Roof racks and roof rails have cargo load weight limits set by their manufacturers.
Example - Your roof rails may ony be able to carry 80kgs and your roof racks 75kgs. This means you can only carry 70kgs of cargo on your vehicle (your racks already weigh about 5kgs). The vehicle manual and the roof rack manufacturers provide this specific information.
The Loadezee system base frame weighs 15kgs and the sliding frame 15kgs. The RHS cradle as shown in the images can carry max. 20kg surfski or craft.
The LHS cradles, if fitted, can carry another 10kgs bringing the total weight to 30kgs.
Alternatively you can carry 2x 15kg surfskis instead, thereby staying under 30kgs.
For reference, the surfski in the images weighs 13kg and is 6m long.
To avoid damage to yourself and your Loadezee it is important to lower the system to the side of the vehicle gently when unloading. If 30kgs of load prevents you from doing this then the load limit should be reduced to a weight you can still lower with control.