Guy Taylor received U.S. Patent 8,257,121 for a “Boat Propeller Shield” on September 4, 2012. His 3PO Propeller Shield automatically swings up from his hexagonal shaped Navigator guard when underway to reduce drag. The shield automatically falls down to protect people behind the boat when the boat is at rest or backing up.

We started encouraging developments in this area (flip up guards) with our October 13, 2006 post titled, The Flapper. The Patent Office cited out previous work and some of the references we cited as references for this patent.

A copy of the front page of his most recent patent, U.S. Patent 8,257,121 is below.

You may remember, Guy Taylor received some previous patents for his octagonal 3PO Navigator prop guard. Among them are:

• U.S. Patent 6,159,062 for a High Performance Propeller Guard
• New Zealand Patent NZ24046 for Guard Ring for Outboard Motor
• U.S. Patent 5,098,321 High Performance Boat Prop Guard with High Strength Attachment

While the 3PO Navigator propeller guard is not a “new” guard we went ahead and put this post in our new products section because it’s shield is still relatively new and Guy Taylor was recently awarded a U.S. patent for the shield.

The Navigator guard patent includes data comparing “with shield” to “without shield” performance for 0 to 20 mph average elapsed time, 0 to 25 mph average elapsed time, time to plane, planing speed, and average top speed. The flip up “shield” is shown to have little impact on performance. For example the “shield” reduces top speed by about 1/10 of a mile per hour.

Among the more innovative elements of Guy Taylor’s 3PO Navigator propeller guard are the use of bent arms a part of the hinging mechanism. When the shield is in the down position, the arms extend upward from the top of the shield, then bend forward to the hydraulic trim cylinder pivot point. The use of bent arms allows the shield to pivot up and ride much higher along the surface of the water than it would if it just pivoted at the top of the shield. Attaching the arms to the trim cylinder pivot makes for a nice clean design.

The patent also describes the use of a planing surface on the shield that extends from the shield toward the propeller. This surface allows the shield itself to plane on the surface of the water vs. just being drug through the froth near the surface.

The guard also includes as cutout in the shield to allow the shield to pivot up without hitting the anti-ventilation plate (flat surface on the drive above the propeller that reduces the amount of air that can be sucked down from the surface.)

Guy also notes boats are quicker out of the hole with his propeller guard and have less bow rise which significantly improves visibility from the helm.

The 3PO Navigator along with its accompanying shield was used as the exemplar propeller guard (example) in the Brochtrup propeller case. The jury found in Brochtrup’s favor for $3.8 million.

We wish Guy Taylor great success with his 3PO Navigator propeller guard and thank him for the many years he spent in developing it and in developing its accompanying shield. We are especially excited to see a “flip up” guard enter the U.S. market. We hope the Navigator’s success in the marketplace will encourage the development of other propeller safety inventions.