The bolt on shaft system from Seatorque control systems.

Results of recent trials.

5% reduction in fuel burn and engine loads as well as increased rpm and boat speed. Reduced noise an vibration. This was a back to back test on a vessel first run with conventional shafts and then fitted with Seatorque BOSS system. Video shows a change in wake pattern confirming that the underwater dynamics have altered considerably, we should have the video soon and also detailed charts of direct noise and vibration figures over the rev range.

answering many of the problems associated with assembling and aligning a traditional open shaft system as well as offering a number of other benefits.

Manufacturers website with shaft size calculator Seatorque control systems

External and internal view, click on image for more detail.

have a look at a schematic for a complete installation Schematic link

When comparing a traditional rubber bearing supported shaft system where thrust is taken on the engine mounts to a Seatorque system...

As a manufacturer you will see

Reduced installation times of complete shaft systems.The BOSS™ system has been installed in less than 4 hours by some builders on their first installation.
Reduced number of parts ordered.
Can be easily fitted to existing hull designs with minor modifications.
Eliminate the need for alignment checks after sea trials.
Eliminate vibration and noise from shaft system.

This can be achieved as the complete shaft system from Prop to coupling is one unit containing all support and thrust bearings. We can also be supply P brackets to suit this type of shaft. Alignment issues are simply eliminated with the use of a double universal sliding coupling, thrust loads are taken through the hull fitting, allowing the engine to move independently of the shaft on softer mounts.

Up to 8% in extra delivered horse power can be achieved over a conventional shaft set up, or the difference between Volvo D11-670 and a D12-715 engine installation. The system has mechanical losses of 2% and eliminates the need for cutless bearings, stern glands, stuffing boxes or dripless seals and the associated plumbing. A simpler, cleaner and dryer installation.

As a customer or boat owner you will see

Extra horse power at the prop up to 8%
Greatly reduced noise and vibration
Reduced maintenance
Lower running costs

Rotating shafts in the water produce drag, they also create turbulence as the water travels towards the prop.
The shaft has much greater support along its length, holding the shaft inline allows more power to be transferred to the prop.
Running the shaft in oil instead of unfiltered water, sand and silt prevents bearing and shaft wear.
Fewer lift outs or dry docks for cutless bearing replacement or shaft maintenance.
Longer life of engine mounting components.