Ron P

I saw those Sage Drives on a Skater. They move in many direction.

Left right
in out
up down

You can trim them and then also raise the props.

I know that a hull must be designed with some additional rocker to work with surface drives. Don't put them on any ol boat.

I don't know why they aren't more popular. They seem to break less than Bravos and give more speed because of less drag in the water.

GLH

They are very efficient to ram into the docks or other boats in close quarters.

cuda

Easy now glh, I haven't rammed one yet........but I come in REAL slow.

vonwolske

Prop cavitation is not a problem because the prop is designed to only use the back face of the blade as it kicks the water back for thrust. A conventional prop relies on suction on the front of the blade in addition to the rear face thrust. Regular props have a max speed around 100 before the cavitation problem starts. Surface piercing props are also called super cavitating props and have no upper speed limit.
Surface drives usually implies something that looks like ASD or Kamma extending out the transom. Surface piercing drives also include anything that runs the prop half out of the water at high speeds. Whether they they look like I/O style, Sage, ASD, Kamma, or outboards raised really high on the transom they still are surface drives in the general sense. None of them are effective at raising the bow of the boat because the propeller is only biting at the top surface of the water. They can't trim the boat up because the reaction force generated on the blades is nearly in a straight line with the transom and can't generate any significant moment arm (leverage) on the transom (back part of the boat).

X-Rated30

Actually, I have always worried about pulling off from the dock in a bad current, a funny wind, or both, and running them down someone's boat like a giant can opener. Haven't had a problem yet, though.

Rik

Paul Cook had no relation, role or partnership in the Arneson Surface Drive at any point. They (Betty) wanted to purchase the distribution rights to the drive, but with no distribution network or infrastructure in place, Arneson went with an alliance with Borg-Warner at the time.

Surface Drives have been around since the time of the Oar. Every Canoe has one.

As for bow lift from a surface drive, no matter who makes the drive itself, be it a Mercury I/O to a Yamaha outboard, once they are on top of the water there is no means of gaining a positive trim position to create bow lift.

X-Rated30

Thanks for the post. Is it true that most boats that have what we consider a surface drive have some rocker to the hull or at least no hook? If so, why?

BigSilverCat

big spray with #4s

Rik

A hull with Rocker or a hull with steps or no steps?????

What's needed for a surfacing application to work well is a boat properly setup with a bottom design that runs efficient on its own, meaning they do not rely upon the stern drive to compensate for the bottom’s design problems.

With the boats designed today, stepped that is, they are designed to run more efficient on their own not relying upon the positive trim from outdrives to make the boats attitude.

This probably has come as a result from the manufacturers searching for more speed with a highly raised X dimension and thus lack of trimabilty from the drives has forced them to design an efficient bottom design.

With this lack of positive trim coming from the out drives and the boats performing well with a better bottom design, they have actually designed a bottom that works very well with an Arneson Surface Drive.

Hot Duck

Here are the Weismann drives on the Lucas Oil Super V and a link to the Weismann web site.

Weismann Drives