THE VAC-U-BOAT GUARANTEE: 

As shown in the instructions: "If you open and inspect this kit and for any reason you do not wish to keep it, return all of the parts to their bags and repack the kit into it’s box along with a copy of the receipt. (Keep an original for your records.) Mail to me via the United States Post Office, Parcel Post with Delivery Confirmation.  . . .  Upon receipt of the complete kit, I will reimburse you the original cost plus the cost of the return postage shown on the package and mail those funds to the name and address on the receipt copy. I will replace any defective part found during the assembly or operation of the boat for a period of three months after the purchase date..."

If you hopelessly mangle an important part during the assembly, we can talk.

TM