Indoor SUP Trainer?

Hey all — I am doing a unique triathlon early next summer where the first leg is a run up a steep sand dune, the second leg is the bike, and the third leg is a row.

It is called the M22 Challenge for those interested in checking it out:

For the row, you can either use a kayak or a Stand Up Paddleboard (SUP) - I am going to use the SUP, since I do this recreationally in the summer anyway.

However, the race is in early June, and I live in Chicago - which means I won’t have a ton of time to train on the SUP (due to weather) before the race…so I am looking into indoor SUP training options.

I also think this could have a great crossover benefit to cycling in that it really is amazing core work.

However, as far as equipment there aren’t many options out there. The only one I could find is from VASA (link below) and it is really pricey.

I’m taking a chance that this group might know of other equipment options out there for SUP rowing specifically? Or know any workout protocols that simulate the SUP action?

Thanks in advance for any input.