green lightning

How can you say acceleration is slower ?

CDShack

I think he means 'hole shot'. Because they cavitate/ventilate when you hit the throttle, they are somewhat slower (depending on prop) than a sterndrive from a standing stop, but with a little practice, I got my Kaamas up within about a second of the sterndrive, but made up the distance fast!!! Acceleration once hooked up? Awesome!

Griff

Do you realize that the cost of doing the conversion to surface drives would cost more than the boat will ever be worth?? Like 40-50k???

green lightning

Most of the time when you hole shot a bravo drive with any kind of power you stop accelerating real quick

Alexanderlindahl

Haha! TOUCHÉ😂

That's why im running an xr drive with 310hp😂 full throttle sends!

justfishing

Surface drives are going to provide slower acceleration until the prop ventilates. A surface drive is meant to have half the prop out of water. So when the prop is submerged it is like starting a car in second gear. That is why you see vent tubes for some surface drives. It helps reduce the bite of the prop and is like putting it in low gear.

Surface drives are good for high speeds and efficiency

Fasterboatman

As you already have heard from this site, a lot of great feedback. Im in the middle of an installation of the 7m drives. But I have a big heavy boat that should never have come with bravos. 47', 19k lbs, and B3s. I choose the Arenesons as they reduce the need to alter the engine placement for those who are currently using a bravo variant. First, they are way expensive new and used! More than your boat may be worth, so keep this in mind. They are much more durable, but when they break, have some cash available. They are slow out of the hole, but you can add vent pipes to solve that. Props are not cheap! And you will add 54" of drive off your transom.
If your boat is weighs less than 5k PER DRIVE, I would suggest staying with bravo's (find some good X drives, or IMCOs, etc with the big prop shafts). Bravos are good as long as your boat is light enough. I had a 31' with twin B1s, and 502smags. Stepped on the mags a little with computers, injectors, and headers. Never had an issue, but she was a balsa cored hull and total dry weight was 5800 lbs. With that low of a drive loading, and a little bit of careful throttle action, I never had a drive issue. in 690 hours of fun. I even launched her a few times (whew, lucky me though). You can replace your Bravos a couple of times or even go with some of the bigger drives that are available and still beat the Arneson drive costs. For a big boat like mine, surface drives are the only real option. For you, please do your research.

Good luck!
jeff

green lightning

What is the example that you are using to compare the slower acceleration too ?

Drake22.250

iTrader: (2)

Arneson require a 18 inch prop to get on plane, I am happy with my set up.

CDShack

I reach up and get about 4k rpm. Mine start off ventilating, then one prop 'grabs' and drops RPM, so I throttle that side up and about that time the other prop 'grabs' and I throttle it up and away we go! I've got it down now, as I said, where I can fiddle and feel the boat and drives, and can come out of the hole pretty quick. Mine are Kaama, and I have several friends with them and they act the same. If you have Arneson's, I noticed several with the ventilator tubes. They may act differently.