v drives..... whats your experiences...

[Robg71]

good points... bad points.... anything please

 

[kashurst]

I have v drives on D9s - touch wood all OK so far, 1150 hours. Access to glands very good. Only problem on my boat is access to top of the engine to do tappets etc as no deck hatch directly above them. Not that much different to normal gearboxes, one extra gear I think and the shaft comes out the front rather than the back.

 

[RobWales]

Surely Rob V drives will negate the tunnels are per the original cad drawings?

 

[Robg71]

looking in to possibility of creating more space..
this vid has given me ideas, and should not affect access too much as there is a good size drive shaft.


https://www.facebook.com/photo.php?v=386375574798453&set=vb.138104592958887&type=2&theater

 

[Robg71]

Surely Rob V drives will negate the tunnels are per the original cad drawings?

not at all. the v drives will still exit the prop tunnels as per original spec. the tunnels are to give more thrust, and allow a straighter/shallower shaft angle.. we have enough space to come back more with the motors, gives me more cabin room.

(i am purely thinking out aloud here folks

 

[Keith-i]

Does the specific location of the engines have any effect on centre of gravity in a boat that size?

 

[Robg71]

Does the specific location of the engines have any effect on centre of gravity in a boat that size?

yes...
we have moved them back when we went to full planing hull.
we didn't want a stacked engine and gearbox, but this type of prop shaft arrangement gives the opportunity to split them, and create more cabin space.
would have to go back to designer, for calcs. luckily, though, for now, he has not cut steel. hes still sat on it, while finishing another drawing. but, i need to move fast.
the yard are getting agitated by delays. the engine beds etc would be a simple move.
prop shaft alignment wont be affected.

 

[jfm]

Assuming all the consequential effects are ok (different CoG, access to stern glands, etc etc) there is nothing fundamentally wrong with a V drive gearbox. There are zillions of units installed and there is no reason to think they are worse/less reliable etc than "normal" gear boxes

Obviously the propeller thrust load will be taken onto the gearbox mounts, not the engine mounts, but designers can deal with that and it's a well trodden path

 

[Robg71]

Thanks JFM
we have a thrust bearing direct in to the hull to take drive forces,
I have emailed yard, and designer already.
personally i really would like this change, as it gives a lot more room up front to play with. The engine room is not well utilised. (heres me saying that now, that will come back and bite me....

 

[jfm]

Plenty of posters on here have or have had them, with no problems afaik. Kashurst as per above, and also MYAG in his Y80, Deleted User in a ferretti, TCM in his Leopard 23, SpottyDog6 as of the other day, some of the Fairey and Levi owners, and maybe stacks of others that I'm forgetting.

In the facebook video that you linked to, the jackshaft was very long and the engine was very far aft in the boat. I have no idea why or what boat it was, but it would be unusual to put the engines that far back. It did give him excellent sterngland access of course

 

[Robg71]

Im not expecting anything as drastic as that vid..... may be a bit arse heavy... may even get away with just a bolt on v drive, need clarification as to access to stern gland.
I await the reply with interest. I broached the subject a while ago, now im putting my foot down for an answer...