Subject: Jet Squirt Update
Date: Mon, 1 Mar 2004
Barry,
Here's an update on my Squirt project. I've also attached a drawing I
made for the structural changes that I will need to make for the jet drive
installation. If you think it's appropriate, feel free to post this in the
"customer photos" section. If you have any comments on the structure
I'd sure like to hear about them. Note that I've eliminated the keel
and inboard battens aft of frame number 1 - this allows me to mount the jet
drive an inch lower in the boat than I could otherwise. Also, I was thinking
about using 3/8" plywood for the aft bottom section, and installing both
sides in one piece aft of Frame #1. I plan to block all the corners (i.e. no
screws into end grain) buy have chosen not to do that for simplicity in the
drawing.
UPDATE:
March 1 - I haven't done much woodworking in the last couple of months, but
a lot of design engineering! Turns out putting a jet drive in a Squirt is a
fairly complex proposition. In December, I cut out and assembled the stem,
breasthook, and both frames. The transom is cut out but not assembled due to
uncertainties in what needed to be done for the jet drive modifications.
I found and purchased a well-worn but good running jet ski (a 1982 550
Kawasaki) off e-Bay. Then I completely disassembled the jet ski to get all the
"good stuff" out, and measured all the critical dimensions. I also
purchased the service manual for the ski from Kawasaki. This gave me a wealth
of good information - including things like the jet pump thrust (340 lb) that I
needed for the boat structural modifications. Unfortunately, the manual
didn't provide things like bolting patterns, these I traced onto heavy
paper, then transferred them to 1/4 plywood to act as templates.
I've spent the better part of a month thinking and doodling on how to mount
the jet assembly. The overall drive train length is 57 inches - too long to put
in the boat without lengthening it outside of the Glen-L recommended range. For
this reason I decided to mount the pump on a bracket outside the transom. This
allows me to lengthen the boat to 11'-6", and keep everything aft of
Frame #1. The primary structural modification is to eliminate both the keel and
inboard battens, aft of frame number 1. These are replaced with engine
stringers fabricated from 2x4 stock. Also, I added a half frame, that I'm
calling a "bearing bulkhead" that supports the drive shaft, and forms
the from of the jet pump suction tunnel that runs down the center of the aft
section of the boat. Here's a sketch of what it will all look like:
Just to make sure, I've decided to do a "prototype" of the
arrangement, just to make sure everything fits properly before I actually do
the frame assembly. I'll report how things go with the prototype next
month.
Best Regards,
Terry McIntyre
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