlike the mast, cabin and aft bulkheads that receive 10 layers of uni on either side, the inner bridge deck portion under the forward bulkhead receives two 8 inch wide lengths of uni directional glass with their ends lapping out onto the forward bulkhead. In this photo, you can also see the "optional" foam strip where the mast support web will be installed.  I chose to use these foam strips along all critical hull to bulkhead joints because they provide a wider base that helps distribute loads more uniformly.


rounding off the corners

The inner corners of the cockpit coaming are formed by shaping foam wedges and bonding them in place. This 8 inch radius corner will be viewed as part of the aft starboard cabin ceiling.

In this instance, I've used polyurethane glue, a few small sheet rock screws and a bit of packing tape to hold the wedges in position while the glue cures. The corners will then be sanded smooth prior to glassing the decks.

stern view

The bridge deck "transom" is now in place. This panel was vac bagged on one side with 24 oz. triaxial glass leaving the exterior foam exposed so that it can be shaped and glassed later when doing the decks. This will allow the exterior aft bridge deck portion to be glassed in one continuous lamination.

bonding the bridgedeck "transom"

Here's an inside look at the bond confirming a good squeeze out of the bonding mixture. Note the temporary screws used to pull the pre molded flanges into the back side of the panel. Obviously if I had skinny 8 ft long double jointed arms I could have taped this panel in place without resorting to all this complexity.

pre molded flanges

Here are the resulting molded flanges to which
i will bond the bridge deck "transom" panel.  Next step will be to scribe the panel, cut and fit it,  swipe a mixture of epoxy thickened with cabosil all over the flanges then bond the piece in place.


closing in the "I" beam

Here's a close up of the aft bulkhead with the two temporary foam pieces that will be used to create internal flanges.  In this case, I've used packing tape over some scrap foam so that I can then form the flanges by laying glass "tape"on the back side of this "packing tape" covered foam.

The Aft Bulkhead

The aft bulkhead get's built up as a major structural member of this ship. It is essentially an "I" beam with the shear web being the bulkhead itself and the flanges being made up of the deck and lower bridge deck sections;  both of which are sheathed with ten layers of uni directional glass. Once this "I" beam is in place, it then gets boxed in from the front by the aft portion of the cockpit and then the aft section of the boat. Since it is not possible to tape the seams of these sections from the inside, tape flanges are being formed to allow these pieces to be bonded onto the lips of flanges.  In the photograph, you can see both top and bottom horizontal foam pieces that are covered with clear packing tape as a release. I'll tape these removable flange pieces in place then once cured, I'll remove the temporary foam pieces to reveal the glass flanges.  Then, I'll rough sand the flanges, trim the bridge deck "transom" piece and bond it in place.....then I'll perform the same dance when installing the aft cockpit piece.


A view from the port side hull

Upper right is a record breaking 3/4 faired gravity bike along with my swing and bubble pop corn popper. 

uni directional glass for hull to cockpit join

It's handy to pre cut all of your glass before you begin any layup. Here are the four sets of 5 layers that will be used on the aft bulkhead joint. Not only does preparing the glass before hand prevent me from getting epoxy all over my scissors, it allows me to be more aware of the resin cure rate.

Aft bulkhead to port side hull join

Here I am preparing to apply uni directional glass along the under side of the aft deck and bulkhead. Since the join area along the under side of the deck incorporates ten layers of Uni glass, in order to insure uniform strength,  five layers are applied along the lower surface then the foam will be removed along the top deck surface so that five additional layers will sandwich the join area.


joining the bridgedeck

Once in place, scribed, trimmed and fitted, I used 1/4 in. lag bolts and squares of 3/4 in plywood to insure a good smooth join line.  After that, I ran strips of duct tape between the blocks then from the top, I filled the gaps with a mixture of epoxy and cabosil. ( the tape keeps the goo in place) After this cures, I can unbolt my blocks and fill the areas under the plywood squares in the same way. 

ladders, boards, straps and chain hoists

Lifting the 24 ft. section of the bridge deck floor single handed with one arm epoxied behind my back.....took some thinking.  I was able to use two chain hoists slung from the rafters fore and aft with a strap running down the length of a ladder while supporting the floppy forward section with a wide board and another strap.


