It's what you learn after you know it all that matters.

[M. R. Bober]

I've been maintaining Cape Dorys for nearly 40 years and have become familiar with many of the finer points of these beautiful little ships. I've worked in more than a few boatyards and have learned how to troubleshoot and repair many problems. I can't do much about the aches & pains associated with accessing seacocks, but I've learned to pace myself.

After several days of grief, I resolved this problem, but wondered if any of my fellow DIYers would like to take a stab at it.
Here are the conditions and symptoms:
STARVIEW is on the hard.
It was connected to shore power with a heavy duty extension cord through an adapter to the ship's AC inlet.
On the first day the breaker at yard's receptacle (GFCI) tripped after about an hour. I moved my extension cord to another (non-GFCI) breaker and continued to work without interruption.
On the second day the main AC breaker (30A) on the boat tripped after a few hours the battery charger and AC outlets were energized at the time. I tried repeatedly to reset the breaker, but it tripped as soon as I energized either the battery charger or AC outlets (a drop light was connected and in the ON position. The light on the panel that indicates AC power would not light until the main breaker was energized.
I bypassed the ship's circuitry and connected the drop light directly to the extension cord. It worked and did not trip the yard's breaker.
Using a V-O-M I verified connectivity between the main breaker and those of the charger and outlets, but noticed some brown crud where the ring connectors attached to the main breaker. I removed, cleaned, and reconnected all of the AC contacts. Reconnected to shore power and everything was perfect!
The next day the ship's main breaker tripped instantly when I energized either the charger or the outlets.
The problem is resolved.

Any takers?

Mitchell Bober
Sunny Lancaster, (Where I'm positive all things can be resolved.) VA

[M. R. Bober]

No takers? I'm tempted to give a hint, but will wait.

Mitchell Bober
Sunny Lancaster, (Where last week was better for bottom painting than this week.) VA

[tjr818]

How about a shorted wire to the charger? When you moved the wire to clean the terminals everything was okay, until the wire settled back into the shorted position.

[M. R. Bober]

Nope. The charger is fine as are its connections.

Mitchell Bober
Sunny Lancaster, (ibid) VA

[tjr818]

What is the boat in the neighboring slip doing during all of this?

[M. R. Bober]

What is the boat in the neighboring slip doing during all of this?

The boat is on the hard.

Mitchell Bober
Sunny Lancaster, (ibid) VA

[Sea Hunt Video]

Upon further inspection of the main breaker you observed that it said "assembled in Pyongyang, North Korea from parts sourced in Beijing, China" printed in tiny 4 pt. font. You replaced the main breaker with one labeled "Made in USA from parts sourced in USA" proudly printed in 12 pt. font. Now, all works well.

[Paul D.]

A ground fault or loose connection between charger and batteries or within one of the outlet circuits?

[M. R. Bober]

Upon further inspection of the main breaker you observed that it said "assembled in Pyongyang, North Korea from parts sourced in Beijing, China" printed in tiny 4 pt. font. You replaced the main breaker with one labeled "Made in USA from parts sourced in USA" proudly printed in 12 pt. font. Now, all works well.

The main breaker was suspect, but proved to be fine.

Mitchell Bober
Sunny Lancaster, (ibid) VA

[M. R. Bober]

A ground fault or loose connection between charger and batteries or within one of the outlet circuits?

I thought the problem was a ground fault because the problem resolved (temporarily) when I connected to a non-GFCI receptacle. However there was neither a ground fault nor any loose connections.

Mitchell Bober
Sunny Lancaster, (ibid) VA

[swhfire21]

High resistance of dirty/loose connections caused heating and warmed breaker enough to trip it.

Close?

[M. R. Bober]

High resistance of dirty/loose connections caused heating and warmed breaker enough to trip it.

Close?

Well, that's what I thought when I cleaned the brown crud from the contacts and service was restored. HOWEVER the next day STARVIEW's main breaker tripped, repeatedly.

You are on the right track.

Mitchell Bober
Sunny Lancaster, (ibid) VA

[Stan W.]

I don't know that it explains everything but some of it could be due to reversed polarity at the yard's AC outlet.

[M. R. Bober]

I don't know that it explains everything but some of it could be due to reversed polarity at the yard's AC outlet.

Polarity was fine.

Mitchell Bober
Sunny Lancaster, (ibid) VA

[bottomscraper]

The light on the panel that indicates AC power would not light until the main breaker was energized.

Assuming the boat is wired as shown in the manual, the only way I can think of that would cause this is an open neutral. The power pilot light is connected to the line side of the main breaker. It should light when plugged in with the breaker off. If it doesn't, but does light when the the breaker is turned on it appears that the light is now getting it's "neutral" via the ground (green) wire rather than the real (white) neutral.