comes a time with every vintage wood boat when normal bottom
maintenance is no
longer sufficient to keep the water out.
Classic wooden runabouts can even be improved with the use of modern
materials such as waterproof membrains, plywood and bedding compounds
without detracting from
style or value.
Vintage wood boat Problems.
Many of the problems with vintage wood boat motorboats and runabouts
stem from planking a typical hard chine, concave bottom.
While this bottom profile is ideal for fast motoring, it isn’t
the ideal shape for wooden planks.
Fast motoring also means that the most concave area takes most of the
As a result
loosened, broken, or bent, planks crack along the fastener lines,
and chines get pushed out. frames
And that is as well as the rot which comes from water settling the
bilges and the transom area.
Then there are those boats where the layer of canvas between the inner
and outer planking is beginning to rot.
Wood is a wonderful material and there is nothing to compare with a
vintage wooed boat.
However, wood is always moving as it expands and contracts with the
changes in temperature and moisture levels.
Traditional boat building methods allowed for this movement as well as
Unfortunately, many of these boats have been damaged by repairs.
In some cases over
has put too much
strain on the fastenings and frames, and all too often hard inflexible caulking
products have been used.
a time when ‘fixes’ will no longer be sufficient to restore your
vintage wood boat and make her water tight.
And the ‘fixes can sometimes
result in even worse
This is when that leaky
vintage wood boat bottom will
have to be replaced.
So bite the bullet and remove
the old bottom.
You will now be able to see
and repair any damaged frames
or chines and tighten or replace the frame fastenings and don’t forget
give them a good sealing with paint.
Once that is done, before
re-planking give her bottom a
lining of either
plywood or a flexible waterproof membrain.
compound such as
fasten to the frames with either small
silicon bronze gripfast
nails or stainless staples.
Now the planking can be
replaced with a good layer of
flexible bedding compound between it and the
or the membrain.
If you have been able to save
most of the original
planking you may need to plane it down to compensate for the thickness
But even if you are planing to
replace all the planking
keep the old ones to use as templates.
Bed each plank as you fit it
and use silicon bronze
Excess bedding can be allowed
to ooze up between the
planks then scraped off and smoothed.
If you replace the inner
planking with plywood
it should be painted before
fitting and it can also be scored so that it looks like the
This process effectively
produces a double planked bottom
with the added advantage of the unidirectional strength of the
Don’t forget to check and if
necessary to repair or
replace the lower chine and lower transom planks.
Cold moulded Bottom.
An alternative to the planked bottom
would be to replace it completely
with a cold molded
Purists might argue that this
is perhaps too far from the
original vintage wood boat.
However, it will give her an
incredibly strong, seamless
This process is similar to
that above, except that
instead of finishing off with a layer of solid timber planks several
plywood are laminated together using that flexible bedding compound and
fastened to the frames using silicon bronze fasteners.
Use three to five layers of
the thickness of the original bottom. 4mm marine
As with the previous method
all the structural elements
should be inspected and repaired before replacing the bottom with new
It should go
without saying that while you have her stripped down all those other
components such as rudder assemblies, propeller shafts etc should be
Once the bedding compound has
properly cured the bottom
can then be sealed, primed, and painted.
This is not an easy fix, it is
a major undertaking which
will require a lot of hard, messy, time consuming work.
However, once done your
vintage wood boat will have a
bottom that will not leak for a long time to come.
And it will have the added
benefit that she will not have
to ‘take up’ every time you launch her.
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