I am trying to find any information I can on the benchmarks for our gyro and repeaters. The drawings for the ship (140) show them in one spot but they are not there. Is there a way to establish a new benchmark for them?

Are you sure they are not there? Look up close - there may be welds there that have been painted over w/o putting the contrasting color back on.

You can have new ones installed. They are not supposed to be painted over, rather bare metal. You should probably have them professionally aligned/surveyed if you end up installing a new set.

QM1 sends

We looked all over the bridge and the orig drawing shows the benchmark on the forward window frame but I will take a shot and say these are not the orig window frames. The gyro itself has notches in the mounting frame that should be the bench marks for it. The repeaters have some notches on the outer ring but we are not sure if they are the marks we are looking for. What are the bench marks actually for? what are you aligning with them?

Thanks for the help

The question of bench marks for the 140's came up last week on my cutter. Being that we have gyro repeaters on a roller rail, I don't see how a bench mark on the structure of the ship could be accurate.

ED3196499,

The bench marks are for aligning the repeaters on their mounts so when you are using an azmuth circle or alidade, the bearing you are looking at is precise. That's as easy as I can explain it.

Use To Be A QM sends.

If I remember correctly, the bench marks on the 270's aren't actually marks, but an apex of the superstructure itself. That point was still referred to as the benchmark, and used as such.
I'm not familiar with the 140', so I don't know if that's even possible for your boat.
I'd give a call to the CART guys... better safe than sorry.