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View Full Version : A direct drive type "speed boat" question.


Upper Michigan Prostar190
08-15-2007, 05:08 PM
OK, here is a question for everyone. I think there are definite advantagest to inboard boats. I have owned I/O's and I dislike them. so I am talking up the advantages of direct drives to my friend who likes larger, cruising type boats. Has MasterCraft ever produced any speed boats or cruising boats with longer, off shore racing style hulls? or even Kind of a hybrid of a speed boat/ cruiser??? I just thought the concept of a speed boat, or speed/cruiser with a direct drive would be awesome without having a I/O in it. whats your thoughts on this???:confused:

rodltg2
08-15-2007, 05:16 PM
what are you thinkg UMP???:D MC makes ski/wake boats not offshore boats.... :confused:

Monte
08-15-2007, 05:21 PM
OK, here is a question for everyone. I think there are definite advantagest to inboard boats. I have owned I/O's and I dislike them. so I am talking up the advantages of direct drives to my friend who likes larger, cruising type boats. Has MasterCraft ever produced any speed boats or cruising boats with longer, off shore racing style hulls? or even Kind of a hybrid of a speed boat/ cruiser??? I just thought the concept of a speed boat, or speed/cruiser with a direct drive would be awesome without having a I/O in it. whats your thoughts on this???:confused:


You could always show him one of those Maristar 240sc's.. Those suckers are HUGE.. with a cuddy cabin to boot...

Chicago190
08-15-2007, 05:32 PM
I like inboards, but I think there are advantages to sterndrives when it comes to larger boats especially high performance ones.

"Performance with sterndrives is better than inboards, since the propeller is pushing the boat at an optimum angle for speed or acceleration depending on the trim angle of the drive. (Inboards have an inherent loss of propulsion force because of the angle of the prop shaft.)"

fintek9
08-15-2007, 06:02 PM
Heck, I think the x-80 fits that bill! Over 28 ft long with twin 700 hp engines!!! The gentleman that traded in my x-star drove out with one of those! 120k plus he paid for it! after all the accessory's and up grades.......Now that's a cruiser!

Sodar
08-15-2007, 06:05 PM
Well, there are so many reason I/O's are used in place of inboards, but the main reason is bow lift and like Chicago190 said, loss of power through the shaft angle. I have been on a 51' Fountain with triple inboards. The boat had a lot of handling problems, but the biggest problem was with the boats bow steer.

The only boats that inboards and direct drive shafts have worked well in have been the catamarans. Boats like MTI, Skater and Nortech have all made this work, but the reason it has is because cats have an inherent bow rise with a air entrapment tunnel. Also, due to the design of a cat, the shaft angle is able to be run at a much less dramatic angle, than a v-drive... like this boat.
http://www.amfoffshoreracing.com/media/photos/2007/hollywoodfl/freezeframe/IMG_7694.jpg

Right now, the latest and greatest in durability, reliability and drivability are the surface drives, however even these are not perfect. Issues arise such as dockside manner (reverse sucks), planing the boat out is tough and requires large trim tabs and they are EXPENSIVE... you can buy two #6 drives for the cost of one Arneson Surface drive.

If you want a go fast boat... look elsewhere. MC makes a good ski boat, but they are a production boat.... nothing special about them. The realm of custom, high performance boats have been doing all this for a LONG time and have tried every trick in the book!

Mag_Red
08-15-2007, 06:10 PM
ya see UMP, with a speed boat, or as you Yoopers say, an off-shore type hull, the object is to get the hull out of the water. Less wetted surface= less drag= more speed! ( you following me son???) with the drives behind the hull, you are able to get more of the hull out of the water and yet still have your props in the water. ( you see.....if the prop ain't in the water doing it's thing....you ain't getting any forward motion. ) Now there is another type drive called an Arneson surface drive which is the best of both worlds.......a direct drive with the trim capabilities of an I/O. http://www.arneson-industries.com/products/asd16/DSC02321[1]_small.jpg

Mag_Red
08-15-2007, 06:11 PM
:rant: Dam it Sodar........ya beat me to it!!!!!!!!!!!!!!

6ballsisall
08-15-2007, 06:11 PM
Sodar, do you have any pics of these arneson drives? I've heard about them but never seen one before.

Mag_Red
08-15-2007, 06:13 PM
Sodar, do you have any pics of these arneson drives? I've heard about them but never seen one before.:rolleyes: Very funny Jeff!:D

M-Funf
08-15-2007, 06:14 PM
Like this?