4 parts in one

 Using my rubber pond liner vac bag table, I'm able to produce multiple parts at the same time while using just a top vac membrane.

vac bagging again....

Time to create a few more parts....here are the cockpit sides and the bow beam support bulkheads being prepped for vac bagging.

bow beam in place

Since I didn't like the idea of having to insert one end in and then cut a hole in the deck of the other hull, I elected to spread both hulls out enough to insert the bow beam in each hole that was cut in the high density insert.  I then brought the hulls back in line.

hoisting the bow beam

chain hoists come in handy when it's just one person.

inspecting the fore stay

Here I am inspecting the fore stay attachment thimbles that support a stainless steel bar all wrapped in place with unidirectional carbon.



"So who can resist black kittens sitting on rolls of unidirectional carbon?"

2 inch strips...

Since my carbon uni came in a 2 ft. wide roll, I used a couple of pieces of scrap foam and a blade from a utility knife to create a guide tool that allowed me to cut my carbon down into 2 in. strips that will be used to create the bow brace.

adjustable spreader

Here's the brace support hardware that will become the apex of the spreader. I created a mold and cast this piece using epoxy and microballons.  Since I couldn't figure out a way to lay the 8 layers of unidirectional glass under this piece, I made a profile mold that should mirror the flow of the carbon over this piece, then I can place straight timber formers under the edges so that I can lay in the 20 layers of 2 in. wide carbon spreader material.

Bonded in place

The center section of the bow beam is comprised of multi layers of glass with the primary feature being 14 layers of unidirectional carbon wrapped over the two stainless forestay thimbles.

figuring out how it all goes together....

So here I am test fitting all my parts in preparation for assembly.  They say that building a large catamaran can keep you young.

forstay components

Per fabricated parts book, here's a pile of 316 stainless that will be used to create the forestay anchor point and seagull striker.  A local fabrication show " Versatile Supply" http://www.vsisurplus.com/
did a masterful job. It nice to have friends with a CNC water jet, mill and lathe.


While I wait for my stainless steel forestay thimbles......



beware seagulls

Here's the roughed out core foam for the "seagull striker"

bow beam end

Not so pretty..... but here's a bunch of duct tape being used to pull peel ply snug against the end of the bow beam. the bow beam ends are closed off by bonding the 3/16 in glass gussets in place by covering over with two layers of tri axial glass and epoxy. Peel ply helps to create a nice neat finish that does not require additional sanding effort.

bow pole hole

Looking in through the bow pole hole you can see one of the 3/8 inch bow pole gussets that has been installed and glassed in with 2 in tape.

bow beam gussets

seen here are the internal bow beam gussets. I created these by vac bagging multiple layers of glass to create the four 3/16 thick gussets and two 3/8 inch gussets.

bow beam

As Ian Farrier suggests, it's best not to skip around the plans book. In my case, just when I'd rather be inserting the bow beams into the bows and getting on with bonding this boat together, I realized I needed to completely finish my bow beam ( including the carbon seagull striker )

Seen here is my shop monkey reminding me to follow the plans as I should.


fitting the center bridge deck stringer

Here's another shot from above. This will eventually be a shot from "below" as this is the center stringer that runs lengthwise under the center cabin along the bottom of the boat .

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center bridge deck stringer

Here's inspector Tang perched on the center bridge deck stringer. I've bonded 10 guide tubes along the underside of the bridge deck floor so that I can eventually run lines under the cabin and back up into the cockpit. I marked the locations of my tubes so that I will know where to cut into the floor section from above and mount the 90 deg. pulley blocks that will direct the lines into and out of the tubes.

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