Tabs of plan hull

What is the Tabs and what is the Trim Tabs angle?

also what is the Spray Rails?

(for plan hull)

 

Trim tabs can either be adjustable by being mounted on a hinge on the outside of the transom or they can be fixed by putting a wedge on the bottom of the boat at the very stern. Some hinged tabs have power adjustment and others have a mechanical adjustment whose angle is only changed when the boat is not underway.
Spray rails are longitudinal strakes whose lower surfaces are horizontal in section view, or nearly so. They tend to knock the spray down and some people call them spray knockers.
If you look around on the photo gallery you will find examples of both tabs and spray rails.

 

Have a look on...

www.boatus.com/boattech/trimtabs.htm

 

thanks for help