ASSEMBLING A SPRAY 36
KIT (Now Spray 370)
Over the past thirty years the Bruce Roberts Design team,
lead by chief designer Bruce Roberts-Goodson, has produced hundreds of designs and
developed numerous building techniques from which over 20,000 boats have been built world
wide, including power and sail pleasure boats, commercial and fishing boats. From this
they have gained a depth of knowledge and experience allowing them to participate in
advanced computer development for metal boats which has resulted in a range of designs to
50 meters and of which the steel designs are now all available in "flat
pack" steel kit form for delivery world wide. All steel is "Grade A"
(St.44) with Lloyds certificate and cut on an "NC" driven plasma-oxygen cutting
With the advent of this computer assisted three dimensional
development it has become possible not only to offer the popular range of Roberts stock
designs but to include any steel design at a modest additional cost for the computer
development. Radius chine kits are available as well as single and multi chine packages.
These kits appear to provide the elusive link between computer-aided design and the latest
fabriCATAMARANion techniques. Individuals and shipyards, particularly small enterprises can now
benefit from modern cost-effective methods without major investment. With these
techniques, you can obtain millimeter accuracy with outstanding surface finish. To quote
from one builder, Roger Lasham, building a Coastworker 30 in the UK, "I had completed
the bottom plating which was only tack welded in place, yet when it rained overnight and
the wind pulled the tarp aside allowing water to collect in the bow, it did not leak away
so accurate was the fit".
TYPICAL SPRAY KIT
Looks simple! This kit saves hundreds of hours of
making patterns and cutting metal....See below.
Steel kits only require semi skilled labor for assembly and
all steel plates, excepting 3mm, are shot blasted and primed with "Sigmaweld-mc"
zinc rich primer which is especially formulated to allow the builder to weld the plates
without destroying the adjacent prime coating. Another feature of this weld primer is that
it does not give off toxic fumes nor is there any weld "splatter". As each kit
is "computer developed" and the parts are all nestled including all the plating
so that you can easily assemble the hull, deck and superstructure in a very short time
compared to conventional building and THERE IS NO WASTAGE. All windows, doors, scuppers,
prop and rudder tube holes are cut out and a pre-cut building cradle is supplied. The
Bruce Roberts organization is able to develop any existing design into a steel kit or
provide modifications to an existing design to be incorporated in a kit. They offer a
worldwide service and a special facility for builders and boatyards in developing
countries where kits can be supplied tack welded or fully welded and come with full
technical backup and access to the latest building techniques and designs. Labor saving
can be as much as 75% on conventional hull building times.
These metal kits are produced in such a manner that even an
experienced builder will save many hours on the preparation work because the plates,
frames, longitudinal and stringers and further necessary parts for the hull and
superstructure are supplied pre-cut and accurate. NO TRIMMING IS REQUIRED. All the parts
fit perfectly. On radius chine kits, the radius panels are rolled to the correct radius
and you will only need to trim the edges after you have installed the rest of the hull
plating which, does not need trimming. All plates have marking lines for positioning of
frames, etc. and all plates are numbered and come with clear instruction and part drawings
showing all items. Maximum plate size 6 x 2 meter. Metal kits are available in STEEL or
The following are a series of photo's supplied by our
Australian office that show the stages of putting a SPRAY 36
kit together. All the equipment that is needed is a welder, a grinder, a
lifting device and for the competent home handyman a spare four to six weeks..
|This Spray 36 is being built at Burnett Heads, Queensland, by a man
that has had no previous metal working experience at all. As you can see, the parts are
all numbered and fit together into precut slots. The plates are all marked where they fit
onto the frames. A foolproof method of building your dream boat.
Snipping the binders. This kit was delivered by flat bed truck.
Forward bulkhead. By studying the cut out shapes on the boat plans beforehand,all parts are
Frame part showing limber holes and the precut slots for the stringers to sit into.
All pieces are marked with code numbers that match with those shown on the plan.
Stringers, frames and solid floor webs laying out on garage floor.
Markings on plate where frames and stringers are first tacked, then after erection,
Unloaded pallet. This kit, weighing 7.2 tonnes took four men 1 hour to unload.
Concrete pads laid and cradle welded up.
The frames have been tacked together ready to be erected once keel and hull bottom plate
have been laid.
Floor webs being tacked to keel.
Floor webs in place showing lightening holes, notches for sole supports and stringers.
Bulkheads put into position and braced.
Frames and bulkheads starting to be erected.
All bulkhead and frames standing, stringers slotted into place and tacked.
Cockpit tacked into place.
Deck to cockpit bulkhead join. Perfect!
Side deck and cabin sides with windows cut.
Part only of the vast interior.
View of the transom
3D model of the interior layout. This has been made to scale.
The following is a breakdown of
the time taken to build this hull.
Arrival of Kit, sorting parts and preparing................... 2
Assembly of jig(s) and welding web frames.................. 2 men.......................3
Assembly of Hull & Deck, tack welding completely..... 2 men......................10
Finish welding Hull & Deck........................................ 2
Grinding visible welds................................................ 1
Total time should be between 350 and 400 man-hours.
The time is more or less reflected on the equipment and expertise available.
BELOW is another Spray 370 being
assembled in UK from one of our kits
Picture of us with the assembled S370 'A' Version kit hull
Hi Bruce/Edgar, Things going OK. The attached
photos are a little out of date now as the most recent ones are still in the camera. I'll
get them to you as I get them. Currently I'm working on the superstructure with the bow
deck and the two main saloon decks in place. The saloon sides are also in place held with
quite literally a couple of welds on the No 7 frame/bulkhead.The welder is inside the boat
so I've decided to tack weld working from the bow. I'll then move the welder through to
the cockpit, then aft cabin and then seam weld in reverse order - inside - i.e.. aft
cabin, cockpit, saloon then move to the outside, thus reducing the need to keep moving the
welder through unnecessarily. It's going OK. I hope to make some headway in a couple of
weeks when I'm at home for 8 days. I've got 8 weeks off in the summer (July & August!
No holiday - just more boatbuilding!) At the moment it's back to just the odd hour in the
evenings and occasional weekends.
She's a wonderful shape. I love her already! Thanks to you both
for the design and cutting.
I'm working on my own since the Easter Holidays so getting plates aloft is quite a
challenge - but I like challenges!I got three up today! Anyway I hope the photos are
OK.... Regards Andy