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A Perth Riviera # 3 – to November 2012

On November 3, 2012, in Inboard Powered, by Andrew

While the essence of a boat like the Riviera lies in a gloriously varnished mahogany hull and lots of shiny chrome bits, a critical element of the overall aesthetic is that big rumbling V8 sound.  And so the key parameter for the engine that I would eventually need was determined very early in the process – it had to be a big V8.  While many hours had been spent in my far off youth fixing, rebuilding and generally playing with engines, the prospect of modifying a car engine for marine use seemed to suggest an unnecessary diversion from the necessary process of boat building.  So another key parameter was set – it had to be a marine engine, ready to use.

Now they are not giving marine V8 engines away down here with PCM and Mercruiser the easily available options and looking to cost a significant percentage of the overall budget for the boat.  So it was decided to start a search for a second hand engine early in the build process so that an engine would be on hand when the moment came.  An optimistic approach I grant you.  Never the less, the process of scouring ebay and similar outlets began.

Riviera by Andrew Crocker-46Finally, a prospect turned up on ebay and I was able to procure a 2004 PCM ZR6 engine (without gearbox) for a very reasonable price.  Eventually, the engine turned up missing various parts and with a lot of pipes dangling.  So much for minimizing the distraction from boat building!  But it was allowing me to avoid fairing the frame, so this was not all bad news.

For some reason, the 2004 PCM ZR6 is annoyingly short of documentation.  While the PCM web-site and other useful resources have significant holdings of material on other PCM engines, this one seems to have slipped through the cracks.  A parts manual and operational manual were located but they left many mysteries (particularly around the engine management system) unanswered.  Never the less, parts were obtained, the various loose ends tidied up and a rolling frame constructed to allow it to be moved around and test run as needed.

A very rough wiring arrangement and instrument panel was constructed (with only an oil gauge for instrumentation on the basis that this was the most critical element), a less than robust fuel arrangement provided, and a raw cooling water system knocked up with the garden hose.   In what can only be described as a miracle, the thing started first time and ran like a dream with the full V8 rumble on display.  The only complication was having to bypass the engine management system to activate the starter motor due to some set of conditions/interlocks not being met (as yet unknown due to the aforementioned documentation issue).  Later ZR6 models reverted to a much simpler starter motor wiring – perhaps this is why.  Anyway, a job for the future and with confidence that the engine would do what was required, it was stored away for future use.

Which left fairing.  A number 7 plane was acquired and certainly made the fairing of the aft part of the hull a straightforward process.  The obsessive measuring of frame setup had meant that that section was close to fair in any event.  By far the worst process was the sheer.  It is close to the ground, requires a lot of wood to be removed at the stern section, and a mistake early in the sheer slot cutting process meant that a number of filler pieces were required to bring it to a sensible shape.  Between a small plane, rasp, Stanley Surform, and a disc sander, eventually the sheer and other elements were brought to heel and by the middle of October 2012, a faired frame (or close enough) had appeared and some pieces of ply optimistically laid to provide a sense of what was to come next.

Riviera by Andrew Crocker-48

So with a faired frame in hand, so began the process of putting on the first layer of laminations.

Riviera by Andrew Crocker-49A pile of 6 and 4 in 1/8″ plywood strips were cut from 8 x 4 sheets of marine ply.  As importantly, several thousand Raptor 1/4″ fiberglass staples and a stapler were acquired from Glen-L.  These have proven to be a wonder as they provide more than enough holding power for almost all circumstances but then sand/plane down very easily avoiding the need to remove staples.

The laminations were laid at a 30 degree angle which was about the maximum angle that would allow the 4 ft strips to reach from the keel to the chine.  Bevelling of the strips was done by hand (without a jig) and certainly contributed to a rigid first layer.

It is a slow process but the shape of the hull began to emerge as the laminates went on.  The 6 in laminations were used up until around frame number 6 at which point I switched to 4 in laminations to better handle the increasingly complex curves.

Riviera by Andrew Crocker-60The sides, particularly around the stern section, were a slower process again with a lot of cuts and a significant amount of waste.  My careful calculations of how much plywood would be required were looking increasing shaky as a mountain of strips began to be absorbed by the laiminating process.  The subsequent laminations on the underside are definitely going to need to use these scrap pieces otherwise far more wood is going to be required.

But suddenly, the sides began to take shape as well.  The transom was left long and squared off deliberately to allow me to contemplate the preferred shape when the boat was rolled over.  The barrelback has always appealed and the option was being left open to modify the stern section.  We shall see.


After a final push, the final week of October saw the first layer of laminations being completed and the hull shape finally revealed.  A slightly difficult curve eventuated at the stem end of the sides where I don’t think I captured the transition from the side flare correctly.  But a little bit of fairing of the subsequent laminations should sort that out.

Riviera by Andrew Crocker-61

Next step; rough fairing and second laminations.


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