Engine to suit PP jet

To every motion there is an equall and opposite motion.

Thats simply how a jet works, in some parts of the world they call them a pump,--probably because thats what it is.

Most but not all jets fire out the wieght of water at the surface, this is not necessary but helps to fascilitate steering and reverse plates.

A quick glance under the boat would at first seem to be clear of obstruction and parastic drag. Not so,--Its all in the jet, the intake gate, bends in the unit, impeler hub, shaft, wet surface area --its all there. Just not as obvious as a conventional drive

 

Apples to peaches

To Quicksilver,
you are young - so I will be kind.

(1.) I very carefully said, ".....an ordinary prop can do."
Surface Drives are not " ordinary ". Or common. They cost a lot and
have NO bottom end.
Check out how many fishermen have S. Drives.
And how much a Swiss made " Chopper " retails for.

It's well known that if 100 mph is the ONLY objective - they will get the
job done. However, they, like all drives, they have their limitations.....

(2.) I designed a boat that the client, against my objections, installed
one of the least efficient jets available. The O/B you refer too.

I know it well. It's geometry is very different than what messers;
Hamilton and Parker (The man who invented the PP.) knew well.
They did their best way keep the flow in line with the direction the
boat is going, in their designs.
Whereas; the O/B is band - aid engineering. If the flow was any more circular,
it would barely function at all.

(3.) Rather than me, going to a site, to learn what I'm already know.
- It will be much more productive for YOU to go to the:
Rolls Royce (Marine)site. Where you will see them: directly, contradict
what the O/B site says.

Which one of these large corporations is lying, out right ?
Neither ! Because these jets are only, very distant cousins. - Twice removed.

Even closer at hand - there are several pages
- right here on Boat Design Forums, devoted to Jets......

Click on Search for: " Jets, jet pumps....."
A very good post - by brian eiland - that is essential that you read.

- Particularly; the third quote down.

Don't bother to apologize - get some rest....

 

I'm not going to continue this bs argument on your thread James. I apologize for that, I hope your boats turns out the way you want.

To tri-star- you've got mail *****, stop jacking this thread!