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the minimum serious cruiser

"A century ago in Fairhaven, Joshua Slocum rebuilt an old sloop called the 'Spray'. On this new vessel he became the first person to sail alone around the world."
The above lines from The Millicent Library's Joshua Slocum Centennial Page summarize a legend.

In the wake of this legend, numerous replicas have been built, the first known one in Rochester, England in 1902. Ken Slack in his excellent book In The Wake Of The Spray gives a wealth of information on SPRAY and the early replicas. The introduction of Spray plans by Bruce Robert's Designs have exploded the interest in Spray based sailboats of various sizes throughout the world, including the boats under construction the number is probably well over 1000 mark today. Bruce Roberts Spray designs are extensive, cover a wide range from 22 ft to 50 ft in wood, glass, or metal. Still, you may find SPRAY 700 unique in a lot of its features:
plan & starboard view
starboard profile interior plan sections 9 & 16
    My choise is :
    • Steel Keel
    • Radius Chine Plywood/Epoxy Hull
      (pre-molded lower chine plate and stringers)

    Why Steel Keel ?
    Although it is possible to build SPRAY700 in frameless steel, it may be considered an extreme choise for this small a boat. However, a steel keel provides all of the advantages of a steel boat and where it counts most:
    • Provides a very strong backbone with low center of gravity
    • Eliminates cast iron external ballast keel and keel bolts
      Forms a substantial part of the balast
    • Eliminates the need for a building jig
    • The engine bed is incorporated in the keel design

Hot-dip galvanizing is a treatment that I would not do without. Consequently, the keel is a two-piece design joined at section 14 for ease of handling and transportation. First step is to join together and set up the stem-keel-transom bracket assemly. keel setup
floor 9-10
Sample Floor Plate Details 3D keel assembly STEP 2
Preparing Plywood Hull Plates :

Bottom Plate, Upper Chine Plate and Sheer Plate :
Plywood panels are joined together to required dimensions by scarfing . The outline of the hull plates are best transfered to them using a computer drawn mylar pattern. Alternatively, the datum line and the vertical measuring lines have to be drawn on the plywood. Mark the distance between these lines, using a steel measuring tape streched over the length of the panel. Do not mark them individually. After all the crosspoints are marked, use a fairing batten to connect them. The positions of bulkheads, floors, stringers, ect are also transferred from the drawing to the plywood. The waterline is scribed on the outside of the hull plates. Accurately cut out the hull plates along the scribed lines remembering that the correct hull shape depends on this accuracy.
Radiused Middle Chine Plate :
This plate together with stringers along both edges is pre-molded with 4 layers of veneer laminated over a mold using diagonal lamination technique and sheated with glass-fibre roving and epoxy resin on both sides.

Fitting Bottom Plates :

Clamp the bottom plates to the floor flanges aligning the floor plate markings on plywood with respective floor plates carefully. Drill bolt holes in plywood through pre-drilled holes in the steel keel assembly. Use 8 mm tapered head bolts.

bottom plate STEP 4
Fitting Pre-Molded Middle Chine Plates :
step4      Pre-molded middle chine plate stringers are screwed and bonded to the bottom plate edge by epoxy resin.
Prepare and Fit Bulkhead Plates and Transom :

Mark out and cut the bulkhead plates B4, B10-11(starboard only), and B11 (port only-with a temporary extention), and the temporary bulkhed plate B17. Bolt them to the steel floor plates and bond to the bottom and curved middle chine plates by epoxy resin using fillet bonding tecnique. They are braced at the top as shown. Transom and transom sheer plates may be laminated using either 3 layers of 5 mm plywood or 4 layers of veneer as in the case of middle chine plates. For transom sheer plates it may be preferable to use veneer as 5 mm plywood shall be difficult to bend at the ends. step 5 STEP 6
Fitting Upper Chine Plates and Sheer Plates :

Upper chine plate is screwed and bonded to the pre-molded middle chine plate upper stringers. Fore section of the upper chine plate is stitched and fillet bonded to the sheer plate. Aft section of the upper chine plate and sheer plate are combined and cut as a single piece.
step 6
Prepare and Fit Remaining Bulkhead Plates :

Cut off temporary extension to B11 and remove temporary bulkhead B17 and all bracing. Prepare and install bulkheads B3, B7 and B8-9 (port only), B10-11 (starboard only), B11 and B12-13 (port only), B13 (starboard only), B16 and B17-18 (port only), B19-20 (starboard only) and B21. step 7

under contruction

This is a personal project and I am working on it on a time-available basis.
Do you think you would like to build this boat - or any boat ?
See my Amateur Boatbuilder's Page first !
If you still want to build a boat and furthermore this one in particular, THEN :
NOT ONLY, I would be glad to provide plans and share my experience,
BUT ALSO, I may be able to provide the steel keel kit and the pre-molded middle chine plates.

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Last Updated on May 10,2001