The Bruce Roberts Steel or Aluminum kits
All plate parts belonging to the hull, deck and superstructure that are accurately cut to
size are included. The parts are marked with the appropriate part number and engraved
matching marking lines to assist in the assembly and location of the part in its position.
All framing, stringers, engine beds, 'T' sole bearers, deck beams, deck stringers and all
exterior plating, plus 3 steel bulkheads and stiffeners is included. Windows and doorways
are cut out as required.
In the case of radius-chine hulls, the radius plates a rolled to the perfect shape and NO
fitting is required. Complete assembly and engineering boat plans supplied. A building jig is
supplied with the kit. Delivery is often included in the quoted price.
Cutting method is Plasma / Oxygen, ensuring highest accuracy and smooth edges. Plate parts
are cut from either Marine Grade ALUMINUM or Grade ?A? Ship-building quality STEEL that
has been coated with factory applied Sigma weld MC welding primer. We use and
recommend steel plate that has the official designation ISO standard 10474 or EN 10204
with 3.1.B certificate.
All pre-primed profiles belonging to the hull, deck and superstructure are supplied in
sufficient quantity and are in factory lengths of 6 M / 20 ft, coated with factory applied
Sigma weld MC welding primer.
Openings for windows and doors can be cut or only marked as per customer's preference.
Bulkheads are supplied complete with stiffeners and are in accordance with Classification
rules and safety regulations. Cold forming of plate parts is included where this
requirement forms part of the design. Basic engine foundations are integrated into the
A Setting up jig with the correct shape of the hull plates that can be used as building
jig for the entire hull after reinforcement plus there is a extensive building manual
including detailed drawings, parts list and welding instructions.
In these days where both the local authorities and the better informed builders
themselves, it is important that the construction calculations are in accordance with
prevailing Classification society so this factor is part of the preparation of any Bruce
Each kit or set of cutting files comes complete with about 20 sheets of detailed assembly
drawings with written instructions and check measurements for assembling each part of the
kit. The drawings cover assembling the frames, setting up the building jig (supplied) on
to I beams or similar base. These extensive drawings take you right through the welding up
process from start to finish.
Also are included several sheets of detailed engineering drawings that cover the
installation of the main engine(s), ?take home engine?, generating set, exhaust systems,
fuel systems, fuel and water thanks etc.
METAL KITS ASSEMBLY INSTRUCTIONS:
1: INTRODUCTION. Throughout these instructions we
will use the word metal which may apply to steel, aluminium or copper-nickel. There will
be variations between the handling of the various materials and these will be drawn to
your attention as necessary. YOU WILL NEED TO READ and absorb all these instructions
BEFORE you start the assembly of your kit. These instructions are intended to introduce
you to building from a kit but are NOT intended to replace good metal boat building
practice. If you are not already a competent welder then please seek assistance.
Few of you will understand (or want to know!) the huge
amount of work that is required to turn any boat plan in to a cut-to-size boat kit. Every
part has to exactly match that of its neighbor, the slots need to be exactly in the
correct locations and everything must fit perfectly together to enable you to complete the
assembly of the hull, deck, and superstructure with the minimum of problems.
Despite our best endeavors and attention to detail in
developing the kit and the cutting of the metal parts, some parts may not fit or appear to
have the wrong shape. Before rushing to cut and or shape parts to fit the hull, carefully
check the drawings and measurements from the surrounding parts to ensure that nothing else
The first thing to realize is that the kit differs in many
ways from the methods you would use to build a metal boat from scratch. The kit is far
superior to anything you could achieve by starting with the boat plans and delivery of raw
steel plate and the various profile bars that are needed to build your metal boat.
Most metal boats built from scratch are built
most boats built from cut-to-size metal kits are built UPRIGHT.
Not only is this a more appropriate way to assemble the kit but also it saves cost and
inconvenience of having to turn the hull.
To make sure that you take notice of one very important
piece of advice, we will state it here as well as at the appropriate time:
YOU MUST TACK WELD THE
COMPLETE HULL DECK AND SUPERSTRUCTURE TOGETHER BEFORE YOU RUN ANY FINAL WELDS.
Failure to observe this advice will almost certainly
ensure you will end up with an unfair boat requiring a considerable amount of filler. In
any case do NOT OVER-WELD or try and run long welds at one time.
2: RECEIVING YOUR KIT.
