There are two main types of rot that infect wooden boats.
Both are caused by fungi growing within the wood tissue.
Types of Rot.
is grows when unprotected timber is in constant contact with
Dry rot occurs when the unprotected timber has repeatedly been wetted
and then dried out.
However, the wood won’t rot just because it is wet but because the
rot fungi have the ideal conditions in which to grow.
They need moisture, oxygen, stable temperature and food in the form of
the wood fibers.
Given the right conditions they can grown and multiply rapidly.
However, even if the conditions change enough for the fungi to die out
their reproductive spores remain and become active if the right
Just like the dreaded teredo the fungi will take the easiest route
along the grain of the wood. It can also spread, via contact and
sometimes, the spores can travel through the air.
Boats are particularly vulnerable to both types of rot because of the
damp environment, though salty water does go some way to slowing it
Prevention is, as
they say, always better than a cure.
A neglected boat is the one
most likely to suffer from
So, regardless of how well you
have protected the wood a
little bit of time and care can save much work in the long run.
Keep her well ventilated even
when in storage or on her
mooring, make it a rule to check her every so often, open her up and
breeze to flow through, dry up any condensation and use a little white
to get rid of mildew.
don’t even think of
However, initially the surest
way to limit the danger of
wood rot is to ensure that all exposed timber is treated with an
There are numerous wood
treatment products available, my
own favorite is good old coal tar creosote.
It will depend on the type of
construction as to what you
can use, creosote being oily will not work with epoxy or some other
And there are regions such as
the European Union where
the sale of creosote is limited (health and safety bureaucrats worried
might drink it?).
The next stage in the armory
is a good coating of primer
and paint, the fungi won’t eat the wood if the spores can’t get
In many ways an all wooden
boat can be less prone to rot
than plastic boats.
Wooden boat owners tend to be
more aware of the problem
and take better care of their boats.
And many of the plastic
variety of boat are often built
with an untreated wooden frame work and wooden reinforcements, get a
the fiberglass and damp and rot will get in but not be seen until it is
Prevention is all about
understanding the nature of the
fungi and reducing its ability to flourish.
The reason archaeologists can
find extensive remains of
ancient wooden boat is because the fungi has been unable to thrive.
It may have been that the
timber has been lying in silt
which has reduced the oxygen supply or the water temperature has been
If the timbers are then
removed from that protective
environment and brought to the surface the archaeologists then hast to
other form of protection to stop any spores in the wood from bursting
Wood Rot Treatment.
If the worst has
come to the worst and you have found some wood rot there is only one
it out and replace it with new wood.
Don’t be tempted by the
products that promise to
restore rotten wood, they cannot rebuild the damaged structure and
the strength, of the timber.
But before you replace it you
need to kill off any wood
rot fungus and spores in the surrounding, apparently sound, timber.
The infection can exist well
beyond the obviously rotten
To treat this you will need a
fungicide, a toxic
substance to kill any fungi that may still be in the wood.
There are ready made products
available. Just check that
they kill the fungi and are not just preventative.
One inexpensive remedy is
ethylene glycol which is found
in the antifreeze used in cars.
This is toxic to most wood rot
organisms and will
penetrate quite deeply.
Or you could use a borate
solution, Sodium Octaborate
(Sodium Octaborate Tetrahydrate) can be bought either as a solution or
solid which is mixed with water.
Any white residue left by a
borate solution can be washed
off with water.
Wood treated with glycol or
borate can be finished or
glued once it has dried completely.
I am perfectly aware that the majority of Wooden Boat aficionados are sensible folk. However, I need to point out that I am an amateur wooden boat enthusiast simply writing in order to try to help other amateur wooden boat enthusiasts. And while I take every care to ensure that the information in DIY Wood Boat.com is correct, anyone acting on the information on this website does so at their own risk.