This week I meet a major problem. The keel bolts are nearly all in place when something goes horribly wrong. Before that, I carry out an easy repair to my Ipotools inverter welder. I then discuss galvanic corrosion and material choices for keel bolts, and Hazel does a bit of work on her anchor chain box.

This is the story of the building of a Jay Benford designed, 31.8ft, junk schooner-rigged cruising sailboat. The videos are a week-by-week record of the build as it progresses and aim to show as much detail as possible of the various aspects of the build.

These videos take a lot of time and effort to make, in what is already a time-intensive project. Your support in watching, subscribing and sharing these videos is very much appreciated. You make a real difference!!

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Music tracks "Sit and Wonder", "Ocean View" and "The Great Divide" available on iTunes, Amazon etc. EP "Shake a Leg", album "Out of the Moloch", single "Ocean View".

Check out Hazel's music at https://music.apple.com/us/album/1503250522?app=itunes

Music from these videos is available from: https://ynotb.bandcamp.com/album/the-sv-tapatya-tracks

Thank you :-)

Tony

Closed Captions (CC):

0:07
[Music]
0:23
this is
0:25
[Music]
0:49
hello i'm tony this is s v to patch out
0:52
we're building this cruising sailboat
0:55
and this
0:56
starting to look quite nice down below
0:58
got the cushions up in the v-berth as
1:00
you may notice
1:02
so actually all the upholstery is
1:04
finished now which is
1:06
a very nice situation to be in and down
1:08
below we're getting very very close one
1:10
start this week that's a major major
1:13
thing i think a major thing coming up
1:15
this week
1:16
a problem that really is very very ugly
1:19
head
1:20
i shall attempt to explain the problem
1:23
uh why it happened how it happened
1:26
and my solution to it and
1:29
it's quite possible that my solution to
1:31
the problem won't be
1:33
to everybody's liking but
1:35
certainly to mine in here
1:38
um but we start off you remember last
1:40
week
1:41
i was fitting keel bolts into the into
1:44
the steel keel box
1:46
um
1:48
and i had i had a couple in place i
1:51
think at the end of last week so clearly
1:53
the first job was to was to continue
1:56
fitting those bolts
2:18
oh
2:29
so
2:48
it's
2:50
before we get to that big problem
2:53
we're gonna get there guys we're going
2:55
to get there
2:56
uh before we there was a small
2:59
small issue this week tiny issue
3:03
several people have asked me about this
3:04
this
3:05
hypo tools inverter welder
3:08
which is i'm really really happy with
3:10
great little tool
3:12
it doesn't weigh very much i'm going to
3:15
guess i don't know a couple of kilos i'm
3:17
guessing
3:18
and i guess one of the problems with
3:20
that
3:21
is that
3:22
it hasn't got much
3:25
much weight about it
3:26
so
3:27
[Music]
3:29
so what happened of course was that at
3:31
some stage i managed to get my foot
3:32
tangled in the electricity lead running
3:35
up to it
3:36
dragged it off the bench and it fell on
3:38
the floor
3:40
um and that
3:42
well afterwards it was making the
3:44
dreadful noise
3:45
and it was fairly obvious that in the
3:47
back here we've got a cooling fan
3:50
it's fairly obvious that the cooling fan
3:52
had broken
3:53
and for a while it made an awful noise
3:56
and then it started
3:57
running
3:58
intermittently well i went on the
4:00
website for the company seems to be a
4:02
german company
4:04
and uh they offer a
4:07
five year or seven i think it's a seven
4:09
year guarantee it's a good guarantee
4:11
they offer on it anyhow
4:13
and i contacted them and they were great
4:14
they they said yeah no problem you know
4:16
send it back
4:18
we'll repair it or send you a new one
4:21
you know marvellous marvellous
4:23
but
4:25
oh
4:26
i felt guilty let's be honest it was my
4:28
fault there's no reason why they should
4:30
give me a new one is it completely my
4:33
fault so
4:34
i looked into it
4:36
and i found you know it's just a little