Depending on your location or delivery arrangements your kit may arrive on a flatbed truck
or in a container. You should be aware of these arrangements before the actual date of
delivery so you can make the necessary preparations to receive your kit.
The kits are normally packed on pallet(s) and can be
lifted off the transport using a small crane, front-end loader, or similar equipment. You
may find it more convenient to "drag" your kit from the truck or container using
a pair or planks as a ramp. Once you have unloaded your kit you must make provision to
keep it covered until assembly is underway. Make sure that the metal parts are not in
direct contact with cement-based floors like concrete, as this will affect the Sigmaweld
You should go trough the kit and identify each part or
group of parts so you can store these in the order that they will be required. Due to the
requirement of packaging for transport it is impossible for the kit manufacturer to stack
everything in the order you will be using the various parts
you must take care of
this. Later in this text we will suggest the order of assembling your kit so you will be
aware of which parts you will need at each stage. If you do not find a particular part at
DO NOT PANIC
there will be so many pieces that it will be easy for
you to overlook one or two at this stage. If after several checks you find one or more
parts missing then do contact the supplier of your kit so they may put the matter right.
3: ASSEMBLY SEQUENCE.
FOR MOST HULLS: The first item you will need is the setting up jig. The metal
"castles" that come as part of your kit will support the transverse profile
jigs. The setting up jig is intended to get the assembly of your hull started and is NOT
INTENDED TO SUPPORT THE BOAT during the entire building process. After you have the
bottom plates tacked together you should consider adding extra support and bracing to the
For most hulls, the general assembly sequence is:
Assemble the jig.
Bottom plates into the jig; line up the markings for
frames and tack weld together.
Assemble web-frames in accordance with drawings.
Position bottom longitudinal stiffeners on bottom plates
(very small tack welds only).
Position frame over longitudinal stiffeners onto bottom
plates, starting with the middle frame, work your way aft ships and then from the middle
to the bow.
Tack-weld frames in position, observing the markings on
the plates indiCATAMARANing the correct position of the frame. The direction of the arrow in the
marking indiCATAMARANes the direction of the plate thickness. Always start tack welding at the
bottom centerline working your way outward.
Tack-weld bottom longitudinal stiffeners to web-frames
Insert side longitudinal stiffeners into web-frames and
continuously check the frame spacing.
Position side-hull plates starting at transom and tack
weld to web-frames only.
Tack weld longitudinal stiffeners to side and aft-hull
plates. For hulls with build-in spray-rails start at the bottom and work your way upwards.
Position rear hull panel (transom) and tack-weld to bottom
and side plates.
Position longitudinal deck-stiffeners and tack-weld to
Position deck-plates starting aft and tack-weld to
Tack-weld deck-longitudinal stiffeners to deck plates.
Position superstructure walls and tack-weld to web-frames.
Position and tack-weld roof-plates to deck.
This is the recommended sequence for most type hulls.
Depending on the facilities of your workshop and building site, variations may be required
or preferred. The better equipped your workshop is with overhead lifting equipment and
equipment the easier and more smoothly will your job proceed. We do recommend that you
read some of the literature available on metal boat building, which will answer many of
those general metal boat building questions that are sure to need clarifying as the
project proceeds, if only to get familiar with the terminology of parts and components of
your kit. Contact your supplier for titles available in your area.
FOR HULLS WITH LONG KEELS INCLUDING SPRAY TYPES:
The Spray and similar hulls are unusual in that the keel
structure should be assembled at the same time as the bottom plating. Take care that you
do not "squeeze' in the tops of the keel, use the webs as spacers. After you have
positioned the bottom plates, the keel sections and the transverse profile jigs in their
correct location you may start to tack weld the bottom plates to the keel sides.
FOR SAILBOATS WITH FIN KEELS:
Sailboats with deep keels will have the keel installed
after the hull is completed. The "canoe body" should be built from the bottom of
the hull upwards in a similar manner used to assemble a powerboat hull. The webs will be
arranged so you can later add the keel after raising the hull into the correct elevation.
The idea of this method is to allow you to work on the
hull deck and superstructure while the boat is lower and thus more accessible. The exact
method and order of assembly may depend on the availability of lifting equipment and your
general work environment.
