Reddit reviews SportRack ABR528 Standard Block Island 6-Inch Canoe Kit
We found 1 Reddit comments about SportRack ABR528 Standard Block Island 6-Inch Canoe Kit. Here are the top ones, ranked by their Reddit score.
Four durable 6"-long closed cell foam blocks to protect canoe and vehicleNon-skid underside to prevent movement on the vehicleIncludes two 15"-long strong polypropylene center straps with chromate bucklesIncludes two extra-long ropes for front and rear tie-downsFits Thule, SportRack, round, factory racks and bare roofs
You can probably mount some Thule Hullaports on them, though that's rather pricey.
A cheaper route would be some foam blocks.
Either way, you should invest in some bungees or tie-downs.