4:38
80 centimeter square
4:41
fan and they're readily available you
4:43
get my amazon so i just found one that
4:45
was the closest closest ampage to the
4:48
old one
4:49
and uh swapped it out
4:51
here's the
4:52
old one here
4:54
there's the old one and you can probably
4:56
see at the top there you can see it a
4:58
couple of two two
5:00
fan blades have broken off
5:02
um but piece of cake swap it and uh it's
5:06
working fine again now
5:07
cost under 10 euro for the fan
5:11
and i feel
5:12
more honest having done it myself
5:15
works great i've welded quite a lot with
5:16
it since fan runs evenly now keeps it
5:19
nice and cool so
5:21
that was a good one
5:24
so i managed to drop my welder
5:28
and broke the fan
5:44
uh
6:01
[Applause]
6:04
it's not thick
6:19
[Applause]
6:28
okay
6:57
um
7:10
so
7:22
[Applause]
7:27
pretty good
7:36
um
7:53
[Applause]
8:18
[Music]
8:32
so
8:46
but as you may notice i was missing a
8:49
couple and i had to go back
8:51
i found
8:52
the bronze rod that i ordered and i had
8:55
to order a couple more i was missing a
8:56
couple because i decided to double up
8:59
some of those keel bolts i wasn't the
9:01
original the design has all the kill
9:03
bolts singular in one line
9:06
and i wasn't happy with that i wanted
9:07
some doubles
9:09
uh spread the loads a bit
9:11
more to my liking so i went back ordered
9:14
some more bronze and it arrived
9:16
and uh
9:18
it was time then to to get that in place
9:21
machine it and prepare it
9:23
and fit them
9:44
[Applause]
10:31
so it's time to come to this week's big
10:35
problem
10:36
and the solution as i see it and some
10:39
theory and some thoughts and and and and
10:44
it started so
10:46
and it was now in the very nice position
10:49
of having all of the bronze bolts
10:51
machined
10:53
and uh
10:54
fitting
10:55
but one of the new bolts wasn't quite
10:58
upright no this was sitting at a bit of
11:00
an angle
11:01
so um i did what i i'd actually done to
11:05
a couple of the older bolts as well when
11:06
they weren't quite in line i gave a good
11:09
old shove
11:10
although i have to say this wasn't a
11:12
shove with my full force
11:15
but i gave it a shove to line it up
11:17
straighten it up
11:19
and it broke i thought well
11:22
that's not very good
11:24
so i
11:25
managed to extract the broken end it
11:27
broke off this
11:29
there's the end there hey that's the end
11:32
there just broke off
11:33
so the threaded
11:35
section there was was screwed into the
11:37
into the long nut and it broke off at
11:39
the top of the
11:40
thread well i extracted that use the
11:43
stud extractor got it out
11:45
swapped it for one of the other new
11:47
pieces of bronze screwed that in there
11:49
and
11:50
it was also not quite give it a shove it
11:53
broke
11:54
it broke quite easily
11:57
quite easily now i have to say
12:01
i bought this the second batch of bronze
12:04
i bought was the same
12:06
material
12:09
i was careful about that same material
12:10
as the first batch but several of the
12:13
first batch i'd lined up without any
12:16
issue
12:17
so
12:18
it's the first thought and i've got many
12:20
many thoughts i'm going to attempt to
12:21
share with you here
12:23
um bronze obviously bronzes and bronzer
12:26
are all sorts of alloys and
12:30
we live in a very simple world where we
12:32
call something you know silicon bronze
12:34
or phosphor bronze or aluminium bronze
12:37
but there's that doesn't reflect
12:39
the reality there
12:41
in fact there are loads of different
12:42
alloys of each of those categories
12:45
um
12:46
[Music]
12:47
and the other issue
12:49
i now believe
12:50
is temper
12:52
so each of those
12:54
bronze pieces or any bronze piece can be
12:56
heat treated and that changes its
12:58
material properties
13:00
and i think what's happened is is that
13:02
the second batch of bronze i bought had
13:05
a different temper different heat
13:07
treatment to the first batch and and
13:11
well
13:12
it's basically no good if i can break it
13:15
with with just you know the medium