Inboard..................................I/O............................................Jet.. ..................................Surface

http://www.arneson-industries.com/products/drives/Comparisons.jpg

Sodar
08-15-2007, 06:18 PM
Sodar, do you have any pics of these arneson drives? I've heard about them but never seen one before.

This is the conversion kit they have for the Bravo Mercury Drives. I have heard that it can be put on very easily, however the motors need to be shifted forward a foot or so to make room for the shiftable transmission.

Sodar
08-15-2007, 06:21 PM
http://www.arneson-industries.com/products/asd16/DSC02321[1]_small.jpg

See how this boat has a conventional shaft and rudder? My guess is that this boat is a commercial tour boat or something that needs to have some dockside manners and then for high speed passes they use the surface drives.

6ballsisall
08-15-2007, 06:23 PM
This is the conversion kit they have for the Bravo Mercury Drives. I have heard that it can be put on very easily, however the motors need to be shifted forward a foot or so to make room for the shiftable transmission.


Very cool looking Sodar thanks! Whats the plastic cover in front of the props for?
So these outdrives have gears???

Sodar
08-15-2007, 06:27 PM
Very cool looking Sodar thanks! Whats the plastic cover in front of the props for?
So these outdrives have gears???

Just so no one falls into the cleaver props. This things are sharper than a razor blade and EXPENSIVE!! A prop can cost as much as a new X2!!

milkmania
08-15-2007, 11:04 PM
on the twin engine x-80 and other twin engine boats....

1) does the engine/prop rotate in opposite directions?

2) if so, do they rotate inward or outward?

3) also, if they rotate opposite.... why? cavitation? prop wash? what?

4) do the engines rotate differently,or is it done through the transmission?

milkmania
08-15-2007, 11:07 PM
Just so no one falls into the cleaver props. This things are sharper than a razor blade and EXPENSIVE!! A prop can cost as much as a new X2!!

:eek3: I wouldn't want someone to fall into my prop either!!!!

good way to ruin a good prop:rolleyes:

shepherd
08-16-2007, 12:23 AM
One advantage with the I/Os that nobody mentioned yet is that you are less likely to cause major damage if you run aground or strike a submerged object. I'll never go exploring on the lake in my dd Mastercraft for fear I'd hit something and bend my shaft, strut, etc. If you run aground with an I/O, you just trim it up and float it off. I hit a big log once in my old I/O boat and the only real damage was my prop got chewed up (and the paint on my outdrive got scratched). Plus, even with my large I/O cruiser, it is nice to be able to trim up the drives and run her up on the beach.

shepherd
08-16-2007, 12:28 AM
on the twin engine x-80 and other twin engine boats....


3) also, if they rotate opposite.... why? cavitation? prop wash? what?

4) do the engines rotate differently,or is it done through the transmission?

Preferably, they would rotate opposite. My old Formula has twin props that rotate the same direction. The problem is that I can't take my hand off the wheel for a second without the boat doing a dangerous power turn due to the torque from the two props spinning in the same direction. Opposite rotating props would reduce or eliminate that problem.

I believe the engines rotate the same - at least in the Mercruisers - the gears in the outdrives are opposite.

Upper Michigan Prostar190
08-16-2007, 08:50 AM
Interesting stuff! :popcorn: Thanks for all the info! I just thought that a DD would make more sense, but for that application it just dont work better I guess. I dont really care much for I/O's so I was just curious if they made DD cruisers.

Upper Michigan Prostar190
08-16-2007, 08:52 AM
OH yea, and BTW, If I was to ever get a "cruising" boat instead of a ski boat, I would certainly look at those bigger Maristars to get the shaft through hull instead of an I/O boat. Those Maristars are dayum nice cruisers!

ProTour X9
08-16-2007, 09:04 AM
You could always try a CSX 265.

shepherd
08-16-2007, 09:04 AM
I recently sold my Formula. When I buy my next cruiser (in a few years?) it will have one or two I/Os, an extra large cockpit with sunpad, a cabin, and an enclosed head with holding tank. Oh yeah, and rod holders :rolleyes:

Sodar
08-16-2007, 10:10 AM
I recently sold my Formula. When I buy my next cruiser (in a few years?) it will have one or two I/Os, an extra large cockpit with sunpad, a cabin, and an enclosed head with holding tank. Oh yeah, and rod holders :rolleyes:

Why would you get outdrives in a cruiser? I/O's are pretty much good for very little.... especially on a large cruiser type boat that is used in salt. The biggest problem with outdrives in salt is corrosion and electrolysis.... salt water eats them up, unless you are VERY diligent in changing your anodes out and have a solid, well designed bonding system. The problem being is that the alloy used on outdrive cases is very soft in the scheme of things and is the first to be attacked. The second problem is handling in a large cruiser with outdrives is quite a bit more difficult than inboards with twin screws.

