"According to Doug Stephenson who worked for Whitby, through bolting became standard during the production period during which the boats were manufactured. On those earlier boats that were not specifically through bolted on the full perimeter, through bolts on 4" intervals occur on every Whitby along the port and starboard head sail tracks. Many boats have tracks extending almost to the transom.
Inspection of numerous Whitby 42s has demonstrated that through bolting was very commonly employed and any prospective Whitby owner should verify this to his or her satisfaction. Examine the joint from the interior. You'll find through bolts!"
And from a boat (Hull #70) when the cap rail was removed;
"Through bolts for the hull to deck joint were found the entire length of the boat, both sides, approximately every 12 to 16 inches apart, except where the genoa track was, and there the bolts were every 6 inches."
Anyone interested in a Whitby should visit;
Welcome to the Whitby Brewer Sailboats Site