Some commercially available products may be helpful for adapted rowing. A few sample products are shown below. Note we are not intending to endorse any particular companies here, just showing some examples of products that exist.
Harnesses and Binders
Neoprene abdominal support with Velcro 
Bodypoint H-Style Shoulder Harness and chest strap 
Neoprene abdominal support with Velcro 
Simple waist strap 
Weight lifting belt 
Bodypoint Universal Elastic and Velcro Strap 
Trunk/Torso support 
Gloves
SciFit adaptive hand grips – neoprene 
Harness gloves 
Active hands – adaptive gloves 
Classic gripping glove 
Gloves with wrist support
Handles and Grips
Two hand rowing attachment – narrow grip 
Two handed rowing attachment – wide grip 
Two hand rowing attachment – handles 
Single hand rowing attachment – wrist attachment 
bar grips (thick) 
Single hand rowing attachment – wrist attachment