American engineer (1866–1945) who developed the first submarine to operate successfully on the open seas. Original signed pencil sketch of a cross-sectioned salvage tube on a beige 8.25 x 10 lightly lined sheet, with Lake adding copious notes and signing at the conclusion, “Simon Lake, Jan. 15, 1940.” In part: “Method of making up joint to salvage tube—the tubes are made up with male & female joint—section about 30 ft or more in length—the male end is entered the female section & the water pumped out between the bulkhead.” In fine condition, with a tear in the upper blank area. Pre-certified PSA/DNA.
This item is Pre-Certified by PSA/DNA
Buy a third-party letter of authenticity for
$35.00
*This item has been pre-certified by a trusted third-party authentication service, and by placing a bid on this item, you agree to accept the opinion of this authentication service. If you wish to have an opinion rendered by a different authenticator of your choosing, you must do so prior to your placing of any bid. RR Auction is not responsible for differing opinions submitted 30 days after the date of the sale.
We use cookies on this site to improve your experience. By using this site, you accept our use of cookies. To learn more, please see our Privacy Policy.
