By Dana Castro

Operating independently like species evolving in parallel, with no
commercial incentive to market techniques or broadcast results, boaters
have generated an amazing proliferation of techniques, from neo-Cave Man
(aka the "Toyota method") to advanced Boolian-Techno Nerd in nature.
Being unfortunately afflicted with what my wife, friends, and I have
been forced to accept as an incurable, chronic disease (Chronic Boat
Tinkering Disorder, or CBTD for short), I have sprouted off in my own
direction.  Exciting trial, and saddening (and expensive ) error have
led me to a technique in which I have a cautious degree of confidence.

This technique will allow for a (relatively) high degree of control
which will produce a (sometimes) nearly factory look to the finished
product.  The boat modified as below is likely to be safer than those
modified by the crude application of vast force, which may produce
lopsided asymmetric modifications with weak spots or hidden cracks.
However, no matter what the level of sophistication with which you
approach your unsuspecting polyethelene victim, if you choose to modify
a boat you MUST understand "THE THREE RULES OF BOAT MODIFICATION"...

One is that flatter boats are (geometrically) less strong than full
volume boats to begin with, and when  modified, the risk of pinning,
wrapping, and paddler entrapment leading to drowning and/or injury may
be FURTHER INCREASED!  As a result you MUST exercise careful judgement
about WHERE and WHEN to paddle a modified boat.  If you aren’t willing
to REMAIN ATTENTIVE to this issue, the don’t modify your boat!

Secondly, do not expect a boat manufacturer to honor a warranty on a
modified boat.  Successful modifications may keep a paddler happy and in
the purchased boat, rather than saying disappointed things about the
boat and then moving on, frequently to another manufacturer's entry. So
while ultimately the manufacturers may benefit by the creativity of
individuals, do not expect a happy reception when you call with a
problem.

Thirdly, even though the techniques below will give you a high degree of
control, and even some ability to reverse changes you have made, you
must accept upon yourself the risk that you may not like your finished
product.  Modifying plastic is certainly still bit of a "black art", and
if your "colors run together",  you must be willing to accept this as
the price of exploring the realm of creativity.  So again, if and only
if you are willing to accept these premises, and to remain attentive to
them, should you try to tune into the "artist" in you  and put your boat
on the easel I will describe.

The modifications are done with the application of heat and pressure
and  allow the boater to  subtract from (or add to) the volume of the
boat, to make small redistributions to the volume, to add foot bumps,
and to change the nature of the rocker characteristics. This can be done
without cutting or welding the boat, and it allows substantial room for
creative experimentation and expression of individual taste without the
tremendous investment of time associated with the development of the
plug and mold necessary for a composite boat.  The changes, if
successful, may allow smaller, or less strong paddlers, including women,
and older paddlers to do more easily do specific "moves", and for
paddlers in general to expand their technique and experience.

The critical element in reshaping a boat is to be able to do this in a
controlled manner.  This requires the construction of a rudimentary
"boat jig".   To achieve a permanent and strong result, boat plastic
must be heated not only completely through its thickness, but also to a
point that the molecular bonds begin to loosen.  At this point it is
very soft, and relatively little force will induce a change in shape.
Control over the amount of force, the location of the force, and the
distance over which the force is allowed to exert itself is critical to
achieve the desired degree of change, and only the desired degree of
change.  (That is, if you get the plastic hot enough to loosen the
molecular bonds and try to use the "Toyota Method" you will end up with
a new type of boat called a "2-D".)   As well, the jig holds the
position while a slow and complete cooling process occurs.  All this
will enormously increase the tendency for the modifications to be
permanently maintained despite exposure to sunlight.  Inadequate,
irregular, or too rapid heating (and cooling) will surprise the boater
with all sorts of strange rearrangements of the plastic when the boat is
taken down off the roof after driving to the river on a sunny day!

The project will require two saw horses, about four 8 foot 2 x 4’s, some
¾ inch plywood, and a dozen or so 3 inch drywall screws. A few tools
will be needed, including a propane torch, at least four 18 inch or
longer bar clamps, and a saw such as a saber saw to cut rough forms out
of the 2 x 4’s. A power screwdriver (or drill) with a Phillips head
driving point is lots of help but not absolutely necessary.  This will
sound complicated but really, I promise, it’s not that big a job!