13:18
strength
13:19
it's not good enough i cannot possibly
13:21
live with having that as my kill bolts
13:24
and it in turn made me doubt the whole
13:28
lot so
13:30
the bronze i've used i'm going to talk
13:31
about the bronze i've used in a minute
13:33
but i can't go to sea in a situation
13:36
where i don't trust my kill bolts and
13:38
even though they're brand new bronze
13:41
uh
13:42
to the dimensions that the designer
13:44
recommended plus i've increased the
13:47
number of kill bolts i still can't go to
13:49
see
13:50
with them
13:51
with bronzer i don't with bolts that i
13:53
don't trust
14:10
so
14:24
so
14:40
[Music]
14:43
so
14:44
bronze
14:45
when you read up now i and i have read
14:48
up an awful lot i've been reading about
14:50
kill bolts for years you know on and off
14:53
obviously
14:54
and i've read up an awful lot and
14:56
there's a lot of opinion out there
14:59
um
15:00
which is
15:01
that
15:03
um
15:04
when you read up obviously everybody
15:06
says um silicon bronze
15:08
everybody say or aluminium bronzers too
15:12
as i've already mentioned
15:14
you know there are various different
15:15
alloys of those things and and
15:18
you have to try and find those materials
15:20
available as well
15:22
silicon bronze here in germany silicon
15:24
bronze
15:25
is fairly hard to find you can buy a
15:28
silicon bronze threaded rod although as
15:30
i speak at the moment i know that the
15:34
the most common suppliers out of stock
15:36
of it but um
15:38
you can buy a silicone bronze threaded
15:40
rod it is mighty expensive 5 8 unc
15:44
silicon
15:45
rod three feet long goes up over 150
15:48
euro
15:49
a length
15:50
mighty expensive
15:53
so what i did was i looked around for
15:55
alternatives
15:57
and uh you know i've learned along the
15:59
way clearly but um
16:01
this week i've learned an awful lot
16:04
but um
16:05
you find bronze
16:07
resistant to
16:09
marine environments no problem phosphor
16:12
bronze rod is much
16:14
cheaper
16:15
which is i use phosphor bronzer
16:18
much cheaper marine environment
16:20
resistant it's tensile strength the
16:24
ultimate and yield tensile strength are
16:26
comparable to phospho two silicon bronze
16:31
let me say this
16:33
coming back a step
16:35
even in silicon bronze there is a wide
16:38
range of
16:40
tensile strengths i think
16:42
i think and i'm doing this from memory i
16:44
haven't got the numbers in front of me
16:45
but i think it ranges from
16:47
105 megapascals to
16:50
450. that is an enormous range of
16:54
tensile strength in in silicon bronze so
16:57
just simply saying you need silicon
16:59
bronze this is nonsense
17:01
this is nonsense and how is the lay
17:03
person supposed to know this
17:06
so
17:06
i use fossil bronze as i say the bronze
17:08
rods that you saw me using the tensile
17:11
strength was within
17:12
comfortably within the silicone bronze
17:15
tensile strength range it's let's say
17:18
marine environment resistant the
17:20
phosphor makes the bronze a bit stiffer
17:23
i believe
17:26
so
17:27
that's the claim obviously the fact that
17:29
i can
17:30
bend it and break it but i can break it
17:32
with a bending movement
17:34
if you think about what happens in a
17:36
bend the outside of that bend is in is
17:39
in tension
17:40
and the inside's in compression the
17:42
middle is probably in shear why isn't
17:43
she
17:44
you've got those three combination
17:45
forces i've broken it well below its
17:48
tensile strength well
17:51
i believe
17:53
not good enough
17:57
talking about kill bolts
17:59
people basically shout out you know
18:01
silicon bronze or mono
18:04
this is the standard standard retort
18:07
isn't it when somebody mentions kill
18:09
bots
18:11
what we have to do in practice is get a
18:13
bit scientific about it
18:16
and if you think about what i was doing
18:18
there i've got the steel box i've got
18:20
the lead ballast i've got the bronze
18:23
kill box i was a bit uncomfortable with
18:25
having three materials
18:27
let's not kid ourselves