In most cases you can start by laying the bottom plates in
the transverse profile jigs and with the aid of the "castles" so position the
plates that you can start to tack the hull plating together along the centerline. You will
next be able to install the bottom sections of the frames and webs in their correct
5- WHAT YOU NEED TO KNOW ABOUT WELDING
Attempting to construct a metal boat kit leads us to
believe that at least the basics of arc and or Co2 welding are known. If in doubt about
your abilities to weld, improving your skills on some scrap pieces of metal would be
advisable as there are no great secrets in general steel welding but practicing would set
you of to a good start right at the beginning.
Welding aluminium or copper nickel should not be attempted
without proper knowledge of the materials and welding sequences involved and should always
be carried out in covered and clean surroundings.
The metal kits are constructed in such a manner that the
strength of the hull & deck is created from the build up of the frames and stringers
as interlocking sections, HEAVY AND CONTINUOUS WELDING OF FRAMES AND STRINGERS SHOULD
BE AVOIDED AT ALL TIMES.
Especially important for all plate joints during the
assembly of the hull is DO NOT APPLY CONTINUOUS WELDS. The plate joints should be ONLY
TACK WELDED in three locations, one weld at the each of the ends of the join and one
in the centre of the join. These tacks should be no more than 2 inches or 50mm long. If
you weld the plates on the floor you will end up with a "hard-spot" in the hull
All parts of your kit are cut to a precision of 2 mm and
are designed to be welded together without any opening between the parts. Some plates will
need to be beveled before tacking in place or you may prefer to make the bevels after you
have tack welded the plates and just before running the final welds. In all cases good
metal boat building practices will prevail.
After the hull & deck are COMPLETELY TACK-WELDED
together, the process of finishing welding can take place. The secret of creating a fair
hull & deck after tack welding is completed is to use a fairly high amperage and speed
setting of your welding equipment. Welding with too low amperage and slow speed will
create lots of heat on the spot and less penetration of weld material in the seam, causing
strength problems and lots of grinding weld material away to obtain a smooth surface
afterwards. This in turn would weaken the weld again.
Using common sense and practice should leave you to create
a smooth and fair hull & deck structure with very little distortion. IF IN DOUBT
ABOUT YOUR SKILLS, SEEK ADVICE.
Any metal construction company or competent welder can
help you with the basics. Always observe personal protection and safety regulations.
6. ASSEMBLING YOUR KIT.
With the arrival of your metal kit, you received a packing
list containing the names, numbers, and quantities of all the parts in the metal
package.You also received one or more large-scale drawings showing all the parts as flat
surfaces and more or less grouped together as they appear in the metal kit and a number of
small drawings showing the assembly of the frames with the appropriate measurements.
Studying the large scale drawings will give you a first
insight in the position of the various parts and it becomes apparent that the numbering is
as much as possible a logical sequence of the way the parts assembly progresses.
Prior to using these drawings, we advise to make some
copies of the drawings or parts there off or cover them with plastic as they could easily
be destroyed during the construction and welding.
Using the packing list and the drawings you can now make a
check to see if all the parts are present. For ease of recognition you will find that
frames etc. are numbered with 4A, 4B, 4C etc. thus every time you find a number 4 and
extension A or B etc., they belong to the frame no.4.
The cutting, collecting, and identifiCATAMARANion of parts
during production is a manual process. This is why parts may be given incorrect numbers
and even get lost, in spite of our thorough quality and quantity control procedure.
Checking and verifying all parts against the packing list provided and keeping
unidentified parts aside until the end enables you to identify the missing parts and
incorrect markings on parts for clarifiCATAMARANion with the supplier.
Apart from the plate parts, your kit also includes a
selection of profiles, supplied at factory lengths, as listed the Packing list. Each bar
needs to be cut to the length required in its position in the construction as detailed on
the Construction Plan provided in the set of drawings.
Now that you have collected and sorted all the parts, the
frames can be tack-welded together by using the small drawings and the given measurements
Prior to welding, use an angle grinder and create a
"V" of approx. 60° at the seam to be welded.
This means 30° angle at each plate edge. Doing this will
give you better penetration of the welding material, adding strength to the hull. We use
the word tack-welding again as it would be tempting to finish welding the seams
Some models have flat or angled bars added on the inside
edge of the frame plates for additional strength. Check the Construction Plan provided.
These so called Girders are best fitted as soon as the frame parts are tacked together,
before placing the frame in its position in the hull.
