Plywood Boatbuilding for Virgin Builders - Part 3
by Dick Koepp
Continued
Planking:
First, assuming that you have all the skeletal
frame members installed and faired smooth and true to the lines of the
planking which will attach to it, now you must come to a real test,
installing the planking. For purposes of this article, I am ONLY
addressing plywood planking here.
Tip here, paint as much of the interior surfaces of
the inside of the boat as is possible now, it is easy to reach the
undersides of the frames, etc, and will be tough to do once the boat is
turned.
Now, the key here to successful planking is to
lay out your planks carefully before doing any cutting or gluing.
"Dry fitting" is a must here. Start with the stern (transom)
planks first. There are several reasons for this: first, the surfaces are
usually almost flat, thus making it all so much easier, second, no
bending usually, and third, easier to fasten. Since most boats use
standard 8' plywood sheets, you will have to connect two panels
together as you move forward in the boat bottom. The two sides of the
planks will meet over the keel and will be fastened onto and into the
battens and frame members (based on the plans). Leave plenty of overlap,
dry fit and mark each panel, NOW you must decide where to do butt joints
covered extensively in Glen Witt's must-have book: Boat Building with Plywood. Butt joints must fall
between frames, so you have to dry fasten or measure correctly. Be sure
that you lay in the forward panels also before you fasten, because you
might have moved a panel for what ever reason, and don't want to come
up short at the bow (which actually happened to me!). The forward panels
most likely will need to be bent or "steamed" into position.
(See previous article on Steaming with hot water and rags, Web Letter
9). These are gonna be the toughest panels to install, so you need to
really be careful. Take your time and use gaskets, temporary screws
and/or clamps to hold things down while you measure and carefully cut off
the excess from the panel. Sides: once you have installed the bottom
panels completely, allow them to dry for 24 hours, then set about
trimming the side edges of the chine smooth and fair, using a scrap piece
of plywood to let you know how it flows. Once this is done, install the
sides, again, be aware of any butt blocks and allow for them between
frame members.
TIPS: Once all panels are rough cut and dry fitted,
you need to mix up a big batch of glue, go overboard, running out will
spoil everything! Get someone to help you. It is so much easier and
quicker with a helper. I do not use ring nails anymore, not with the
advent of the new generation of power screw drivers. I pre-drill,
countersink and start every screw in every hole in each panel ahead of
time. True, one could just snap lines and drive screws without a pilot,
but you will NEVER get them all to go below the surface, and the
resulting effort to sand them down is God awful! Use clamps and gaskets
as needed (see previous article). Once the glue is on, and the panel
positioned, drive the screws as quickly as possible. When all is
installed and dried, fair the hull and make it smooth over its
entirety.
Time to Fiberglass:
As stated elsewhere, the whole subject of
fiberglassing is covered better in other books. Here I just want to point
out some things I have learned to try and make the hull turn out
"clean looking" and smooth. First, be sure you get rid of ALL
holes, gaps, gouges, etc. Use a hard setting wood putty and build it up
in layers if necessary. But be careful, if you have ended up with a
significant gap, say somewhere at the keel, you really need to ask a pro
for advice. Putty will not correct a fatal flaw. It is used for cosmetics
only, remember that!! Now is the time to add any other wooden members to
the hull, such as a keel log, lift strakes, or splash logs (follow your
plans as to how to apply each of these). Ok, so everything is fair,
puttied, and sanded, now apply your fiberglass cloth per the users
instructions.
Tips: Always use gloves, always buy extras of
everything you need. You will use them I promise. I keep a ton of old
coffee cans stored up for the time when I will start fiberglassing. Also
stirring sticks, a whole load of extra catalyst. And the most important
tip of all, NEVER EVER try and fiberglass below 60 degrees!! Even if you
have to heat the building site, you must have heat to set up the resin.
Based on the system you use, polyester or epoxy, you will need to prepare
the surface for the finish paint. NOTE: Fiberglass boats built this way
do NOT have a gel coat yet. New to the scene, modern after-the-fact gel
coats are available, but I have not personally used them. Any Fiberglass
finish coat should be painted either with a gel coat type, or marine
grade enamel (again follow the paint's instructions). But remember,
fiberglass alone should have a protective paint applied in all
cases.
Now for the real fun! Turning the hull right
side up!
There was no other task more foreboding in my
experience than trying to engineer turning a hull over with a minimum of
manpower, and without the assistance of a crane! But take heart! It can
be done! The most important thing is to THINK and PLAN! Most of the plans
I have gotten from Glen-L and elsewhere, don't say a word about
turning it over. Now I know why! There are no "right ways" to
do it. Everyone takes a different tack. In my case, I loosen the building
form from the floor and always turn the boat with the form INTACT. The
reason is that the form adds considerable strength and rigidity to the
boat. SO whatever method you come up with, you need to account for the
form being there in any turning radius. On a small runabout, turning can
be done usually with 4-5 people helping. One thing though, I would take a
minimum of two 2x4x8's and temporarily clamp them from gunnel to
gunnel about 1/3rd of the way from both ends. The excess portion of the
2x4 will then touch the floor first, NOT the edge of the gunnel, thus
saving the gunnel and distributing the weight of the boat while on its
side evenly over the whole structure. Before you turn the hull, make sure
you have thought about where it will go once it's turned. Sounds real
basic, but believe me, you won't want to start building some blocking
to level the righted hull after you turn it. It's easier to do this
while the boat is upside-down. I build long carpet padded
"forms" that match the hull contour, and have these spaced out
and installed into the floor area where the final work will be done.
Remove the two lifting 2x4's and then remove the building form.
Hull space, encapsulation, flotation:
Once the hull is trued up, level and won't
move on you, begin thinking about how you will finish the inside. This is
very important because most wooden boats will take on plenty of water in
regular use, to start dry rot immediately. You might as well do this job
right. I believe that encapsulation with epoxy resin is the best all
around method to use for ensuring that the interior will be dry, and
non-accessible to water damage. But you have to think ahead (see I told
you this was all about thinking and planning!). Some areas of the hull
must be done now, before any thing else is installed. Once you close a
space in, you hide it, and in essence have kissed it off to eventual dry
rot! Take the time to carefully seal all wooden parts. Try to anticipate
possible places where you might need to add glued members later for the
cabin, or whatever, but it can be done. When the hull interior is sealed,
you can now proceed on to the best part of the job, building the topsides
to meet your unique needs. More on this in the next article! Good luck,
and remember, I welcome any and all comments, questions etc.
Dick Koepp
ONOGOLLY@aol.com
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