Arneson surface drives

[gerard 7316]

Can anyone give me the pros and cons on running an offshore sportfisher with a pair of these?

 

[MikDee]

Re: Arneson surface drives

Well I'll give you my take on it, being a surface drive, with only 1/2 the prop in the water, you will lose some low end torque out of the hole, and when not planing, but if set up right you'll gain speed over conventional drives. It may not be as fuel efficient as these either, this factor maybe something to consider if going offshore.

 

[Dhadley]

Re: Arneson surface drives

On the hulls we've used them on they're very efficient. Nothing has been lost on the bottom end which wasn't really expected. However, they need to be on hulls that were intended for surface drives. Basically the hull should be a rocker bottom rather than have a hook.

They (obviously) put the prop back in very clean water and have almost no drag whatsoever. A very interesting design, an extremely intriguing man.

 

[MikDee]

Re: Arneson surface drives

On the hulls we've used them on they're very efficient. Nothing has been lost on the bottom end which wasn't really expected. However, they need to be on hulls that were intended for surface drives. Basically the hull should be a rocker bottom rather than have a hook.

They (obviously) put the prop back in very clean water and have almost no drag whatsoever. A very interesting design, an extremely intriguing man.

IMO, I don't know if there's a trim adjustment on these, but if not, when you use an oversize surface drive designed prop, that's 1/2 out of the water, the hole shot is affected, it takes longer to get on plane, then conventional systems.

 

[Dhadley]

Re: Arneson surface drives

They have a rather large trim cylinder. In fact different ones can be used on different applications for the same size drive. Because of the length of travel the prop can end up pretty far below the hull at full negative trim.

On the other hand the centerline of the propshaft on an outboard drag boat ends up even or slightly above the bottom and they lose nothing on the holeshot.

 

[MikDee]

Re: Arneson surface drives

I know it's not much of a comparison, but after a few years of racing Pro fast electric R/C boats, I have learned a bit more then the average rookie, about surface drives, the physical results are similar on these, compared to full size boats. The surface drive (readily available) hardware shown on this boat, I set up, along with the turn fin, & trim tabs, is used for right hand, oval sprint racing. The hole shot is slower then an inboard, or I/O boat, set up the same way, because the surface drive prop slips a lot more then a submerged prop on takeoff.

 

[ddaigle]

Re: Arneson surface drives

Mik, your toy boat doesnt have trim. Like DHadley said, with arnesons, you can bury the prop underwater on takeoff and trim it up as speed increases. Also, surface drives can run a higher pitch prop due to the reduction of drag, this fact might cause some lengthening of planing times but will increase speed and efficiency. Also, Dhadley has actual experience with these drives, as he said, to gain the most benefit it helps to have a hull designed for them. I have researched arnesons extensively and seen them in action and up close and personal as I wanted to buy one for my boat. They are a very quality product.

 

[MikDee]

Re: Arneson surface drives

Mik, your toy boat doesnt have trim.

I don't consider my $600 R/C boat a toy!

Like DHadley said, with arnesons, you can bury the prop underwater on takeoff and trim it up as speed increases. Also, surface drives can run a higher pitch prop due to the reduction of drag, this fact might cause some lengthening of planing times but will increase speed and efficiency.

I did mention mine was a fixed drive, I figured the Arnesons probably had hydraulic trim control, similar to the action of trim tabs,,, But with a fixed shaft there is a hesitation as the prop try's to grab water (spools up), that you don't get in a submerged prop. As I said, prop size, pitch, & design, is all the same info I was familiar with from setting up my R/C boats, it's really not much different, just on a smaller scale. (besides I never had the chance, opportunity, was in the position to, or had the money, to play with this on a full size scale) I am not putting DHadley down by no means, I consider him the expert on this, along with Walleyhed, and a few others here,,, I'm just a talking head here, or a talking "airhead" putting in my 2 cents for whatever it's worth,,,
because this subject fascinates me

Also, Dhadley has actual experience with these drives, as he said, to gain the most benefit it helps to have a hull designed for them. I have researched arnesons extensively and seen them in action and up close and personal as I wanted to buy one for my boat. They are a very quality product.

By the way, This is my 3 ft. long Fast Electric "toy" in action, I love the rooster tail:
http://smg.photobucket.com/albums/v240/MikDee/Model Boats/?action=view&current=FDM32Video.flv

 

[Dhadley]

Re: Arneson surface drives

Cool RC boat! The Arneson, and even the Kaama drives, were amazingly similar to that. The trim cylinder was anchored above the drive and the steering cylinder was to one side. That eliminated the need for the rudder. However there is a guy, and his name and the name of his drive escapes me at the moment - Harry something I think, making a system very similur to what you have. The shaft is fixed and it has a rudder. There's a box covering the drive that houses the rudder shaft.

 

[Dhadley]

Re: Arneson surface drives

Got interrupted -- anyway, that's the drawback to the fixed design (Harry Shoal maybe??), there isn't any trim. He relys on trim tabs for all the negative trim. Kinda like a straight inboard.

 

[MikDee]

Re: Arneson surface drives

Thanks DH, Without looking around, I recall what the Arneson drive looks like, now, it appeared odd to me, because it was not a tripod design? just one arm for trim, & one for steering, both hydraulic, a unique design to say the least, and that other drive you mentioned, I think I've seen it online searching out surface drives quite awhile ago.

My goal would be to convert my 19' Bayliner Ski boat with the 125hp Force motor to surface prop design one day maybe if possible, just for the fun of it, and of course some extra speed, and a killer roostertail! I'm just not sure how to go about it, maybe at some future date you could help me with this? I guess this may not be practical as I think about it, I don't think they make a surface drive prop, (a chopper, or cleaver), for a Force outboard

The R/C Offshore boat from the video:

 

[Dhadley]

Re: Arneson surface drives

Pulse Drive - Harry Schoell, that's it. It was driving me crazy. Looks like his latest design has the whole thing moving for trim. Platform & all.