Every year, my neighbor hires me to drive for his annual Christmas cruise on his 37' Formula Super Sport and I am always amazed at how crappy it handles in slow speed manuvering. I literally feel more comfortable moving a 70' sportfisher around in the same amount of space as my neighbor's 37'er.... it is just a true slug! I love the ability in a twin screw boat to leave the wheel alone and get everything done with two shift levers and a little throttle. Having to spin the wheel on an I/O is just annoying!

shepherd
08-16-2007, 11:45 AM
Sodar,
You make very good points, especially with respect to the maintenance/corrosion problems with outdrives. I guess I'm just used to outdrives and the ability to trim them. I've never owned an inboard other than my MCs which are crap to maneuver at low speed. Plus, 90% of the boats in the size range I was thinking about have outdrives. We have a lot of shallow water around here, so my previous post about groundings, etc. is still valid.

It's a tradeoff, but I can see how the easier maintenance and maneuverability (for twin screws) make inboards an attractive option.

I'll stand by my holding tank recommendation though. I hate those portable toilets!

peason
08-16-2007, 12:01 PM
UMP - When you say cruiser, what are you talking about? My father-in-law used to have a 34' Sea Ray that had twin inboards, it was a nice sporty looking boat, he wanted more space so he moved into a 38' Carver that had a fly bridge. You can turn these twin screw boats on a dime, of course the really big ones have bow thrusters so you can parallel park.

Sodar
08-16-2007, 12:06 PM
Sodar,
You make very good points, especially with respect to the maintenance/corrosion problems with outdrives. I guess I'm just used to outdrives and the ability to trim them. I've never owned an inboard other than my MCs which are crap to maneuver at low speed. Plus, 90% of the boats in the size range I was thinking about have outdrives. We have a lot of shallow water around here, so my previous post about groundings, etc. is still valid.

It's a tradeoff, but I can see how the easier maintenance and maneuverability (for twin screws) make inboards an attractive option.

I'll stand by my holding tank recommendation though. I hate those portable toilets!

Yeah, where you are, shallows are always a problem. They have made improvements in inboard design over the last decade or so by providing prop tunnels and such. Ya know the weird thing though? My neighbors Bravo 3 do not trim all the way up, there is only about 4 inches of trimability in them and there is not trailer trim, to lift them all the way up to reduce draft or put the boat on the trailer! I know this because they had to pull the boat out at the shipyard when my neighbor wrapped a dockline and ruined his prop hub. I wonder if this is a new design for I/0's? :confused:

Sodar
08-16-2007, 12:27 PM
UMP - When you say cruiser, what are you talking about? My father-in-law used to have a 34' Sea Ray that had twin inboards, it was a nice sporty looking boat, he wanted more space so he moved into a 38' Carver that had a fly bridge. You can turn these twin screw boats on a dime, of course the really big ones have bow thrusters so you can parallel park.

Bow thrusters are for men who drink Espresso, wear tight paints and dress in pink!!

Upper Michigan Prostar190
08-16-2007, 12:46 PM
Bow thrusters are for men who drink Espresso, wear tight paints and dress in pink!!
:uglyhamme

Where did you see Hoosier Bob???? :D

Upper Michigan Prostar190
08-16-2007, 12:47 PM
UMP - When you say cruiser, what are you talking about? My father-in-law used to have a 34' Sea Ray that had twin inboards, it was a nice sporty looking boat, he wanted more space so he moved into a 38' Carver that had a fly bridge. You can turn these twin screw boats on a dime, of course the really big ones have bow thrusters so you can parallel park.
I meant a speedboat type. long bow, fast boat. that kind.

Sodar
08-16-2007, 12:51 PM
:uglyhamme

Where did you see Hoosier Bob???? :D

He was on "Big Gay Al's, Big Gay Boat Ride"


http://www.planearium2.de/pics/pics-104-6.jpg

Upper Michigan Prostar190
08-16-2007, 12:53 PM
He was on "Big Gay Al's, Big Gay Boat Ride"



:uglyhamme:uglyhamme You Rule!!!! :uglyhamme:uglyhamme WAY TOO FUNNY!!!

shepherd
08-16-2007, 01:05 PM
He was on "Big Gay Al's, Big Gay Boat Ride"



LOL! :uglyhamme
That is one of my all time favorite classic episodes.

"Dude, your dog is gay!" 8p