18:28
and i read up quite a bit on on galvanic
18:31
corrosion or
18:33
and whatever
18:35
and
18:36
i thought it would be fine so it leads
18:38
to the question of what am i gonna do
18:40
about it what i'm i
18:43
i think the first batch of problems i
18:45
bought is probably good i say i've given
18:48
that the same amount of bending force
18:50
and
18:51
it's all been good
18:52
but bronze is expensive and i'm
18:56
that i think it's good enough isn't good
18:58
enough
18:59
you know and i'm not prepared to risk
19:02
buying another four or five links of
19:04
bronze and haven't find out they're just
19:06
as bad at the price of bronze
19:09
um so i'm not gonna do that
19:11
so
19:12
i've gone back to
19:14
investigating materials
19:16
when you read up on on you know the
19:18
common materials for for kill bolts are
19:20
bronze
19:22
people always say monel but actually
19:24
find an example of a manufacturer that
19:25
uses money literacy you know you are not
19:28
going to find one
19:29
silicon bronze stainless 316 stainless
19:32
passive
19:34
or mild still quick bit of theory i try
19:37
not to get too carried away here
19:39
um galvanic corrosion which is the
19:42
corrosion that happens in a sea water
19:45
environment or
19:47
between
19:49
two differing metals
19:51
so basically if you've got two different
19:52
two or more different metals plus an
19:54
electrolyte and sea water is an
19:56
electromagnet you get galvanic corrosion
19:59
we need to look at
20:01
what all of all of the science tells you
20:03
that you need to look at the anodic
20:06
index value of the metals and keep them
20:09
as close as possible to keep galvanic
20:12
corrosion to a minimum and they tell us
20:14
that the
20:15
we need to keep the difference of the
20:17
anodic index value difference below uh
20:21
0.15 volts
20:24
for uh for things to be
20:26
happy in a seawater environment
20:31
that's all well and good the problem is
20:33
the next problem is when you start to
20:36
look at anodic index tables
20:39
there are different ones out there
20:41
and i have looked and
20:43
what we have to do again
20:45
you know we have to
20:47
read and we have to try and find sources
20:50
that are credible
20:52
and i have found two completely
20:54
different tables of anal anodic index
20:57
values
20:58
one seems to be based on a study
21:01
published by i suspect the american u.s
21:04
american army military
21:08
and one
21:09
is published
21:11
in a paper from
21:13
published by the university of maryland
21:16
i believe
21:18
and the numbers in them are wildly
21:21
different
21:22
wow significantly different put it that
21:24
way
21:25
and they're both good sources on there
21:27
and which one do you believe
21:30
well the one that's referenced on
21:32
wikipedia and the wikipedia article on
21:34
galvanic corrosion is
21:36
is good as far as i can tell it it
21:38
doesn't contradict anything else that's
21:40
out there
21:41
um but the table published on wikipedia
21:43
is the one that comes from the us
21:45
military or at least i think comes with
21:46
u.s military
21:48
um and those values are what
21:52
so why look at that table
21:54
what we see is we see bronze at
21:58
0.4 volts
22:00
laid at
22:02
0.7 and straight away you see that
22:05
bronze and led are going through a volt
22:07
apart which is too much actually
22:10
which is curious since everybody says
22:12
bronze bolts with leg kills but anyhow
22:14
went through the vault apart
22:17
and steals regular steels at
22:21
0.85 volts
22:25
and you're already there i hope
22:28
regular steel and lead are 0.15 volt
22:31
apart
22:32
within the optimal range
22:36
for
22:37
for
22:39
minimizing galvanic corrosion
22:42
they say that
22:43
up to 0.15
22:45
volt apart you don't need to worry about
22:47
galvanic corrosion
22:50
so that's what i'm doing guys i'm going
22:52
to use mild steel bolts
22:54
and
22:55
yes you might be crying out you're mad
22:58
possibly but weirdly years ago in
23:01
when i first started this build i wrote
23:03
to another
