You can get replacements for most models from Merritt Marine in Hillsborough, NC. Check out
http://www.merrittmarine.com for contact information.
BTW if you are a Triumph owner you're invited to register a free 1-year Captains Club Member subscription with us by clicking on the Register link above and entering the required information. All the information must be provided in order for your account to be activated. The contact information will only be seen by me (Administrator of the website) and Triumph Boats personnel for the purpose of verifying boat ownership and for communicating with our members.