Tailshafts
Tailshafts
Using only the finest quality virgin steel, BT Marine shaft assemblies are supplied in diameters from 25mm to 300mm. One piece shafts are available in lengths up to 14 meters.
Shafts can be supplied in a variety of styles from plain tapered and precision ground to stepped or sleeved dependant on upon the method of lubrication and application. All of our shaft assemblies are supplied complete with keys, coupling nuts and propeller cone nuts and can be ordered with compliance to any IACS society.
We can offer the following materials:
Mild Steel 070M20 (1.0402):
Traditional mild steel for use in sealed grease or oil lubrication systems. Shaft life can be extended by fitment of bronze or stainless steel sleeves by way of bearing areas. In applications where the shaft will be subject to saltwater exposure, it can be wrapped in an GRP epoxy cladding for protection.
Stainless Steel: S304 (1.4301):
Marine shaft material for water, grease, or oil lubrication offering fair resistance to corrosion and moderate wear properties.
Stainless Steel: S431 (1.4057):
A high strength stainless steel for use in situations where the shaft torque and power dictate that the use of mild steel is not possible, offers moderate resistance to corrosion.
Stainless Steel: S316 (1.4401/1.4436):
Traditional marine shaft material for water, grease, or oil lubrication offering good resistance to corrosion and good wear properties.
A martensitic, chromium-nickel-copper precipitation hardening stainless steel used for applications requiring high strength and a moderate level of corrosion resistance.
Duplex F.51 (1.4462):
A modern high strength stainless steel alloy offering excellent resistance to corrosion with outstanding wear properties, particularly useful for high speed, and high power applications where smaller shaft diameters are desirable to reduce drag from underwater hardware.
Super Duplex F.55 (1.4501):
Another modern Super-high strength stainless steel alloy offering excellent resistance to corrosion with outstanding wear properties, particularly useful for high speed, and high power applications.
Below is a table of typical mechanical properties for the materials:
| Material | 070M20 | SS304 | SS431 | SS316 | 17/4ph | F.51 | F.55 |
|---|---|---|---|---|---|---|---|
| Tensile Strength (N/mm2) | 430 | 505 | >800 | 550 | >930 | 700 | >805 |
| 0.2% Yield Stress (N/mm2) | 215 | 215 | >600 | 240 | >724 | >450 | >530 |
| % Elongation | 15 | 70 | 14 | 60 | 16 | 40 | 25 |
Our Services
Propulsion Packages
The flagship service of BT Marine is the design, manufacture and supply of a complete propulsion system for your vessel.
Design & Engineering
At BT Marine we believe that each individual customer should be just that ? this is why we take each project on a case to case basis and design each component specifically for the needs of the customer and vessel.
ROV Thruster Propellers
BT Marine are one of the world?s largest manufacturer and supplier of Aluminium ROV Thruster Propellers. We can cater for bespoke design, low volume orders through to high volume production with high quality delivered at competitive prices.
Hybrid & E-Propulsion
BT Marine have developed a range of propeller designs and blade sections that are geared exclusively towards Hybrid and E-Propulsion.
