John Miele

When designing a propulsion system, the size of the shaft becomes an important consideration. Yes, there are formulas that are used: Shaft diameter formula D=(321000*SHP*SF/St *RPM)^ .33 Where D = shaft diameter ,inches SHP = Shaft horsepower SF =Safety factor ( 3 for yachts , 8 for heavy commercial use) St =Yield strength in torsional shear ,in PSI RPM = Revolutions per minute of propeller shaft Shaft bearing spacing formula L = ( 3.21 * D/ RPM)^0.5 * ( E/ Dens)^0.25 Where L = Distance between bearings ,in feetD = Shaft diameter ,in inches RPM = Propeller revolution per minuteE = modulus of elasticity of shaft ,in PSI Dens= Density of material in pounds per cubic inche. SHAFT MATERIAL CHARACTERISTICS Shaft material                                  Yield strength                              modulus                       densitiy lb/ci.in Stainless steel 30... (more)

Interesting story about the US Navy patrol fleet

An interesting article about the role of patrol craft in the US Navy. At France Helices, we are believers in the fact that different missions require different propulsion systems. From Wired: Small ships have never really been the Navy’s thing. Tasked with deploying all over the world, far from its U.S. shipyards, the Navy prefers big vessels capable of carrying lots of fuel and supplies and taking a beating on long ocean crossings. The average size of an American destroyer has more than doubled since the early 1990s, now tipping the scales at 9,000 tons displacement. But sm... (more)

Dealer Profile: SCAN Marine

SCAN Marine represents France Helices in the Philippines. With locations around the country, SCAN Marine can provide France Helices’ customers the level of service they have come to expect and demand. Visit the SCAN Marine web site for more information about this outstanding company and the services and products they provide: http://www.scanmarine.com.ph. Scan Marine Inc. (SMI) is a well-established corporation existing under and by virtue of the laws of the Republic of the Philippines, with business and postal address at 160 Honorio Lopez Boulevard, Balut, Tondo, and Manila, P... (more)

Does France Helices Guarantee Vessel Speed?

Yes, under certain conditions. On every order of our SDS, France Helices uses our exclusive design software to accurately predict vessel performance. There are numerous criteria that the software uses in order to project vessel speed. We can, within a 1% degree of accuracy, predict how fast a vessel will travel, using our SDS, as long as the vessel is constructed to specifications. France Helices guarantees propeller thrust 100%, and we can prove the thrust and propeller performance. However, sometimes, vessels will be built to varying degrees from their initial design. These fa... (more)

Surface Piercing Propellers

Surface piercing propellers are an integral part of the design of a surface drive. Many boat owners, naval architects, and shipyards have tried to design their own drives… And usually they end up in failure, mostly because of lack of expertise in propeller design. France Helices began as a propeller manufacturer. Propeller technology and expertise are crucial in achieving high performance from any vessel. The following article by Paul Kamen, NA is somewhat old, but still relevant. An excerpt: What is a surface-piercing propeller, anyway? Simply stated, a surface-piercing propel... (more)