SEDATION 4  Cabin Roofs Installation

Moving the three molded roof sections into position requires lots of brute force.  Although the strength-to-weight ratio of these composite structures is impressive, they are still heavy and cumbersome to maneuver within the confines of the assembly shed.
We decided that prepping the exposed underside areas was much easier before installation than working upside-down later, so a little sanding and filler work was performed on the as-molded part.  These surfaces will be rolled with white gel coat for a glare-free finish.
Spanning the lower saloon area, over the galley and bar area, is the shortest roof section.  It is installed first to to stiffen the side walls before placing the large pilothouse roof into position.  The aft wall also gains considerable strength once laminated to this roof.
The forward "ears",  which were formed during fabrication in the roof mold, engage slots which were CNC cut in the side walls.  The resulting intersection provides for stronger joints during lamination.  The profile of the molded overhanging "eaves" can be seen easily in this view.
Along the side decks the eaves extend 6" past the walls.  Further protection from the elements is provided outside the aft wall with a 14" overhang.  The vertically-sliding screened wing windows are, therefore, usable even in the worst weather.
Closing-up a portion of the interior is exciting.  With the roof in-place, the proportions of the galley area can be appreciated.  A "valence" which was formed during molding is visible  on the right.  These provide support for the headliner, obscure indirect lighting and drapery tracks plus add stiffness to the roof.
Over the bar area, on the starboard side, the vertical relationship of the valences to the windows and exterior eaves can be discerned.  Trim molding, that will extend 1/2" below the valences to finish-out the headliner installation, lines-up perfectly with the powder-coated aluminum window frames.  The bottom edges of the eaves line-up with the top of window's glass.  Little details like this are esthetically pleasing and easy to incorporate when everything is designed properly.  Notice the nominal 1/8" gap between the aft wall and this roof section in these photos ... not bad for two parts fabricated independently :)
Since the icemaker and refrigerator have already been fitted in this area, all that remains is installation of the padded vinyl wall covering, the formica countertops and headliner before it should look like this image from the 3D renderings.
One more picture of the aft roof before it's laminated in-place.  The strips of blue masking tape, seen throughout the construction process, indicate areas where laminations must stop.  This prevents thickness variances which could compromise smooth operation of the sliding windows.
The slanted (5°) roof over the beds was finally removed from the roof mold and moved outdoors.  Moving this huge panel required the brute force of 8 men to maneuver it from the mold room, off the loading dock and onto the padded drums in front of SEDATION 4.  After trimming, I washed the PVA mold-release off the gel-coat top surface.  The molded-in rain gutter performed as designed; it diverts water from dripping off the forward edge and routes it to either side.
Almost time for installation but, first, the bedroom porthole openings should be cut.  They are tucked way-up under the overhanging forward eave, for better rain protection, which would complicate the cutting task after roof installation.  I made a router template for the  large (7" x 17" window size) Bomar G818 portholes, using the ShopBot, for easy and precise generation of the required openings.  Unfortunately we had no profile-cut router bits that would cut through the thick 1.5" forward bulkhead so I hand-traced the contour at the proper locations and we cut the holes the "old fashioned" way.
Man-handling the roof into position would be a formidable task.  We used a fork lift instead and the job was practically effortless.
When deciding on the fore-aft position of the molded-in rain gutter, I optimized strength of the underside laminations to the forward bulkhead by locating the gutter slightly behind the bulkhead's aft face.  The roof's honeycomb core is eliminated at the gutter so multiple layers of fiberglass form a very strong area where the laminations of the upper- and lower-surface become one thick mass.  Study the picture at right and imagine a lamination, between the roof and forward bulkhead, which coincides with the center wall lamination visible beneath the gutter.  This will be a substantial joint!
Once in-place, the perfect fit of the molded roof to the ShopBot-cut main bulkhead is evident.  This view is looking aft in the master stateroom with the mast tube on the right.  The sanded area with pre-drilled holes, at the upper left, will be laminated to the molded deck panel over the stateroom and the massive 2.625" side wall beams.
The staterooms' side walls are last to be installed.  These massive 2.625" thick wedge-shaped beams span between the main and forward bulkheads while supporting both the roof and side decks.  Any variances of manufacturing and assembly tolerances, in the multitude of panels assembled thus far, are accommodated in the hand-fitting of these key pieces.  The port side beam is shown at right, just prior to installation.  Notice the slight 3/8" sag of the side deck beneath the beam's lower edge?   We wedged 2x4s under the deck to eliminate this sag, during lamination to the beam, resulting in a flat, stiff deck area that doesn't "puddle" water.
The starboard side wall is shown at right post-installation.  The side deck now fits within ±.020" along the entire 92" span with similar results at the bulkhead gaps.  A few more inside laminations, between the side wall beams and adjacent components, complete the forward roof installation.  The staterooms are now closed-in and ready for interior finish work.
My pilothouse roof is the biggest one-piece finished molded component which the boatbuilder had produced; the hull-halfs are larger fabrications which require subsequent assembly.  Washing the PVA mold-release off this 16' x 10' monster was fun.  It's shown drying in the Florida sunshine here.
We inverted it to pre-finish the underside, as with the saloon roof previously.  Rain forced us to move operations under the protection of the hull.  If the areas to be laminated get wet, the resulting bond is substantially weaker, so we took no chances.   Notice the rain showers, in this photo, as sanding progressed.
Wednesday morning, March 17th, the sunshine returned.  We flipped the massive roof again, then used a forklift to raise it above the staterooms' roof.  Leaving the forward bridgedeck panel (which will span the two hulls) off permits the forklift to reach much further into the construction area.
Notice the 16' boards (actually 177" between the pilothouse walls' inner surfaces) which assure proper geometry while the roof is positioned.  With just over 50% of the roof's length supported by the forks, the balance was precarious at best.  Some folks stood beneath it anyway :)
10 people were required to man-handle the roof into position.  Click the image at right for a video clip of the operation.
Two temporary supports are in-place to maintain the precise molded radii until the windshields and aft windows are installed.  Once the roof is laminated to all adjacent panels, the entire structure will be very rigid.