Challenge: How do you solve this?

[David M]

A wrench is enough to do that.

That would be my method as well.

[Pelagic]

Originally Posted by Zach

Could you take a big lump of steel or a magnet and swing it around the compass to see if it gets hung up anywhere?

I know my bucket of anchor chain will do the trick...

Right on the money Zach!

Note compass bearing (at dock) then with small magnet draw north point of compass card about 15* to the right. Repeat doing same to the left.

If the card in each case returns promptly to original heading it is free of mechanical type defects

[hellosailor]

Pelagic, you asked for answers not simple ones. Why do it the simple way (just loosen the compass from the binnacle and rotate it while eyeballing it. You might as well eyeball the entire thing, top and bottom, if you're checking it out.) when you can have a Chinese Fire Drill?

Or, haven't you ever heard of newbies being sent out to find a left-hand pipe wrench and a lubber line? [g]

Someone tried to send me for a left hand pipewrench once. When I brought back a blue one and a red one, and explained that as with many left hand items, the red one was designed for left hand, and the blue for right, there was little argument. Now, if I can just figure out where to find a snipe
So, Zach, looks like you are up.

[David M]

...or some relative bearing grease, a metric crescent wrench, the third leg to the deviation table, checkered paint, a bacon stretcher or 100 feet of waterline.

Still searching for the checkered paint But, I digress. Need a new challenge...

[David M]

Originally Posted by Kai Nui

Still searching for the checkered paint But, I digress. Need a new challenge...

That's great Kai Nui....you really did find one.

It is in my nature to take a smart ass approach to practical jokes
OK, here is a navigational question. You are heading from Long Beach Ca to Hawaii. The big island. What course do you need to maintain? (Show the math)

[David M]

A straight (as the crow flies) route and quickest route would be a great circle route which means you would change course as you go. Or do you mean a curved route with a constant heading as seen on a Mercator chart?

Good point. What I am after is the most direct route. If a cruise ship were to set a course, what would it be?
Hint, this is a set and drift excercise.

[David M]

I'm not sure I understand because a cruise ship would sail a great circle route which would take the ship the least amount of time and cost the least in fuel etc. This would mean a heading that changes between LA and Hawaii...unless they need to do some weather routing.

So to do a set and drift calculation, I need to know the speed of the ship and the set and drift of the ocean current to come up with a course to steer by. What is the speed of the ship? Ocean currents change all the time, so that would be difficult if not impossible to calculate....but you could always throw out a hypothetical vector for the ocean current. Wind causes some leeway on a ship as well....so I would need a vector for that.

Are you asking for the initial heading for the first leg of a great circle route when leaving the harbor in LA?

Sorry...I'm confused.

No apology necessary. Clearly the scenario was flawed. Let me change the scenario.
After you leave Long Beach Harbor, you set a course for Avalon on Catalina Island.
To answer the questions you have already asked, the windspeed is 15kts. Your SOG is 8kts.

[David M]

Sitting at home here today, I don't have a chart in front of me. So I cheated and went to Google Earth. Using my eyeballs only, it looks like a course of very roughly around 200 degrees true and 27 nautical miles from the outer breakwater at Long Beach. It would take 3.4 hours to get to Avalon from the breakwater. I don't know where a vector would fall into place. Does the boat have a COG different from its heading?

Yep. The real challenge is to see if anyone remembers how to calculate set and drift. Since GPS has become a standard, many of the traditional skills needed for navigation are being lost.