To begin with, measure the boat and subtract about 4 feet from the
length.  Set the two saw horses this distance apart.  Take two eight
foot 2 x 4’s and using 3 inch drywall screws attach them to the outer
ends of the saw horses such that there is a distance between them the
width of the boat.  (That is what the power screwdriver is for; if you
can screw those puppies in by hand you’re strong enough so that you
don’t need to modify your boat!) These 2 x 4’s will be referred to as
the "longitudinal stringers" of the boat jig.

Take the walls out of the boat (but leave the seat in), and remove all
hardware and grab loops from the decks, including drain plug.  Put the
boat on the saw horses so that it nestles between the lengthwise 2 x
4’s, overhanging each saw horse at the ends by the same amount.  Cut a
piece of  ¾ inch thick plywood, 3 feet long by 2 feet wide and put it on
the saw horse supporting the end of the boat - stern, probably - that
you wish to modify first.   (The plywood supports the bottom of the
boat, as opposed to having it rest on the cross bar of the saw horse,
which would dent the bottom.)

Adjust the position of the plywood piece so that the end  extends to the
end of the boat.  Without causing the boat to move, rope down the OTHER
end of the boat firmly to the jig so that if one pushes down forcefully
on the end to be modified, the other end will not rise into the air.
(The intended victim must not be allowed to escape!)

The next step will be to cut a "compression piece".  This is a section
of 2 x 4 about 20-24 inches long, which is placed lengthwise and on edge
on the center of the deck, which will be the region to which pressure is
applied. (As I will expand on later, the point to which pressure is
applied should NOT be the area that is heated and changed.)  The profile
to which this piece will be cut is made by holding the 2x4 edgewise on
the deck and, using a marker or pencil, tracing the deck profile onto
the wood.  Cut it to the profile and set this "compression piece" aside
for the moment.

Now you have a decision to make, and that is whether you want to change
the rocker.  Serious rodeo competitors will have their own set of
preferences here (usually less rocker), but for the all around
recreational play boater who will spend more time spinning in holes and
surfing waves than counting cartwheels, my recommendation would be to
add some rocker, especially to the stern.  It helps with back surfing
and flat spinning and does not noticeably hurt stern squirting or speed.
A little extra rocker will also help reduce pitons when rapids are
actually run.  In as much as the boat will tend to increase its rocker
as the decks are flattened due to the geometry of a boat hull, to add a
lot of rocker, you may (with the marker pen), accentuate the elliptical
curve on the compression piece.  To add only a little bit of rocker, use
the existing deck profile without modification.  Cut the compression
pieces along the marked line with a saber saw (or other), and place it
on the center of the stern deck.

The second means of controlling the induction of rocker is by adjusting
the fore and aft location of center of support under the boat (the
plywood piece).  This is accomplished by cutting a 3 foot 2x4 piece and
placing it crosswise on the longitudinal stringers UNDER the plywood
(but toward the end of the boat).  The plywood is then supported partly
by the saw horse and partly by the extra 2x4 piece, and by changing the
position of this 2x4 piece you will end up adjusting the point at which
the hull is supported.  If the support point under the boat is moved
toward the cockpit, the tendency to induce rocker will be lessened.
Taken to an extreme in which the pressure is applied while the bow is
"cantilevered" or unsupported from beneath, this may even reduce
existing rocker, while still reducing the volume of the boat.
Conversely, if the (plywood) support point is moved towards the end of
the boat the tendency will be to generate much more rocker.

Now, from 2x4 stock, cut two more 3 foot pieces.  Put the compression
piece back on the deck, right in the center.  Put one 3 foot 2x4 piece
crosswise towards one end of the compression piece and attach each end
of this cross piece to the longitudinal stringers (that parallel the
boat) with bar clamps set to a light pressure.  Put the second piece at
crosswise towards the other end of the compression piece and use the
other two bar clamps to hold this one in place, also with light
pressure.

Kneeling behind the boat look carefully at the deck profile and fix it
in your mind.  Measure the depth of the boat at selected spots,  if you
are not sure of you ability to keep the original profile in mind. On
second thought, measure the boat even if you are sure of yourself! After
a suitable period of time in which you admire your handiwork, you should
now crank in about 15-20 lbs. pressure on each clamp. If your mouth is
too dry to spit go no further; otherwise, you are now ready to light up
the torch.

