All in all, the test on KH- 350
"Persistence" went well. As planned, we didn't launch, but tested while
still tethered to the trailer. It floated off the deck a few inches but
couldn't go anywhere.
We have the trailer workings and getting it
in the water smooth. It takes a bit of time to unhook, add in the
extension rod and then rehook, but not bad. After that, it's not much
different from launching any other boat. It was a little strange
standing up with my head out of the conning tower while the sub pitched
and rolling around me. Strange because for three years I've been in
and out of it while it was sitting on the shop floor and it didn't move a bit.
We put it in very slowly, watching all around as
we proceeded. The first problem we encountered was air leaking from
every bolt that passed through the forward and rear Main Ballast Tanks.
I have a bumper / hand rail running around the sides of it and never gave a
thought to sealing around each bolt that passed through. I also had a
few bubbles coming from the seal where the forward MBT mates to the
hull. All this can be fixed with a few dabs of
silicone. Those were the only leaks. As far as I could tell
in the hour it was in the water, there were no water leaks. It has been
so long since I put in some of the thruhulls that I wasn't positive I did the
final assembly with the O-rings in place on all of them. Guess I
did!
The main reason for the wet test was to run the
thrusters in water. When I was purchasing the props, the prop supplier
told me that they are a bit over sized but they are the nearest they have to
fit my needs. The only way to know how well they matched was to test in
water and monitor the amperage draw of the motors. I barrowed a heavy
amp meter used to check automobile starting systems and had it in the sub
while testing. They were right! My side thrusters are supposed to draw
20 amps and they drew 30. My rear thruster is suppose to draw 70 amps
and it drew 110.
In the process of testing the rear thruster I
smoked two power transistors on the motor controller but just
happen to have two good ones from the last controller I smoked while I
unknowingly reversed the polarity. Never throw away junk!
I played around with the sonar / fish finder and
the air system and all worked well there.
All in all the test was good. The thruster
results were expected and now I will build a jig to reduce the pitch on the
props and also mill them down a little. After that I will borrow the amp
meter and retest to see how close I come to the proper current draw.
Still on for a launch on June 6th.
Dan
H.