I want to hit the water up but all my searches have come up with exactly diddly.
anyone know where you can rent a boat or if this is even viable?
Also, anyone else want to come?!
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If you were looking for something smaller, there are canoe and kayak rentals all over the place, but one of the most popular places is at the University of Washington stadium.
edit: are you going to have a car? If you're relying on public transport, the kind of places you can get to might be limited (e.g., downtown Kirkland probably not as great of an option).
University of Washington Waterfront Activities Center - Located behind Husky stadium on Montlake, this is also available to the general public and your cheapest option.
http://depts.washington.edu/ima/IMA_wac.php
Agua Verde Cafe & Paddle Club - Montlake, rents kayaks and has Mexican noms!
http://www.aguaverde.com/
Green Lake Boat Rental - One of Seattle's finest summer parks! Kayaks, Canoes, Bicycle Boats, Sail Boats and Stand Up Paddle Boards.
http://www.greenlakeboatrentals.net/
Lake Union:
has several hourly (or more) trip type things down there, one of the major players there is Argosy:
http://www.argosycruises.com/
they also do trips in the sound and a dinner cruise I hear is pretty fun.
Also on lake union is the electric boat company.. small crafts.. and limited travel area.. but does get one on the water: http://www.theelectricboatco.com/
Advantage of some of the lake union options is one can hop on the Seattle's Train that goes out there from near westlake center.
Puget sound:
Argosy again.. see link above.. and not sure who else..
but one can hope on the ferries too as a way to get out on the water.. (and probably the cheapest option)