Hog and Sag surveys

What did you just ask?

Yeah....I know...kind of a dumb post but, the purpose of the survey was to see how much the deck changed in water compared to in drydock..

I guess I better put the vest on for this one...:)

Ships either hog (bow upwards in the middle) or sag (the opposite) when floating is what I think he said. I would like to know how it is done on an unstable platform (even a little bit)?

The first 6 frigates in the US Navy (USS Constitution is one) where intentionally designed to be stiffer to minimize hog and sag. Excessive hog or sag adversely affected the sailing qualities and was a problem with some of the Royal Navy ships (many of which came from various sources such as captured enemies).

Now I get it. I started to think you were referring to Mr. Hog and Ms. Sag and couldn't make the connection to a boat. Flatlander, living many hundreds of miles from anywhere something with USS as the start of the name would be floating.

Dave,
The survey started by setting up a baseline from front to back on both sides of the ship. Nails were set in the teak surface and the legs were marked so we could replicate the same set up while the ship was in dry dock. I don't recall how we dealt with being level while in the water, but then I don't recall what I did last weekend.

There were a series of cross sections taken from the front to back while in the water and then while in drydock. When we came back to the site while in drydock we had to find the same nails. Unfortunately the NAVY had just put a new polyurethane non skid surface on the teak deck (we had to cut through and find the nails). Once finished the data was plotted on a graph and sent to LANTDIV.

Both ships were done while I was a rear chainman and I-man. I'm sure I left out some details but the final p;lot did show how the surface changed. It was actually quite interesting project when I look back on it.

Gag and Sag surveys

These would be surveys done by my dad Gilbert A. Gardner and me Steven A. Gardner.

Gag and Sag surveys

-now that's funny...

I'm glad you clarified! My mind was somewhere else, especially with the "sag survey" part....

"Nag and sag" surveys would be....

Maybe I won't go there.