To flatten the boat with rocker controlled by the above mechanisms, heat
the outer edge (i.e. the side) of the boat in an area about 1 inch wide
at the stern expanding to about 3 inches wide at a point just aft of the
cockpit.  If you only want to flatten the ends of the boat (but not the
cockpit region), do NOT heat the sides of the boat in the cockpit
region.  Heat both sides either by repeated passes with the torch.  The
torch works very well; it generates lots of heat and is very precise and
controllable.  However, you must keep the torch moving or you will melt
and burn the plastic (bad).  Holding the flame more nearly parallel to
the plastic as opposed to perpendicular to the surface may help. The
most critical factor here is patience.

After a while, perhaps five or more minutes, the plastic, which is now
about hot enough to burn skin, will get a characteristic shine that you
will learn to recognize and will begin to deform with the clamp pressure
applied to the compression piece. As if by magic the clamps will seem to
get loose; and the boat will only deform to that point.  The clamps can
be tightened up a bit at a time to make the boat flatter as desired.
Keep a close eye on the degree of rocker while doing this and control
the induction of rocker by adjusting the center of underneath the boat
as described above. Again, the key element in the heating is to get it
really hot, just short of the temperature at which the plastic will sag
without compression,  but not so hot as to burn or actually melt the
plastic.  It is also of note that different plastics need different
amounts of heat; more on this point later. Eventually the boat will
become "flat enough".  This is of course where the art blends with the
science and where the fun comes in. However, do not accept advice from
spectators drinking beer!   Allow the entire set up to cool overnight
and then repeat the process for the other end of the boat, if desired.

A second type of modification involves inducing concavity in the decks.
This can be done using the same set up.  However, it should be done as a
separate step; i.e., not at the same time as the flattening process.
Essentially the difference is where the heat is applied.  To induce
concavity into the deck apply pressure using the compression piece and
then heat two long skinny triangular bands of deck surface, parallel to
the compression piece.  The imaginary triangles are about an inch wide
near the tip of the boat and about 3 inches wide as you approach the
part where the deck starts to slope up to the cockpit.  Do NOT heat the
deck closer than  about 2 inches from either side of the compression
piece or you will end up not with a concave deck but instead with a "V"
shaped indentation in the rear deck.

If you do the bow and there is insufficient room left for your feet, do
not despair.  To make my boat perform the way I wanted I had to get it
down to the point that with my size 9 feet and 30 inch inseam, I could
not comfortably get my feet into the boat with neoprene socks on, much
less booties.  So a third type of modification is the addition of small
foot bumps.

The most difficult part of this process is simply finding a rounded
piece of  plastic or wood that can be used to push up on the inside of
the deck in the appropriate position, which is at the ball of the foot.
No special jigs are needed here, just a 1x2 or similar piece of wood
about three feet long and a couple of 4 inch lengths of 2x4.  One end of
the 1x2 pushes UP on the rounded piece of material, and the 2x4 pieces
create a fulcrum a foot or less back. By pushing DOWN on the end that
sticks out of the cockpit, a considerably upwards force can be generated
in a controlled fashion.

UNIFORMLY and gradually, heat an oval "donut" over the foot spot, about
8 inches by 5 inches, while exerting pressure up from the inside. Don’t
heat the "hole" of  the "donut",  (the very center of the oval.)
Presto, a foot bump will form.  HOLD the pressure until it cools by
tying or wedging the lever arm in position. Again, be patient, go slow
and it should work out fine. These won’t come out looking like they came
out of a mold, but if done carefully the appearance is not
unattractive.  This, by the way is the only instance in which will apply
pressure (pretty much) directly to the area you are heating.

Beyond these specific directions there are some generic issues to
understand when working with plastic.  One is that as mentioned above,
there are several different types of plastic, X-linked and Linear being
two of the most common.  Cross linked is considered tougher and more
expensive but difficult to repair.  Linear is softer, often making a
heavier boat, but is easy to repair.  Cross linked will absorb a great
deal more heat from your torch, perhaps twice as much or more, before
its shape will easily and permanently change.  This can be nerve
wracking but just be patient, eventually X-linked will soften fully  and
if the pressure is applied in the right places the deformation will be
clean and controlled, with no wrinkles, sags, or bubbled areas.  Just
keep the torch moving slowly, never pausing and burning the surface of
the plastic.  As mentioned, achieving the correct temperature is one of
the factors that necessitates the boat jig.  With this much heat,
uncontrolled pressure even of feet or hands much less Toyotas, tends to
cause excessive, localized deformations that will invariably be
asymmetric fore and aft and side to side.

