Shafts thru the transom?

[gonzo]

If the rudder gets enough water, there is no way the propeller runs ventilated. I asked about some data before, because cavitating propellers become efficient at over 40 Knots. If your boat is running 30 Knots, it is slower than one with an outdrive. I still don't really understand the advantages you claim. Can you post a photo of the stern of the boat planing? Seeing is believing

[tom kane]

I have been watching Simplicity-Marine for some time..just had
another look.Seem to have some knowlegable contacts.Mostly
conventional and now widly used components.Still have a long way to go.I do not know how shallow draught is achieved when a craft draws so much water.Where does surface propulsion
start and finish?. tom kane

[Palmer]

It looks like the bottom third or so of the rudder would be immersed at speed. It would only be all the way out of the water when the wheel is too. It doesn't look like a bad setup, my only question would be regarding the efficiency of that type of wheel when it's ventilating

[8knots]

How about water jets such as berkly's? few moving parts and fairly easy install and the ultimate in shallow draft. Just an idea
8Knots

[tom kane]

Observant Palmer..Jet propulsion just like other systems are
badly misunderstood in their capabilities,especially shallow
water operation.Some do produce an enlightening Operation
manual.tom kane.

[gonzo]

If jet drives were "badly misunderstood", and I wished they were, we wouldn't have an invasion of PWC's.

[Willallison]

nor would 90 % of commercial fast ferries and mega-yachts be using them.....

[tom kane]

Thanks will..for proving a point..mega-yachts and fast commercial
ferries..always operate in shallow water.I wonder what happened to our surface drive forum..againstum.Tom Kane.

[Willallison]

Sorry Tom - don't quite understand your point. I was agreeing with Gonzo - jets are a well established, veru reliable and afficient drive system.
As with all systems though, they appropriate and inappriate applications.

[BrettM]

I didn't realise that the large cats used to crosss Bass straight and the english channel at high speed used jets because the water is shallow...

[tom kane]

You are right will about in appropriate usage.manafacturers
usually supply sensible saftey and operation information.
Knowing the un-biased history and the people who developed
and made the important break-throughs,and the financing,the litigation and the patent claims of several leading jet systems
is interesting.Has some one said jet systems are not what you
say they are?What has happened to surface drive forum.tom kane

[Willallison]

I didn't realise that the large cats used to crosss Bass straight and the english channel at high speed used jets because the water is shallow...

Tom - sorry we didn't mean to steer the subject away from surface drives, but for the sppeds mentioned by CaptnPPan for his boat (30 odd knots) then they would be an efficient propulsion choice.

[gonzo]

Speed is at the core of this discussion. At less than 40 knots, surface drives make no sense.

[dougfrolich]

Whoop there it is!

I have a boat in my gallery with a similar drive to the capt. Just makes good sense for 40+

[dougfrolich]

The real deal