On larger boats it might be an advantage to only weld the
bottom parts of the frames together and put the side frames up after the frames are in
place on the bottom plates. Your own judgement is important here.
Having prepared all the frames in this manner it is now
time to prepare the building jig.
With the metal kit you have received 2 or more jig parts
as shown below.
These supplied parts are only initial shape supports
and CANNOT BE USED AS FULL BUILDING FRAME WITHOUT SUBSTANTIAL STIFFENING AND CROSS
The supplied jig parts could be placed on a concrete
underground, leveled, and stiffened.
In case no solid underground is available, the use of a
couple of heavy RSJs picked up from a
local scrap dealer could do the trick. The distance
between the jigs is determined by the position of each frame (web) in the hull, whereby
the jig number is the same as the frame number (f.e. Jig-part J5-2 is at frame 5).
In case the "jig" parts stay in place during the
entire construction, it would be advisable to tack-weld a flat bar across the top of the
plates to spread the point loading and avoid possible damage to the hull plating.
Now place the bottom plates on the prepared jigs or
building frame and tack-weld together at a number of points.
We refer here to paragraph 2 in relation to sailboats like
the Spray series where also the keel is placed under the bottom plates at this stage.
For those of you who are new to this type of boat
building, having placed the bottom plates on the jigs, it seems they are never going to
Start tack welding at the location roughly in the
middle or somewhat aft of the middle after lining up the lines on the plates and position
of the plates.
When you now go forward or backwards from the tack-welded
position you can help the plates get in shape by having some helpers pull up the sides and
using a trolley jack underneath the middle join of the plates until the seams touch. Now tack-weld
at this point and go to the next position. At the bow you would probably need a hand block
and tackle to pull the sides of the plates together as some tension will be experienced
DO NOT FORGET TO SECURE THE POSITIONS OF THE CLAMPS
AGAINST SLIDING AWAY.
Having finished tack-welding the bottom plates
together, start placing the longitudinal stiffeners at the markings on the bottom plates
whilst lining-up the slots with the position of the frames (webs), as indiCATAMARANed by lines
on the plates and use the large scale drawing(s) as reference. Only tack-weld these
longitudinals to keep them in place for the time being. As frames will have to be slotted
over these longitudinals, we recommend to tack-weld only to the bottom plate in the middle
between frame positions, which allows you to align these when putting the frames in
Then start placing the frames (webs) which slot in the
longitudinals. Position the middle frame first and tack-weld it to the bottom-plates in
the centre, then pull up the bottom plates towards the frames until they fit snugly and tack-weld.
Depending on the shape of your hull, we recommend to work
your way aft first, thereafter from the middle to the bow.
If you have put the frames together completely, use some
temporary bracing on the upright sides of the frames, as they are likely to flop about a
Now we place the stringers in the slots of the frames on
the sides and slightly tack-weld at some spots to keep them in position.
We do emphasize again, ONLY TACK-WELDING.
At this stage you have already created a strong and solid
base of the hull and the time has come to bring the side plates into position. This is
best done by using a simple overhead gantry or the use of a forklift truck.
Pick up the side plate(s) by using a plate clamp on a
chain connected to a block and tackle or forklift leg, make sure the plate is more or less
in balance when it is hanging in the air and bring to its alloCATAMARANed position.
Use a helper to put a point of the seam in the right
position and tack-weld.
Continue by moving the plate up or down a bit with the
block and tackle until the entire side is in position and tack-welded. Place some
tack-welds on the uprights of the frames as well.
The side plates nearer to and at the underside of the bow
will show some tension and can be pulled in place by attaching a chain on the outside of
the plates and pulling them into position.
To attach a chain and/or block and tackle to a plate,
tack-weld a temporary eye or something similar to the plate. By only welding on one
side of such plate(s), you can easily remove these again by bending this plate until
the weld breaks.
Note: In the case of radius chine sailboats, the
radius chine sections are not used at this stage; we will come back to those later.
Next the transom plates, bathing platform where applicable, stern plates and all other
plates belonging to the hull are offered up in position and tack-welded in
Especially where rounded corners are used, offer the
particular plate up to the position it is to be used and check or make the correct radius
in the plate prior to tack welding.
REFER BACK REGULARLY TO THE DRAWINGS AND CHECK
INTERMEDIATE AS WELL AS OVERALL DIMENSIONS.
