T2x

Here's an earlier record holder...to give you an idea of how a really maxed boat should look. When horsepower is not a function of checkbook size..... you need a LOT more engineering and driving skill to go fast.

T2x

gdfatha

==

Here is a photo of the record setting hull that hangs in the Race Roce Cage in Orlando..

OldSchool

That's an amazing picture. It looks like negative trim!!

Shane

Rich,

Is that the motor that Dick built down at "The Alley"? How fast was his driver going when he broke the record, then took the second pass and never came back?

KiloKat

There is a formula I use to compute air entrapment psi vs tunnell compression ratio which in turn gives me an idea when any weight of cat will want to fly. You have to begin using negative trim on stern drive (transom mount) boats before this speed. Shaft drive boats are entirely different because their thrust is at the keel which in turn tends to push the nose of the boat over more, ie - shaft drive boats are safer at highest speeds.

T2x

Actually, that isn't necessarily a "shaft drive" phenomenon....... Many shaft drive boats have been created that run the prop angle parallel to the bottom. Rather, the safety feature comes from forward suspension as found on hydroplanes, or true four point designs...as opposed to tunnel hulls or cats. Basically a hydro is a faster design than a cat because the drive is set up (trimmed under) in such a way as to lift the stern out of the water completely at speed and "prop ride" as seen in the picture above of John Sherlock in Dick O'dea's hydro.... who by the way was "only" going about 140 in the picture. However, you must remember scale speed and its impact. The O'dea hydro was about 18 feet in length....which , all things being equal (and they never are), equates to a 36 footer at 280 mph...and a 46 footer at 360 mph.

I maintain the fastest design concept extant...is the 4 point ram WING.......pictured below.


T2x

T2x

The ONLY way to run a hydro or 4 point is to "fly the hull"..with the engine(s) "tucked under".........

T2x

KiloKat

Absolutely correct but my comments had to do with the reason for negative trim used in the pictures above and not which style hull is the fastest. However, I tend to agree with your comment about the 4 point ram wing. Who knows, maybe we'll see an entirely new concept design incorporated into an offshore catamaran hull in the future that will utilize the best of both worlds ...

T2x

David:

That's something we can certainly agree on........

If only the damn things ran in rough water

T2x

timucin

dunno past but will be me in near future