One of my jobs in the navy was to poure the terminals for the CDP's
(cross deck pennants).

tools are easy to get or fabricate, the whatch outs are.
1:Improper broom (the cone of wire you will be inserting into the
terminal)
2:wire touching the sides of the terminal (creates shadows)

3: Any oil in the broom (makes spelter explode)
4irt or loose stuff in the broom may cause inproper adherance of
spelter and wire)

5:terminal not heated to temp (can make bond between spelter and
terminal fail.)
6: to much Flux in terminal and broom (has some randome effects like
blowback and none adhearance)

the only tool you may have to look for is a dyno. not sure if you
would need one for a sail boat because i dont think the wire is under
all that much tension but you might. the pull out limit for CDP's is
80.000ths on 15 strands max.

method is prep terminal (grit blast the internal surfaces and rinse
with a fast evap non film forming cleaning solution)
slip over wire.
broom wire and clean well (same as above)
lighty spray with flux
slide terminal over broom
adjust wires in terminal to remove shadows
(did i mention no oil in the whole thing this includes skin oil so
wear gloves and change them often)
Wrap terminal base with plaster tape (do a really good job here or
you will get burned boots)
wrap a plug top at least 1/2" over the teminal wall (this is important
somtimes you break a wire and it is a bit short you want all the wires
to protrude beyond the terminal lip)
start crucible and begin to melt the spelter for zink it is 900 or so
degrees make sure it does not go over.
heat terminal (heat crayons can be purchased at a welding supply for
900 degrees and you simply heat till the crayon runs)
when all is to temp pour (keep the speed of pour consistant and have
some one with a stick lightly tap the sides of the terminal so you
remove all the bubbles)
keep heat on the terminal for a moment (900 degrees for 3 and 1/2 min.
this part will bring up anything you missed in the cleaning and give
you some time to remove the bubbles)

when the zink is set let it cool till you can handle it by hand.
unwrap clean it with a wire wheel. cut the plug 1/8 inch from socket
lip (if you cant cut this close give it a bit more room. a band saw
works very well)
now comes the fun part grind the plug smooth and slightly domed (the
center of the dome should be 1/16th proud)
inspect for adheasion. pull test the terminal and look for pullout.

in 800 pours i had one fail the pull test.