John Builds Iconic Military Model Twist Clamps
by twisting the alternative wooden side it clamps together,
The Clamps are handmade so not an exact size but the wood part is around 35mm long and the Jaw 25mm
You can place the clamp through a porthole or gun port and apply pressure both side of the hull to secure wood whilst gluing etc.
When the glue has dried by spinning the wooden moving side it releases like a nut. .