Now the deck plates, superstructure, fly-bridge where
applicable and all other super structure plates can be offered up to the hull and tack-welded
into position using the gantry or forklift truck to lift them onto the hull.
Do make sure the support strip(s) under the deck and cabin
roofs, where applicable, are placed first in its slot(s) in the frames and beams.
In those cases where professional lifting equipment and
space is available, an option would be to tack-weld the superstructure together at floor
level, braise temporarily and than lift the entire sub structure onto the hull.
FOR RADIUS CHINE HULLS:
Having tack-welded the entire boat together, you now turn your attention to the
We have supplied you with the appropriate amount of
section to fit in the left over opening in the hull.
As you checked the metal kit on delivery, you have seen
they are all similar sections, just one radius rolled into them.
Now you can carefully hold a section against a position on
the opening in the hull and using a helper scribe the plate with a sharp tool or pencil
and grind, nibble or cut the edges until the plate fits in position.
Tack-weld into position and continue until all
radius plate sections are in place.
CONGRATULATIONS, you are now looking at the shapely
result of your perseverance.
Of course you have run into some difficulties during the
building process and maybe even cursed a couple of times but it must be clear by now why
we told you time and time during this manual ONLY TACK-WELDING. Any possible
mistake you may have made was fairly easy to rectify, as you only had to grind a couple of
small welds away.
However careful the cutting of the material was prepared
and cut, the material can behave unexpectedly, for example the grain in the plate runs
diagonal and will resist shaping into the required form. This will require additional
effort and force to get the plate to fit.
Although we aim for perfection, mistakes do occur, however
the general consensus is that if you have to cut or reshape a plate (with the exception of
radius plates) somewhere something is not right.
7. FINISHING THE ASSEMBLY.
Now the time has come to finish the welding process.
Firstly, finish welding all the seams between the frame
sections applying a full weld. All slotted connections between frames and bottom and side
longitudinals are to be welded in full on at least two opposite sides of the connection.
Then apply intermittent welds on all frames and stringers
to the hull and superstructure plating using the rule 50 mm. (2") weld, 200 mm.
(6") clear, 50 mm. (2") weld. Alternate the weld one side of plate, other side
of plate and so on.
DO NOT CONTINUOUSLY WELD ON ONE SIDE OF THE HULL
but weld a bit one side, the other side and so on to avoid pulling. Do not underestimate
the forces coming free when welding.
Now the hull should be welded.
In case you have not made a 60° "V" between the
seams of the plates yet, no problem, use an angle grinder and cutting disc and cut a
groove in the plate where the seam is loCATAMARANed. Not as nice as having a "V" made
first but the result will be the same. As explained before, alternate welding from side to
side and finish the welding process.
The hull under the waterline must be welded inside and
out. All other welding can be done one side only.
Grind away surplus welding whereby we advise to pre-grind
the welds with a heavy duty grinding disc and finish grinding with one of these softer
flexible discs, ready available in the trade, to avoid having to use filler on the weld
seams.Clean the surface and apply a coat of primer and the basics of your pride and joy
are ready for finishing.
We recommend you postpone the engine as long as you can, not because of the
weight, more because these parts cannot be placed in their final position at this stage
and tend to be very much in the way / get damaged easily as long as they are only
temporary supported inside
If you still prefer to lift the engine in, no problem as long as you make sure that you
spread the weight of the engine over at least three transverse frames and always over two
Use some serious timber beams running parallel to the CVK and support the beams on the
lower horizontal part of the transverse frames.
Obviously best to skip # 9 which is still loose by putting some extra dunnage on the
adjacent frames to raise the timber beams. This will also give you sufficient room to run
final welds at the bottom, especially important for the welding of the keel from the
Handle the generator in the same way. Before you do all the above, make sure your hull
plating fully follows and touches the cradle parts that have the same shape as the hull on
Finally, when placing the engine in it's temporary position, put it in a place not
interfering with your longitudinal alignment check which should be done at regular
intervals during the assembly process.
For the tanks, assuming you will be using pre-fabriCATAMARANed tanks, I would recommend to leave
those loose and get them inside the hull when convenient. (normally make nice chairs or
tool shelves during the assembly). Weight is not an issue here.
The shape and dimensions of the tanks should always be checked in place (as would the
fuel-tightness), very difficult to modify tanks or tank brackets when hull closed.