Rodman 41 IPS drives

[Its_Only_Money]

Re: IPS Theory chapter 2

"The vertical vector does not act at the gearbox, it acts at the propellor."

Now why's that then /forums/images/graemlins/confused.gif the only force at the prop is the thrust created by the prop forward through the P bracket and directly up the shaft, assuming the shaft is free to float in the P bracket then the force is transmitted to the thrust bearing wotsit in the gearbox isn't it??? If what you say is true then if the prop wasn't mounted in a P bracket it would be forced up - and I can't see why - it doesn't happen with the long-propshaft-in-the-water Thai boats does it? (where the shaft is free to pivot in all directions).

Now the bit where we agree outright I think....

To use your example of the outboard, if you trim the leg in (to a shaftdrive sort of angle???) fromm a parallel running angle it will lift the stern, the effect is to bring the bow down but it is the stern that is actually lifted. Converesly if you move from shafts to IPS it must, all things being equal, lose lift from the stern mustn't it???

In moving the thrust angle you must be changing the moment that the thrust force has around the CoG also???

 

[jfm]

Re: IPS Theory chapter 2

Sorry was long pub visit.

There are sideways prop forces too, hence need for P brackets. Thais just have strong arms

I guess the only point I'm making is that the attachment point/point where thrust is applied to hull, eg gearbox mount bolts, doesnt matter,

Yes agreed, on my outboard example trimming right in will lift the stern and drop the bow. That happens whether outboard is bolted to stern or bow (I mean the bow using my soecial bracket arm). Moving from shaft to ips all other things being equal will alter the prop angle so lose the stern lift as you say, all agreed

Gotta run to look at a boat, will reply to Deleted User later