Again on the subject of sharing..
I know that I´m exposing that my restoring project
of a beautiful old boat
might have gone a bit too far but I will anyhow open my mouth just to shed the last pice of possible doubth......
12 years ago I was in the process of studying keels and attachments methods and materials and learned that it is almost impossible to cast a big keel
that is really fair and will fit your keel
sole perfectly. This is mainly due to uneven shrinking as it colds.
This was very evident to my fin keel.
The interest was partly due one of my old collegues that had a a rather extreme racer
produced that on the maiden voyage in really tough conditions on the Swedish Eastcoast lost
the keel. It was unfortunately very cold water
and my friend lost
his daughter that did not make it until they were rescued.
The architect was of course responsible fitting a high aspect racing
keel with a single
row of keel bolts
but other aspects interested me as well.
The normal procedure with mastic betwen keel and sole invites to a small movement in the construction wich in turn invites to acceleration loads on the bolts when beating in rough seas
It is easy to see that if you have a perfect fit the movement problem will be reduced as far as is possible and if you have the right amount of keelboalts with the correct preetension you will get no acceleration loads due keel movement.
I contacted one of the companies that are into keel manufacturing and learned that the only good way to approach the perfect fit wish was to saw the lead keel with a chainsaw. They said you can not saw lead in any other way since it will just clog.
The problem was now just to get a chainsaw and make some guides so it could be used for precision sawing.
Making the guides fitting for normal L shaped steel
that was easily screwed into the keel was really very easy. A rather uneventfull 3 meter run with the chainsaw and there was a perfectly straight plane surface of lead.
I lost 1,5 cm of lead but belived that that was OK.
I was at that time studying a West Epoxy
instruction book on boatbuilding and also SP´s technical manual on Epoxy
Due to my wish to achive the absolutely best keel attachment that is possible I contacted West Epoxy´s technical director to discuss weather
or not to use Epoxy with high strength additive instead of the usual mastic between lead and fiberglass
He said it is no better way to attach the keel but you have one downside and that is you will never get that keel of the boat
if so needed.
I did of course go just that way and I conforted myself in that I hope to find one way to get the keel of the boat if ever needed without breaking anything.
The procedure is just like if you are using mastic with the only difference that I used a single
layer of Mat and slow hardening epoxy with a thickener giving the highest bonding properties.
While thinking about all that now rather a long time ago when I yesterday was writing about Microwaves and drying a wet deck core
an Idea struck me. This type of epoxys heat deflection temperature ( when it starts to go soft) is only 80 degres celsius. Putting the Boats lower parts
in a really hot bath for a few hours before lifting her out and removing the keel could probably do the trick.
Do I need to say I used 10 (25mm) highly polished keel bolts
that was screwed down with a compressed air wrench for lorries.
I do never worry about my keel ever poluting the seabed unattached form the reat of the boat.