propeller shaft bertram

prop bertram



here the picture of the prop the strut and the shafts
kind regards
pascal

 

dear Baeckmo

i have been sending a picture of prop and shaft a little there after
kind regards
pascal

 

That doesn't look like the bottom of any 42 Bertram I have ever seen?

There is too much shaft between the strut and the prop so that wont help the vibration problem at all.
Havign a bolt hanging out of the side of the strut to secure the bearing is not great, maybe a grub screw would be better or none at all depending on the type of bearing that is in there.

Do you have a photo of the hull?

 

bertram or not bertram

Here the boat
kind regards
pascal

 

yep that is one
They didnt make the Motor yacht version in OZ so I have no experience with them.
It was the keel that I have not seen before?

 

Performance is also a factor of how much energy goes into shaft bend/whip rather than thrust.

You could try a rigid bearing (I assume you are still using rubber bearings) we have had performance increase reported from users of rigid phenolic composite bearings rather than rubber. Some makes also resist marine growth on the shaft and bearing surface.

 

bearing

hello

could you said me a little more about those bearing rigid
kind regards

pascal

 

When you apply thrust to a shaft it will want to bend, it is the bearings that hold it in place or llimit this movement. The closer you can hold the shaft to a straight line position the less energy will be used up in the shaft bending from its centre line as well as corkscrewing as torque is applied.

If you use a rigid bearing the shaft canm only move as far as the clearance between shaft and bearing surface. Even when running on a water film the shaft can increase pressure in this film as it starts to bend, this increase in water film pressure will force rubber to give allowing the water film to remaain but the shaft to move.

Use a rigid bearing material and the ammount of shaft bend is far less.

There are a number of composite bearing manufacturers I work with one make from Perth which I believe performs better than most if not all of the others. Do a search for marine composite bearings and have a read. They are used in quite a wide range of vessels.

 

Rigid Bearing

HELLO

i WILL SEE IF I CAN FIND SOME OF THOSE HERE IN THAILAND
ALL THE BEST

KIND REGARDS

PASCAL

 

dear typhoon

for the hp i am very sure of the 335 hp because i get it out a detroit allison paper with all the details brake hp shaft hp ....
if you give me your e mail i will downloard the form and send it to you with everything official i got pictures ...
i go actualy 16 knots with very bad thailand made junk propellers of 23 inches

thanks for your help if you interested going further send me your e mail
kind regards

pascal coldefy