Surface Drive Discussion

[Burns]

I am researching propulsors for a large, high speed craft and am condsidering surface drives. What are the pros and cons for this type of drive system. Is there a good solution to achieve high speed while maintaining low speed maneuverability? Why does the Arneson Drive cost twice as much as Pulse Drive? Can anybody discuss their experience with either of these products--good or bad?

[woodboat]

Arneson drives articulate while pulse drives use a conventional rudder. the Arneson should give greater low speed maneuverability VS the pulse drive but it's great complexity would explain the higher cost. As far as personal experience with either, sorry but I have none.

[gonzo]

Surface drives become efficient at about 40 knots. The fix type drives are lighter and cheaper. They also have less things to maintain or break. CAL-500 , made by Sonny Miller are of this type.

[nemo]

Hi, I attended a course at University about surface drives...
The "pro", that's also the concept behind this propulsion sistem, is the elimination of the drag due to immersed propeller axis and struts (it can be significant at very high speed), and I'd say also a better thrust position, related to a high speed craft's trim.
IMHO, these drives should be used on racing boats or patrol boats only...
the propeller itself hasn't got a better efficiency than a traditional one, and it suffers a lot of fatigue load, due to the continuos load/unload of the blades through water and air. A surface driven boat's owner should take in account that sooner or later he will have to change the propeller because it will brake.
This is one of the "cons", the other is the low speed maneuverability... Arneson costs more, because it has a ball bearing that allows it to be used as a rudder too... anyway, the turning force is granted by a very small fin attached near the propeller on each shaft. That's absolutely insufficient at very low speeds. Another problem of the Arneson, is the large amount of spray that's generated by the props... you won't have it with pulse drive, because the props are covered by a superstructure.
The conventional rudders used by the Pulse drive are big, and should be fully immersed at low speed, since the transom is not dry but immersed when not planing.

[yipster]

all i know about surface drives is hearsay, folders, shows, the .net. i do know arneson's can be hooked upto bravo II sterndrives openings.
i didnt know about the "fatigue load, due to the continuos load/unload of the blades through water and air" and it came to my mind that you may need two surface drives? one -i imagine- would have a terrible wheel effect? (walking away sidewards at the stern)

[boogie]

there is some good info here on the advantages of surface drives:

http://www.seafury.co.nz/design_build.html

cheers
boogie

[san.dam]

Was on the market in Italy and Europe some years ago, a surface prop and bracket gear called LeviDrive.Have you ever heard? It was an half pipe (Korf,Kort...) around the half top of prop,a very captive cavitating prop.
Well,this half pipe steers and allow for manoeuvering. And the exhaust gases are projected on prop. Center of propeller in line with Keel line(in case one engine). A high effectiveness gear. Badly, as already said in thread, at low speed and general manoeuvering,the boat is quite insensible...even astern.
I built some years ago a 27 ft workboat 2500kg,equipped with this LeviDrive. The result was a 44kn max,with a VolvoPenta Turbodiesel 220 hp. Good enough...
The boat works even in our lagoons,where touch the ground in shallow water often occurs, and no problem of fatigue,even after years.
My opinion on the surface drive is good,but in evaluation we have to take in account it is vibration and noise,in last less comfort.
But fast.

Originally Posted by nemo

Hi, I attended a course at University about surface drives...
IMHO, these drives should be used on racing boats or patrol boats only...
the propeller itself hasn't got a better efficiency than a traditional one, and it suffers a lot of fatigue load, due to the continuos load/unload of the blades through water and air. A surface driven boat's owner should take in account that sooner or later he will have to change the propeller because it will brake.
.

Any boat owner should take into account that sooner or later he may have to change a propellor. Just run aground or hit something in the water!

I think that if a surface drive propellor manufacturer did not take into account the load/unload factors when designing and manufacturing his propellors, he would soon be out of business.

I have been operating an Arneson Drive vessel since 1991, averaging 300 hours a year. In that time, I have had only one propellor failure, which was attributed to a casting flaw. I will try to find a picture, scan it, and post it here. Because of the casting flaw, the propellor manufacturer made good on their product and replaced the propellor.

At this point I have been using the same set of wheels since 1992, NIBRAL 35x39 4-blade S-class wheels, I estimate they have 3500 hours operating time on them, and they are still running strong. Based on this, I dispute the assertion that surface piercing propellors have a shorter service life based on loading/unloading factors

[xrudi]

We have stared to produce Levi Drives In Malaysia. Please visite our webpage www.levidrives.com.

We have produced 3 models so far.

a) Levi 170 - 125, Levi 170 - 150
b) Levi 240 - 250
c) Levi 280 - 300

Here the explanation for the code 170 means = max prop 17 inch
-150 = means 1,5 inch shaft

Do you have any picture of your boat.

Cheers Capt. Rudi

Have you considered Q-SPD Surface drives.
We have a simple and effective solution
www.q-spd.com

[Janamon]

Hi. Seafury drives are fitted to a 45 deg transom which greatly improves astern movement. There exhaust also exits through the center of the drive which assists in the ventilation required to get the vessel up and planning. As for the propellers, they are designed to take the loading unloading. You can fill out an online inquiry. You must fill out all the fields on the page to get a good prediction. I found them very helpful. You can visit their web site. www.seafury.com