Anyway, the conversion can be done but you need to consider the bottom design. If it has much of a hook it won't work as well as a rocker bottom. We converted a V-drive to surface drive and the bottom design was always a bump in the road. Shifting was too. We had a transmission on the motor which was about 1/2 in and 1/2 out of the transom. We built a box to house the part that stuck out and the Arneson was on the back of the box part. Just kinda made room so the transmission would fit without moving the motor forward. A wild ride when it was done.

 

[tommays]

Re: Arneson surface drives

I wonder what the merc BOLT_ON kit costs


There is a loy of forum talk about them at offshoreonly.com

Tommays

 

[QC]

Re: Arneson surface drives

You guys need to check this one out: Surfacing I/O thing

I have been watching it for a couple of years. I'd sure like to see a drive without two 90 degree turns . . . With a biiiiiig swimstep, could even be a farely clean installation.

 

[MikDee]

Re: Arneson surface drives

I wonder what the merc BOLT_ON kit costs


There is a loy of forum talk about them at offshoreonly.com

Tommays

Isn't that PURDY!!!

 

[Bondo]

Re: Arneson surface drives

My goal would be to convert my 19' Bilgeliner Ski boat with the 125hp Force motor to surface prop design one day

Ayuh,.... You'll have to excuse me,.... I've gotta go clean my 'puter screen,...
I just Spit all over it....

 

[Frank Acampora]

Re: Arneson surface drives

Well, Mik! Michigan did make a Cleaver prop for Chrysler with the Chrysler logo on it.

I have one --New old stock--Stainless, thinned blades--really thin, about as thick as a razor knife blade in some areas, and with a radical cup. Hit anything more hefty than grass on the water and there will be a major repair. 12 inch diam X 21 pitch. I would say it appears to have about 2/3 the area of the regular 12 3/8 diameter prop.

This prop was made for the one piece Chrysler lower unit and will also fit any 3 and 4 cylinder Force until Merc changed the lower unit.

I have one Nya-Nya -- and you can't have it.


BTW: having designed RC boats and airplanes, and having studied aircraft design at the Academy of Aeronautics, I can tell you that while the R/C "toys" are very similar to full sized in proportion, differences in scale cause different actions and reactions. SO: Just because a model performs one way, it doesn't necessarily mean that a full sized boat will react the same.

A simplistic example would be: It is very difficult to get the same power to weight ratio in a full sized vehicle as you have in a model. It is also very difficult to get a full sized engine to turn 20,000 RPM as in an alcohol/nitro fueled model. And while a scale model full race hydroplane might go 125 actual MPH on an oval circuit, the full sized race competition hydro will not be able to run laps at say, the 500 MPH scale equivalent.

 

[MikDee]

Re: Arneson surface drives

Ayuh,.... You'll have to excuse me,.... I've gotta go clean my 'puter screen,...
I just Spit all over it....

Well, I couldn't do this with my 20yrs of I/O's It's kinda nice getting back to a trailerable outboard boat. In case you didn't know, This boat is made like a Bayliner Cobra ski boat, built in pylon, & all, and unlike other Bayliners, it's tagged for 150hp! you think that's funny? I actually have my first 4-blade prop, it's a Piranha composite prop, that works great, and I found it actually gave me some bow lift. Plus I picked up a nice rare 3- Blade SS prop, reasonably priced that works fine also.

 

[MikDee]

Re: Arneson surface drives

Well, Mik! Michigan did make a Cleaver prop for Chrysler with the Chrysler logo on it.

I have one --New old stock--Stainless, thinned blades--really thin, about as thick as a razor knife blade in some areas, and with a radical cup. Hit anything more hefty than grass on the water and there will be a major repair. 12 inch diam X 21 pitch. I would say it appears to have about 2/3 the area of the regular 12 3/8 diameter prop.

This prop was made for the one piece Chrysler lower unit and will also fit any 3 and 4 cylinder Force until Merc changed the lower unit.

I have one Nya-Nya -- and you can't have it.

Sure, now ya got me droolin! So what do you want for it, an arm or a leg, or both?

BTW: having designed RC boats and airplanes, and having studied aircraft design at the Academy of Aeronautics, I can tell you that while the R/C "toys" are very similar to full sized in proportion, differences in scale cause different actions and reactions. SO: Just because a model performs one way, it doesn't necessarily mean that a full sized boat will react the same.

A simplistic example would be: It is very difficult to get the same power to weight ratio in a full sized vehicle as you have in a model. It is also very difficult to get a full sized engine to turn 20,000 RPM as in an alcohol/nitro fueled model. And while a scale model full race hydroplane might go 125 actual MPH on an oval circuit, the full sized race competition hydro will not be able to run laps at say, the 500 MPH scale equivalent.

Granted, I'm aware of all that, it goes without saying, but there definitely are some similaities, that's all I want to say. Surface drives are just an interesting subject to me. I'm sure you probably have a better grip on the subject then I do, from you're schooling, and the knowledge, & help you give with your posts, especially Chrysler, & Force related. I think you have some pretty cool toys yourself!

 

[Frank Acampora]

Re: Arneson surface drives

No, Mik. You can't have that prop. Not even if you gave me your first born male child. It is destined for my 1990 90HP. I'm going to jack the engine, install a low water pick-up, and run it 'till the reeds sound like a nest full of pissed-off hornets. I may also try a nose cone just to see if it makes a difference. But if things go correctly, the engine will be riding on the bottom of the torpedo so a nose cone should not make a difference.

That's actually my fun boat--my goof around boat--my experiment boat. Someday it's going to get the 125. Just to see what it will do.