Monday, June 19, 2023

All for a single screw

While poking around in the engine room a while ago it was noted that a bonding wire was just laying around loose in the bilge, bonded to nothing in particular. The screw that once connected it to the starboard side shaft seal housing had corroded to the point where it had lost its head. The rest of it had remained, fused into the metal part of the seal. There was no chance of extracting the broken-off screw bit with an easy-out. Worse, the odds were good for the easy-out breaking in the attempt. Those who have tried to get a broken easy-out out of whatever it had broken off in, are likely cringing at the very thought. I did. Another approach was needed.

One could drill and tap a new hole near the old one and put in a new screw. Not much of a project but still something that needed to be done before putting a lot of miles under the keel. Still, one should always be just a bit careful about drilling new holes in machinery. Particularly when that machinery is sitting in water and the hole is under the water line.

So out came the electric drill and drill set for making the new hole. Also needed was the tap & die set for threading the new hole. The electrical bag held some of the tools needed for making up a new bonding wire. The hydraulic crimper box came out to fix the ring connecters to the ends on a new piece of 6 aught wire. The general purpose tool set came out for odds and ends like screw drivers and pliers, along with some scotchbright and 80 grit sand paper for assuring good electrical bonding on the somewhat grungy parts. The parts boxes for screws, washers, connectors, and tie-wraps, were brought out from storage.


Since we were dealing with bonding wire there was no need for the heat gun box as heat shrink on the connectors is not required. For those wondering why not use the original wire, it broke off at the supposedly attached end as soon as it was tugged on just a little bit. Attaching that end at a much more accessible spot than the original meant installing a longer wire.

We opened up the access panels to the engine room and jumped in, both figuratively and literally, to get the job done. After deciding exactly where to poke a new hole, the drill motor was brought into play. The hole was safely drilled but there was no way to fit the normal “T” handle tap driver into the workspace. So the electric drill was called back into play to drive the tap into the new screw hole. A bit of soap made do for cutting oil while the lightest possible touch was applied to the drill trigger.  Electric  drills are excellent tap snappers. Which will ruin a day just as much as snapping off an easy-out.

It all went pretty much as planned, which means it took about twice as long at it seemed it should have. We did have to open yet another tool box for a magnetic pick-up tool. That was needed to chase down a runaway tap that bounced its way into the work space. As a long time aircraft mechanic, leaving stray parts or lost bits in a work space is simply intolerable. After the task itself was done, came putting all the tools away, a final cleaning up the work space, and closing up the access panels to the engine compartment. And all to replace a single screw. 

But that is the way of boats.




2 comments:

s/v Sionna said...

Another job well done. I so appreciate your approach to these issues: ie "let's do this right" instead of "Oh, that'll do..."
And as for the magnet for the dropped tap - yeah, that. My aircraft mech training takes me the same direction. Nicely done.

TJ said...

Thanks, it did work out pretty well. Our Diver told us the starboard side prop shaft zincs were wearing faster than the port side.. I don't know if that missing bond wire was the culprit, but it seems likely. Back when I was doing a lot of flying under ferry permits "Oh, that'll do" was kind of that standard one aimed at before limping off into the sky. Which led to some very, shall we say, "interesting" flights. At this point in life I try to avoid that kind of "interesting" as much as possible. If I had the time and the $$ I would go through First Light with a fine toothed comb, writing up everything as I would have during an acceptance flight on a new aircraft, and then hand the squawk list to the most reputable boat yard I could find to have it all made "right". But I'm guessing I wouldn't live long enough to see job completed. I'm not sure such a boat yard exists. And I could probably buy a new boat that was twice as big and would cost half the repair bill. To me a boat is as much a hobby as it is a way to live and travel on the water. Might as well do it as right as conditions will allow.