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on the raked fin tips to maintain an appropriate
shape for good performance. If the fin will not
be stored in this manner, or if the fin is packed
in a gear bag for transportation, fold the fin tips
over the topside of the aluminum foil and secure
them in place with rubber bands. This will help
prevent them from becoming deformed. Fin tips
that have become misshapen can be worked
back into shape by massaging the plastic with
the hands until the desired curvature has been
achieved.
The fin tips are held in place by a bungee system internal to the hydrofoil. If this internal
system breaks, the fin tips will be free to come out of the foil which would have a
significant degrading effect to the monofin’s performance. The ends of the bungee system
that attach to the fin tips should be visually inspected prior to diving and compromised
parts should be replaced. This system is comprised of bungee, nylon cord and plastic zip-
ties. The parts are inexpensive and easy to replace. A foil without fin tips can suffer about
a 50% performance reduction, so do not allow simple, easily repaired hardware to become
a safety hazard. Maintain the redundant bungee system for the fin tips so that they are not
lost while swimming at depth. With redundancy in place, if either bungee fails on a dive,
the monofin’s performance will be unaffected unless and until the other remaining bungee
also fails. New fin tips and bungee systems can be ordered from Smith Aerospace Corp.
and can be installed by the owner to an existing fin, or installed at the factory on a new fin.
When replacing worn bungee systems, make sure to return the fin tips to the same ends of
the foil from where they came or the curvature in the fin tips will be opposite from the
desired curvature. When installing new replacement fin tips take care to install them with
any preset curvature aligned in the desired direction relative to the foil to avoid extra work
shaping the tips. When new tips are installed it is recommended to begin storing the fin as
described above and shown in
Figure 6,
to get the proper shape set into the plastic. The
longer it sets with the proper shape the more permanent the shape will become to the
plastic. Divers can play with changing the amount of curvature and twist the fin tips have
in order to customize the feel and balance of their individual monofin. This is a subtle
method by which divers can optimize their fin’s performance to their individual swimming
style.
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Youtube video “DOL-Fin X-20 Fin Tip and/or Bungee Replacement” provides a complete
tutorial on how to replace fin tips and/or bungee assemblys. This video can be accessed
here: (
http://youtu.be/pJzDBW7KE2c
). The following explains the process in words.
To install a new bungee system, begin by fastening one end of the bungee to one of the fin
tips with the loop string and plastic zip tie. Thread the loop string through the loop in the
end of the bungee and then through the forward hole in the fin tip. With the loop string
threaded through these two parts, bring the free ends of the loop string together and then
fasten them together with the zip tie tightened to form about a 1 cm loop. Trim the excess
tail from the zip tie. Adjust the loop such that the zip tie is biased closer to the bungee
than to the fin tip so that it will not interfere with folding the fin tips later on. This can
also be adjusted after assembly if you find that things moved around on you. For the
redundant bungee system, repeat this step using the aft hole in the fin tip. The next step is
to pull the bungee assembly through the aft hollow of the hydrofoil. This can be
accomplished using a wire, or a string, to pull the bungee(s) through the foil. Then, with
the already fastened fin tip installed into one end of the foil and the free end of the
bungee(s) stretched through and exposed on the opposite end of the foil, use the remaining
loop string and plastic zip tie to fasten the remaining fin tip the same as the first fin tip was
fastened. A useful trick is to insert a pencil through the loop ends of the bungees to
restrain them in place to keep them from receding back into the foil while the second fin
tip is being installed. Once the strings are looped through the bungees and fin tip holes
and zip tied in place, the pencil can be removed and the fin tips inserted into the foil ends.
Warranty:
As the DOL-Fin series monofins are Experimental, there is no warranty expressed or
implied. This is primarily for liability reasons. We have done our best to make this
hardware as tough and durable as possible. If your DOL-Fin should prove to be defective,
we will assist you in finding solutions to get your hardware back into functioning order, so
please do not hesitate to contact us and let us know your situation. Each case will be
different, but historically, we have often supplied replacement parts at no cost to the
customer, or for the price of the shipping.
