does anybody have pulse drives?

[Freebee]

I have been given a demonstration of the pulse drive(surface piercing props) system today and Im dead impressed. Does anybody have any experience of this system?

www.pulsedrive .com

NB I have no connection to this company.

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[omega2]

Mike Bellamy at Lancing Marine makes one

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[PaulF]

They appear to work quite well at very high speeds. All Class 1 offshore racers use them. I know of one 45ft 'cruiser' type boat that has them on. Took a lot of work to get selection of prop correct, but goes well, gives an amazing rooster tail, but low speed handling somewhat hairy.

First surface piercing props used 1930's I think. Use extensively on model hydroplanes in the 50's and 60's. I have had no contact with boat models since, but sure somebody else will lob in an offering.

Mike Bellamy was mentioned. I think he had a surface drive on a boat with an E Type Jag engine in it for some years. Perhaps he developed the drive on that boat?

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[Freebee]

The Demo I had was in a Hunton gazelle 35 and the rooster tail at 46 knots was well er, impressive, as for low speed handling she could spin in her own length at slow speed. Im on the river at Christchurch and what impresses me is the fact that you can run the props at low speed very near the surface thus avoiding all the sand bars.
My enquiry was to try and find out what they are like long term, how much maintenance etc.

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[kimhollamby]

Clarification

Having had a quick look through posts on this thread worth pointing out that Pulse Drive is just one example of what would generically be described as a surface drive. Mike Bellamy has, for many years, promoted the British-designed LM Drive. US company Twin Disc, who offer the Arneson and Mondodrive surface drives recent acquired Swiss surface piercing prop specialist Rolla. ZF is offering the Buzzi-designed Trimax drive as the G-Drive. There are others out there too.

Most systems vary in the detail of steering and trim; some are articulated (Arneson was a pioneer of this), some are fixed.

Buzzi-designed surface drives recently made it onto the Sealine C39 as an option but I believe that derivative has not been sold at all -- certainly in original tests made by a bunch of press it couldn't better the efficiency of sterndrives. Modifications on props later closed the gap in performance but left a big price differential.

Received wisdom on surface piercing arrangements is that they only start to hit efficiency at speeds of 25 knots plus. They have tradtitionally been very sensitive to prop choice and the props themselves are expensive, so swapping them out for replacements not a cheap option. You also need to work the trim on trimmable drives to get the best out of them and there can be some question marks over practicality when sea conditions get up when loading varies dramatically as initial bite for acceleration can be quite a bit more long-winded.

Surface drives used to be very awkward around the marina but the ZF / Buzzi drives on the Sealine were impressive and it sounds from your post as though the Pulse Drive is similarly nimble. Haven't experienced the Pulse Drive out on the water but it has been garnering a lot of publicity to-date.

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