Bravo to surface drives
 

Anyone done a swap from Bravo to surface drives? What issues - handling, performance, etc. - have you run into the most?

Probably need to be more specific with the boat. Single engine or twins, cat or v bottom, notched transom or not. There's a ton of factors

I just turned my Bravo drive into a surface drive. The bullet is just on top of the water at speed.

Twin engine V bottom set up on a heavy hull.

How did you do that? Shorties?

I converted my boat from bravos to arneson surface drives , handling was the same , performance i gained over 10mph , took a bit to learn how to get it on plan , the only problem that I ran into was the lack of used props in my range that I wanted to try and test

I also just finished my 3rd season with no drive problems , I could never say that when I ran the bravos

I am in the process of converting from Bravos to Arnesons also. I am going through the same problem with finding props to test before I purchase. How were you able to solve your problem of finding props to test ?

what boat are you running them on? What were the planning issues? What size prop are you running? I've heard the larger the diameter the better.

I have a older 35 straight bottom fountain , you can't ease it up on plan like i could with the bravos , my current props are 5 blade 18x31x20rake ,I think my props are a 1/2" to big in dia

What I did was found some cheaper 4 blade props to get idea on the pitch and then got set of 5 blades to help it get on plan

Raised the engine 1 1/8 th inch and added -3 IMCO shorties.
Getting on plane with 4 blade Bravo props was impossible without a little Tinkering.
No problems now at all.
I am running a 26 Daytona that only weighs 4500 lbs.

what boat did you do the conversion in?

There is a thread in the Velocity section where a Velocity 390 is be converted from XR to Arneson.

Padraig

I thought BBlades use to have a testing program. I did not use them and what worked best were 18x31-18. My first set of Herrings are my back up.

When I was looking for test props he did not have many #6 props with a dia, larger than 17 the only one with a large selection was cobra and he wanted $9500 to get in the program .

I spoke with Bblades and they do not have anything available in the 18" diameter props for testing.

I converted my 1994 38 foot Cigarette Top Gun with ASD7M drives, which is over 13000lbs with gas. If your boat weighs as much as mine, don't waste your money on 4 blades. I have Hering 5 blade, 18 Diameter, 18 Rake, 28 Pitch Props.with twin 610hp supercharged engines. They work pretty good. I am under pitched a little bit. I would love to try some 6 blades, but there are none to be found. You will most likely have to do what I did, which is purchase props and hope you get it right.

Yes. It is for sale and pop yachts is trying to sell it on many websites. We only used it once since Hurricane Harvey and it is running strong. We took a big financial hit from Harvey and my home is still not 100% complete. I don't really want to sell the boat and I may be taking if off the market.

Urban Disturbance and Green Lightening,
Any regrets converting to Arneson? Seems, from what Ive read, dialing in props is the biggest challenge, as there is no real efficient test program out there. Is the installation process a basic unbolt old transoms and bolt on Arnesons?

Got Cigs,

I have the Arneson ASD7M drives, and it was not a simple bolt on project. We had to pull and move the engines down and forward. which caused the Arneson bell housing to hit the stringers. So we had to do a little modifications to the stringers and engine mounts. Lucky for me, I did not have to replace my oil pans because I do not have huge ones. You have to cut larger holes in the transom so the transmission will fit and have access to the transmission fluid dip stick. 3 or 4 hydraulic hoses have to be ran to the helm because the steering control module is located behind the steering wheel. The entire steering hydraulic system has to be re-plumbed with hoses, fittings, cooler, reservoir and filter so if one engine dies, you can steer with one engine running. You need sea strainers, water pickups, water pressure pop up valves, ball valves, hoses and fittings for the cooling system. You will need a transmission cooler. I used one dual cooler for my transmission and steering for each engine. I do not have any regrets with the setup. If I was to purchase another boat and I had the option of Arneson vs. Bravo drives, I would pick the Arneson drives. They are bullet proof unless you hit something. Dialing in the props is a challenge.

The only regret I have is not doing the conversion 4 bravo's earlier . The installation of the 7m kits for me was not super difficult , as long as you have good basic mechanical skills and access to some sort of a lift to be able to pull the motors and transmissions in and out , I had to do it several times to clearance the stringers . I was involved with the installation of several of the kits so I knew what to expect .If yon have a full hydraulic steering system all you have to change is the helm . Dialing in the props is just a cost and how much you want to spend to maximize your performance . Also if you don't have the ability to do the installation my friend has a shop in Syracuse and he gets like $5000 to do the installation .

https://cimg0.ibsrv.net/gimg/www.off...153462bd41.jpg
With the jig set up you drill the transom for the studs on the extension boxes and cut out the center of the jig for the transmission .

https://cimg4.ibsrv.net/gimg/www.off...358daf97ee.jpg
Test fit the boxes and you are almost there

Thank you both for the real world information. What kind of speed gains did you guys see with the swap?

I did gain over 10mph but to be honest , every time I went out and was testing I would break the gears in my bravo1's that got expensive so I stopped , did the conversion and never looked back.

Wow! What kind of power do you have and is your boat a straight hull or stepped?

https://cimg1.ibsrv.net/gimg/www.off...c820aabe6f.jpg
I have a 35 straight bottom fountain with 517's and centrifugal super chargers they make around 775hp

^^^ Very nice. How do the Arnesons handle in big water?

Also, hope the OP doesn't think I hijacked the thread. Figured the questions were relative to the thread, so I asked away. Been tossing the idea around myself.

No problem I can hold it wide open all I want , I have not broken anything in the drives so far .

I am running a 38 foot Cigarette Top Gun strait bottom with notched transom. Twin supercharged roller engines around 610hp each. Props are Hering 5 Blade, 18 Diameter, 28 Pitch, 18 Rake. I am under pitched and could use Green Lighnings props. Because of not having the perfect prop, I do not know my full potential speed gain. I gained 8 mph with my current props but had to pull back the throttles because of the RPMS kept on climbing beyond 5500rpm. I pulled the throttle back when I hit 5650 rpm. If I had the perfect prop, I would think I could get at least a 12 mph gain at WOT in good choppy conditions.

https://youtu.be/Of1RY4M8VqM

Not quite a “surface drive”, maybe semi surface but I have an a imco scx-4 .25” below the bottom of my boat. Leading edge of prop blades are about 44” from the edge of the pad where the water begins to rise. Only disadvantage I’d say would be torque steer but that is fixable with a torque tab and that only applies to a single. Oh and all the money spent, time spent driving to get props, shipping props, testing props etc. lol all to be expected, first world problems.

Overall my boat feels better than it did with the drive just two inches lower, better trim, handling at all speeds. I’ve ran many different kinds of props and all seem to work good, except for a 4 blade bravo but that felt lame with the drive 4” deeper. The five blades work much better now than they did 2” deeper. If you’re serious about it you can make it work but as these other guys will tell you as well it’s a lot of effort, money, and a slippery slope.

Real good info guys! Were your speed gains with just bravo/Arneson swap, or was there some HP added too? Also, being that the motors had to be mounted a little lower, did that effect how your exhaust lines up? And one more question, being that these have a transmission, do they shift smoother in and out of gear, like a TRS?

I added wedges to my exhaust and used my existing holes . With the transmissions they shift in and out of gear a lot smoother than the bravos .