Interior of wooden motoryacht hulls

I am a recent graduate of Chapman's School of Seamanship Marine
Surveyor course. One of the things I was looking forward to learning
about was the treatment of rot in wooden hulls. The school didn't
spend much time on it because (and it's true) the majority of the
hulls I survey are FRP. But! I own two beautiful 35 foot wooden motor
yachts that I am restoring. I didn't want to do all this work and then
have things go wrong in the "basement". So, after months of study,
this is the treatment that I believe will keep these two old beauties
sound for another 15 years. After opening up the boat and installing
access to most of the interior of the hull, I pressure washed the
whole interior. Pumped the water out and let it dry. Then I boiled up
on the stove a mixture of antifreeze, boric acid, and borax. I spent
about $50 to make about 10 gallons, of which sells for around $90 a
gallon at the marine supply. The glycol in the antifreeze LOVES water
and absorbs into any wet surface, carrying the boric acid/ borax mix
into and wet or moist wood. Oils and epoxies will not go into damp
wood. Thinking it out, this is the only way I could think of to take a
strong anti-fungus to any wet parts. After drying it out (summertime)
I am now cooking boric acid into raw linseed oil and maybe getting a
little packets of anti fungus that the paint store sells to add also.
Fungus and rot LOVE linseed oil to eat. I am going to take this
mixture of raw linseed oil, paint thinner, and boric acid/anti-fungus
and spray it into the inside of the hull where the glycol/boric acid
mixture has already absorbed into the wood, sealing it in there for
all time. The last spraying will be with boiled linseed oil
substituted for the raw. Boiled doesn't absorb as much, but does leave
a final barrier.
I know this sounds like a lot of work. But it really isn't. I fill
industrial spray bottles from Costco with my mixture and it takes
about 3 minutes to empty each one. Once everything is in the spray
bottles , I just put on my gasmask and empty a couple into the wood
before I leave the boat for the day, or the week. It really doesn't
take any time at all.
I was going to paint the bilge and all the inside of the hull, but all
my studies showed me that it wasn't a good idea. Paint goes on the
outside of the boat to keep moisture out, and the inside of the boat
gets a treatment that lets moisture evaporate back out.

The whole cost of this for two 35 foot boats is about $100. These
boats are worth near $60,000 together. A small price for a little
peace of mind about wood rot.

Contact me if you would like my recipe's.

My next adventure is to see if the old cresote roofing tar that a
local roofing company gave me from the back of their warehouse can be
mixed with paint thinner and substituted for the pine tar sold by the
wooden boat companies!!!

Please let me know if there are any other folks out there that have
tried to preserve their classic boats on a budget!

Thats quite a chemical composition. I am not a chemist so I can not comment
on the compounds you describe but I do know a couple of things about rot.

One of the best ways to avoid rot in timber boats is to ensure adequate
ventilation throught the entire boat even when moored and with the covers
on. Yes proper ventilation is the key to longevity in timber boats not rot
treatment.

It would seem the composition you have described is aimed at killing the
fungus spores that cause and distribute dry rot. It seems like a lot of
trouble but I guess if it is a long term fix and you know it works... then
why not. Assuming you know the borax will remain active 15 years.

I am currently restoring an older timber launch and using CPES (clear
penetrating epoxy sealer) on any new or removed & replaced timber components
in the boat.

I am using polyurethane bedding compound in joints to keep water out and
round the deck etc. as it will seal and still remain flexable and move with
the wood rather than use epoxy "glue" which is not.

Here is the CPES Im using. It is very expensive though which is why Im not
doing the entire boat with it.

I do think you are right in painting and sealing the outside of the boat and
leaving the inside to "breathe" (take and give off moisture) I think this is
best practice. I have heard and seen photos of some horror stories where
wooden boats have been fibreglassed outside (sheathed) and epoxy coated
inside. Moisture laden wood does not like to be sealed.

I will add this. My project launch is about 60 years old and completely
original. Despite having 27 broken ribs only one is rotted and 2 planks need
scarfing in up the bow. Other than that it was a working boat and spent its
whole life moored.

It was painted outside hull and deck and the inside has never been painted.
Not even the bilges or engine beds.

Craig

"tomdownard" <Thomas.Percy.andDownard DeleteThis @gmail.com> wrote in message
news:1183303947.180208.16460@g37g2000prf.googlegroups.com...
>I am a recent graduate of Chapman's School of Seamanship Marine
> Surveyor course. One of the things I was looking forward to learning
> about was the treatment of rot in wooden hulls. The school didn't
> spend much time on it because (and it's true) the majority of the
> hulls I survey are FRP. But! I own two beautiful 35 foot wooden motor
> yachts that I am restoring. I didn't want to do all this work and then
> have things go wrong in the "basement". So, after months of study,
> this is the treatment that I believe will keep these two old beauties
> sound for another 15 years. After opening up the boat and installing
> access to most of the interior of the hull, I pressure washed the
> whole interior. Pumped the water out and let it dry. Then I boiled up
> on the stove a mixture of antifreeze, boric acid, and borax. I spent
> about $50 to make about 10 gallons, of which sells for around $90 a
> gallon at the marine supply. The glycol in the antifreeze LOVES water
> and absorbs into any wet surface, carrying the boric acid/ borax mix
> into and wet or moist wood. Oils and epoxies will not go into damp
> wood. Thinking it out, this is the only way I could think of to take a
> strong anti-fungus to any wet parts. After drying it out (summertime)
> I am now cooking boric acid into raw linseed oil and maybe getting a
> little packets of anti fungus that the paint store sells to add also.
> Fungus and rot LOVE linseed oil to eat. I am going to take this
> mixture of raw linseed oil, paint thinner, and boric acid/anti-fungus
> and spray it into the inside of the hull where the glycol/boric acid
> mixture has already absorbed into the wood, sealing it in there for
> all time. The last spraying will be with boiled linseed oil
> substituted for the raw. Boiled doesn't absorb as much, but does leave
> a final barrier.
> I know this sounds like a lot of work. But it really isn't. I fill
> industrial spray bottles from Costco with my mixture and it takes
> about 3 minutes to empty each one. Once everything is in the spray
> bottles , I just put on my gasmask and empty a couple into the wood
> before I leave the boat for the day, or the week. It really doesn't
> take any time at all.
> I was going to paint the bilge and all the inside of the hull, but all
> my studies showed me that it wasn't a good idea. Paint goes on the
> outside of the boat to keep moisture out, and the inside of the boat
> gets a treatment that lets moisture evaporate back out.
>
> The whole cost of this for two 35 foot boats is about $100. These
> boats are worth near $60,000 together. A small price for a little
> peace of mind about wood rot.
>
> Contact me if you would like my recipe's.
>
> My next adventure is to see if the old cresote roofing tar that a
> local roofing company gave me from the back of their warehouse can be
> mixed with paint thinner and substituted for the pine tar sold by the
> wooden boat companies!!!
>
> Please let me know if there are any other folks out there that have
> tried to preserve their classic boats on a budget!
>