23:04
well-known benford dory
23:07
builder and asked him what material he
23:10
used for his kill bolts and his response
23:12
was
23:13
miles still
23:16
well my last thoughts on this topic are
23:18
these
23:20
one thing that's important is that the
23:22
higher the number in that table or the
23:24
the the metal that is the higher number
23:27
in that table is the one that will be
23:29
corroded so if we take the example of
23:32
bronze and lead
23:34
it's the
23:35
lead that will be corroded
23:37
another thing you have to bear in mind
23:39
is that
23:41
that corrosion is also influenced by the
23:43
quantity of the material so if the
23:46
bronze is corroding the lead
23:48
to keep it simple but the bronze has a
23:50
very very
23:52
low mass compared to the mass of the
23:54
lead then you won't get much corrosion
23:56
so actually bronze bolts and leg kill do
23:58
work
24:00
the other way around using steel bolts
24:02
and lead kill of course the steel will
24:04
be
24:05
the higher number it's the one that will
24:07
be corroded and you've got a much larger
24:09
mass of lead so
24:11
it is
24:12
you know potentially problematic
24:14
although i repeat the voltage
24:16
differences
24:17
is one
24:19
0.15 volts which is
24:21
said to be
24:23
fine in a sea water environment
24:26
higher numbers okay in less harsh
24:28
conditions but even in seawater
24:30
environment that's a fine number should
24:32
be good
24:35
and the other thing
24:36
to bear in mind this is all only
24:38
relevant
24:40
if an electrolyte is present if you can
24:42
see all the seawater out no issue and
24:45
that's what i'll be trying to do
24:46
certainly i'll be
24:48
covering the entire thing in epoxy the
24:51
bolts the
24:52
steel keel everything will be painted
24:55
with a with a zinc
24:57
rich epoxy sealer and then epoxy primer
25:00
sealer after that so i'll be sealing
25:02
things thoroughly there'll be an epoxy
25:06
bog between the the keel ballast keel
25:09
and the wood the wood's all completely
25:11
kept encapsulated in in glass and the
25:14
boxes i'll say so
25:15
the goal is to keep the sea order out as
25:17
best possible plus of course the one
25:20
last thing
25:21
is that um zinc
25:23
has an
25:24
anodic index of
25:26
1.25 volts
25:28
so by strapping a couple of zinc anodes
25:32
onto the outside of the steel kiln
25:34
the zinc will protect absolutely
25:37
everything
25:38
the zinc obviously gets eaten away first
25:40
and as long as you don't let all the
25:42
zinc get in the way it's protecting all
25:44
the steel work
25:46
and if the steel
25:47
bolts
25:49
are
25:50
connected
25:52
uh to the steel box and to the zinc
25:55
then the zinc anode sacrificial anode
25:57
will protect
25:59
absolutely everything and that's their
26:01
job isn't it
26:05
doesn't matter if i make the stroke too
26:08
no
26:09
just waste a bit of epoxy that's all but
26:12
what are you doing here hazel i'm
26:14
unboxing my uh
26:17
anchor box yeah anchor chain box oh yeah
26:20
yeah or just taping the corners
26:23
yeah
26:26
yeah that's good come back and watch
26:28
have a look at that in a little while
26:29
see how you're getting on
26:42
and that's it for this week thanks for
26:43
watching thanks for listening
26:46
um we've been pushing on
26:48
i've got the solar controllers um and
26:52
some some wiring to do should be getting
26:54
on with that soon i'm also making a
26:57
start on the smelting pot for the lead
27:00
and certainly hope to be pouring lead
27:03
very soon we're getting there
27:05
maybe even
27:06
well
27:07
in the next couple of weeks i hope to be
27:09
pouring lead so
27:11
as i say thanks for watching still
27:13
thumbs up
27:15
hit that subscribe button please
27:17
and
27:19
massive thank you to everybody who
27:20
supports us on patreon paypal
27:23
if you'd like to support the project
27:26
get over to the patreon site link coming
27:28
up
27:30
see you later bye
27:42
[Music]
27:57
ah
28:03
uh
28:04
[Music]
28:11
[Applause]
28:11
[Music]
28:17
[Applause]
28:20
is
28:22
[Music]