Comp 6.
This set of shots shows a number of Specter 150/200 Ventura desalinator modules fitted with
hose specific plywood mounting cases. They are meant to help protect vulnerable units from damage
and also hold connecting hoses in a way that won't allow kinking or pulling, with best access to hose clamps - & filter changing.
Left side, un-assembled. Right side, ready to be mounted vertically on bulkheads in & around the forward dinette seat locker.
Imco the construction style of these cases generates from the facinating & unfamiliar STITCH&GLUE method of kyack and tender building (Ken Littledyke INV, see wikipedia).....
Where thin high-grade plywood is assembled by bending precut shapes and binding their edges by butting them together and holding them with wire thru adjacent holes.
The resulting wire stitched compound shape is epoxy-gel glued at a number of strategic places to hold the intended shape. Then the stitches are removed, the weld points cleaned up, and the full length of the butted seams filled and filleted with thickened epoxy. The filleting is deliberately kept smooth and fair. Cure until firm. Then the whole surface of BOTH SIDES of the 3D shape gets covered with light weight fabric, usually 4 - 6oz fiberglass. This technical quantum leap makes very strong monoque structure for its weight. [an experiment with the method at: TENDER by EBB - Or The WayWide (sic) in Technical forum]
DESCRIPTION
Top two photos. End of system diverter valve: with many choices for in/out tube connect. This simple (no 'off' position) p.propylene valve is the sampling tap AND the product water on-route from desalinator to storage. Brine waste is led directly overboard thru another fitting, usually to a valve at a thruhull.
Next object: primary strainer for incoming seawater. First module after the saltwater seacock.
(Center bottom: thru hose fitting for mast electrics (nothing to do with desalinator) with the fairing plates Aluthaned, ready to install.)
Middle: 5 and 20 micron filters, at the moment without a cover.
Little black pig is the accumulator which provides steady pressure from the (black) pump shown
in the last picture: Inlet seawater pump module. Fresh water charcoal filter for system flushing - service valve on the center white metal frame - and black feed pump to micron filters that deliver clean salt water to the Clark Pump Intensifier, ie the reverse osmosis membrane that makes the drinking water. (not shown, as this much larger mod is installed on its own dedicated shelf in the V-berth.) Where the hell to put all this stuff?
Boxes are strategically cap-screwed inside the forward starboard seat locker walls - with nuts on the inside. Modules are similarly mounted to their case, allowing removal of both at once or just the module. Pressure hose is reinforced clear vinyl - stiff and not very friendly.
Inlet pump module needs air circulation & access - so it's installed athwartship outside the forward seat locker in the dinette kick space. Sliced off corner fits against the hull.
3 SECRETS
These little boxes are all right angled - require no stitching and no fasteners. Pieces are propped together with blocks of lumber or anything handy - for initial gluing.. The idea is to get a predetermined 3D shape by buttering edges with small amounts of thickened goop, letting it set. When you stick together 2-3-4 sided open units, you can easily pull generous (approx 1/2"R) fillets on all inside corners - using a 2oz plastic syringe to apply controlled worms of thickened epoxy. The COVE FILLET is the first secret of this construct. The glue is 100% solids, no-blush, 2:1 laminating epoxy, mixed with fumed-silica. Slow hardener. (TAP Plastics, Premium Laminating Epoxy)
The second secret: After full or partial fillet cure, lay in a SINGLE LAYER OF FIBERGLASS coverng the whole inside surface to tie flats and verticals together. Use a pliable (green) spreader to keep the amount of liquid lean and press the fabric onto the plywood. Butt join fabric pieces on flats when you have to. Arrange cloth at 45 degrees (diagonally) to get it to turn corners. Isn't easy but sure is a lot of fun. Cure.
[Difficult to explain how to apply cloth. Cut to very loose fit - arrange it in dry - then stick it on - wet it out - by dabbing with loaded brush. Try not to pull weave of fabric too much out of shape while teasing it into corners when going from horizontal to vertical. Get frisky with Fiskars cutting out 'V' darts in corners. Cut wet fabric for accuracy. Gently pull it off the wood, cut out the offender, paste it back in place.
OR make a single cut into the corner - down the middle of too much fabric - and just lap it over on itself, covering over the cove fillets.
Light weight fabric has very little thickness (1/32") when wet, and lap joins pretty much disappear... finessing cut edges by gently poking with the brush-tip. Make sure fabric is squeegied tight to the surface of the ply, and itself. Don't forget to wipe the epoxy off your zizzers! Isopropyl alcohol 91% RiteAid.]
After rounding corners and edges, etc. cover the whole outside in a single layer of cloth & epoxy. Let the fabric flop over edges, don't attempt to turn the fabric trying to glue it onto a narrow edge. Run cloth over holes - cut fabric out after set and round holes and edges smooth. Slice off cloth overhangs when dry to touch with utility knife.
Let pieces cure. Detail sand and shape until satisfied. Don't worry about edges not covered with fabric, won't matter. Fill the weave with a second coat of epoxy gel if desired. Leave no ridges. At this time touch-up/seal raw edges with liquid epoxy. Cure. final light sanding overall and paint.
What you see in fotos is one coat of Aluthane - no primer. Because the cases are quite detailed, they look like they might be cast aluminum metal!
The method: covering with glass inside & out over reinforced corners makes an amazing structure, stiffening thin ply, making a seamless cohesive object stronger than any traditional mehod, imco!
The third secret is 6mm or 1/4" MERANTI BS1088 HYDROTECH. Make sure your maranti has the British Standard stamp.
[ I think this technique, including form-fitting to hull curves, using the materials described here, perhaps a size up of plywood and fabric, (if it hasn't been done already!) can be used to fit out a 23-30ft cruising sailboat. Wish I'd done it. Many other uses aboard: light weight bins - lockers - panels - shelves - Dorades - containers of every sort (including lids) can be prefab, primed & painted. If conceived modularly, interior furniture can be installed with fasteners, rather than permanently glued. Nearly everything can be designed removable. A racer day sailor can be transformed into a tricked out weekend camper. And back again.]
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