Just checked the Transport Canada website. The card is a bit of a joke what with on-line testing by 3rd party companies but it looks like you need one to rent.
There are a couple of folks that run tours out of Portland. Here is one of them:
Rideau Lake Boat Tours Tel: (613) 272 - 2895
Portland Village, Portland, ON
I have my own boat so have never used their services.
https://www.tc.gc.ca/eng/marinesafety/debs-obs-quick-quick_visitor-1610.htm
The Competency of Operators of Pleasure Craft Regulations require that all operators of pleasure craft fitted with a motor have proof of competency and proof of age on board at all times.
The Regulations are being phased in as follows:
• All operators born after April 1, 1983 are required to have proof of competency since 1999.
• As of September 15, 2002, all operators of craft of less than 4 m (13'1") in length, including personal watercraft, will be required to have proof of competency.
• As of September 15, 2009, all operators will be required to have proof of competency.
How the Regulations Apply to Non-Residents
The Regulations apply to non-residents:
• If they operate their pleasure craft in Canadian waters for more than 45 consecutive days or,
• If they operate a pleasure craft that is licensed or registered in Canada (including rented or chartered boats).
• The Regulations do not apply to non-residents who operate their pleasure craft in Canadian waters for less than 45 consecutive days. Please note that a proof of residence will be required on board at all times.