Also as referred to above is the point that in most situations the heat
must not be applied to the place that is under pressure. Pressure is
applied "remotely" from the heated regions in that pressure applied to
cold plastic will stretch or bend the adjacent (hot) plastic which will
"distribute" the deformation over a larger area which will produce nice
smooth lines and no wrinkles. Beyond that be sure that there is only one
way the plastic can go as it becomes soft.  It’s sort of like cutting a
tree so it will fall in the direction you want; you have to visualize
ahead of time what will happen the plastic as it becomes soft.

Another point worth mentioning is that while you can modify boats quite
extensively with these techniques you can’t make a silk squirt boat out
of a sow’s Topolino!  Better results will be obtained by making what are
more in the line of customizing fit and flotation to a boat that started
out being at least ok.  It takes a few cojones to do this to a good
boat, but these modifications tend to be reasonably easy.  The
uninitiated who try to make a fighter plane out of an old blimp will
just end up with a dead old blimp.

Finally, what to do if a bubble or sag occurs.  Well, this is the only
situation in which you put pressure directly onto a heated area.  In
essence, heat the plastic and then press a large auto body squeege (or
two) against the sag until it looks right.  Wear gloves, too, dummy!
Then hit it with  water from a spray bottle to freeze it in place.  If
you don’t  like the result repeat the process until you have it right.
This by the way is the only situation in which you may rapidly cool the
hot plastic.  Allowing the bonds to reform slowly will substantially
increase the permanence of the changes so that even when baking in the
sun on the roof of the car, the boat will hold its shape.  As a last
resort a palm sized random orbital sander will do a surprisingly good
job at smoothing out roughened or slightly wrinkled plastic.  A few
quick torch passes will restore the shine.

Assorted details include the (obvious) fact that you will in most cases
have to cut down the end regions of the minicell walls.  Remember that
as I stated at the outset these modifications may reduce the strength of
the boat.  Don’t forget the THREE RULES OF BOAT MODIFICATION when you
get on the river!

Foam foot blocks may in some cases be necessary as foot braces may no
longer fit. Use minicell for this purpose.  Start out with triangles
that are too big and cut and sand until they fit. Proper fit should
leave a slight clearance between the block and the inside surface of the
deck so that the foam does not try to re-expand the boat shape.  The
best sanding material is 36 grit sandpaper, no higher.  If you like you
can glue them to what is left of the front wall  for greater security.
When done right they are real comfy and warm and secure, and if you do
piton, you can’t slip past them like you can with foot pegs.

Now at this point one might say, "why not just get a squirt boat?"  Well
this is a different type of animal, so to speak.  As a long time year
round squirt boater (I’m in recovery from that one) on all sorts of
water including the Upper Yough, I can tell you that there is a
drastically different feel to a boat with a low volume cockpit region as
compared to a playboat with shrunken ends.  The squirt boat does its own
special things that nothing else in the world can duplicate.  However,
while very small,  these modified plastic boats are comfy, they have
nice back rests, they float nicely (even in rapids), you can key hole
exit from them, and of course you can smash them on rocks all day
because they’re plastic.  As I get old and weak I come to appreciate
these things.

Now once again, let me emphasize RULE NUMBER ONE, the safety issue...
These modifications will detract somewhat from the resistance of the
boat to fold its ends over obstructions.  Certainly do not use a boat
modified in this manner for steep or shallow rocky or wooded creeks, and
be even more cautious than normal when encountering pinning
possibilities in general.  That said I do find that the boats that I
have modified this way have been able to take a terrific pounding on
rocks at play spots without complaint.  As well they turn on a dime and
with practice the attitude (bow up or down) of the boat can be
controlled quite precisely.   Whatever modifications are made, they
should not be done in a manner that will interfere with the ability to
make a "key hole" type of exit.

The point, though, is not to go "crashing down hard stuff", but to have
fun, exercise, and challenge "doing the hard stuff" in the safer places
where all the forces of the river become focused together into big
crashing funny looking white things.  Properly set up for an
individual’s weight and ability, these modified boats excel at
multiplying the fun factor, in a more individual sort of way.  Skills
become sharpened and reactions quickened as one spends time in the
small, low volume boats, and these skills will in time become ingrained
and stay with the paddler even when switching to the "big water boat".

Finally there is the creativity factor.  I enjoy the relentless newness
of the river, even after close to two decades of white water paddling.
I especially find the play spots to be forever different.  Even at the
same water level a hole will always seem to find a way to do something
to me that is in some way at least slightly new.  When off the river, I
(and some others), seem to enjoy extending this exploration even to the
venerable plastic boat itself.

Regards, dana castro

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