- A common myth that people will say is, oh,
there's only a little bit of water in there.
(light music)
In this video today, I'm gonna use a sample piece
of a transom so I can show you the thickness
of the layers and the different materials used
throughout the construction.
So, when a boat's laid up on the factory,
they'll have a mold.
And then in the mold, they'll start with the gelcoat
on the very bottom, and they'll put layers
of fiberglass matting and resin.
From there, it will depend on which areas need
the structural support, and that's where the timber gets put
on top and then fiber-glassed in to make it all one.
If it's not one, it's not gonna be structurally sound
because it's gonna have movement,
and that's gonna cause problems.
With this timber paste, you can see the first layer
is the gelcoat, which is about two millimeters this.
Then you've got the fiberglass layer and resin,
which is about five millimeters thick.
From there, you've got the timber coring,
approximately 45 millimeters thick.
And lastly, you've to the last layer of fiberglass
and resin, and then the flowcoat on top of that.
Some of the most common ways water can get
into a fiberglass core is when you introduce a screw.
So as you can see, that screw protrudes
past the fiberglass layer and into the timber core.
And water can start to track down the threads
if it's not sealed properly or the seal breaks loose.
Over time, that screw tends to corrode
and let more and more water in,
until eventually you've got a rotten timber core.
So, things like take decks screwed in to the timber coring,
that can cause rot in that area over time.
Another key phrase thrown around
in the industry is delamination,
which you might see on a survey report.
Now, delamination is when this fiberglass layer delaminates
from the timber layer,
or this layer of timer plywood delaminates
from the next layer.
If you've got these two coming away,
it's no longer one and it's no longer going
to be structurally sound.
So, the same principles hold true, for example stringers
and bulkheads are timer cored.
If you let water into a stringer,
the boat's had a partial submersion,
there's a screw hole there, water gets in, it can't get out.
You cause rot later down the track.
Boats with a tinder cored transom will either have
an outboard or a stern drive fitted.
A common myth that people will say is, oh,
there's only a little bit of water in there
so it doesn't matter.
Now, look that's fine if you don't put the boat
in the water and you don't use it.
But, as the boat gets used, goes through the normal stresses
of driving the boat, and have, you know,
large mechanical forces pushing and pulling
on the back of the boat.
And I thought it was worth mentioning
because not every single transom is actually timber cored.
So, depending on the drive of the boat,
so let's say a shaft drive for example,
they don't necessarily have timber coring at the transom
because they don't have a stern driving hanging
off the back of it.
And that's why it's so important to know,
firstly, if your transom is primed to be run.
So, if you've only got a fiberglass core,
fiberglass doesn't tend
to absorb the water like timber does.
Timber has a, you know, natural water content to start with.
And then once you get water in there,
that's when you cause rot.
It degrades and you have a major problem.
What happened on this particular piece was
it had a transom assembly mounted,
and the tiller arm comes through here.
Tiller arm's steering seal is here, and it leaked.
And what happened was it leaked into this section here
and the water was coming in,
tracking down through the timber,
and it caused this cracking down here.
So, luckily the rot hadn't spread to the outer areas
and this piece was the end of the rot.
Now, this particular piece is not
from Australian-built boat.
If they had've sealed this section properly
from the factory instead of drilled this out,
there would not have been a problem.
So, the transom,
I have seen transom assemblies leak quite regularly.
But, the timber coring still stays dry
because it's been sealed properly.
One thing I need you to do is tap the like
and subscribe button like a surveyor tapping
the bottom of your hull,
so we can continue to grow this channel.