V-Drive

[commander315]

Im looking at sea ray with "vdrive" inboards. What exactly is vdrive?

 

[Sharp Shooter]

Re: V-Drive

The "v" comes from the relationship between the driveshaft and propshaft. This is a flatbottom raceboat set up that clearly how it works. The gearbox is also referred to as a "v-drive".

 

[SangerTom]

Re: V-Drive

Inboard motor mounted in the stern of the boat with the propeller typically underneath the motor. To accomplish this the drive shaft goes forward (towards the bow) and the makes a "V" to come out with the prop facing the correct direction.

It gives you more room on board as oppossed to a direct drive, in which the motor is in the middle of the boat

 

[shwoop_soobie]

Re: V-Drive

i would be worried about siting next to the gears and drive-shaft... those things come apart and your gonna be picking chucks of burning metal out of your side...

 

[commander315]

Re: V-Drive

One more question, are they good setups? fast? efficient? etc..?

 

[25thmustang]

Re: V-Drive

My boat has Vdrives. It allows for a full cabin/aft cabin and inboards. I would bet they are less efficient then a straight inboard, but they seem to be fairly popular.

My boat is not fast, it is about as efficient as any 10K lb boat with twin 350s.

 

[arks]

Re: V-Drive

One more question, are they good setups? fast? efficient? etc..?

V-drives are common and builders use them to maximize cabin space. While fairly reliable, they are a little less efficient than straight inboards. Biggest problem with them in a big boat is usually poor access. They tend to put the engines directly above the stuffing boxes so maintenance and repair can be a nightmare.
My boat has straight-shaft inboards and I was able to remove/replace a transmission without pulling the engine. Can't do that with twin v-drives.

 

[livendive]

Re: V-Drive

The things I've read suggest v-drives are a bit less efficient than outdrives in terms of fuel burn and top speed. The big bonus is not having those expensive outdrives taking a saltwater & debris beating outside the hull...your only exposure outside the hull is your driveshafts and propellors. So, slightly less room inside the boat than a traditional I/O, and slightly slower, but at a substantial cost savings in maintenance and repairs.

 

[Sharp Shooter]

Re: V-Drive

One more question, are they good setups? fast? efficient? etc..?

They're great! Way more efficient than a basic direct drive because they offer a better (shallower) shaft angle.

There's only one propulsion system that has proven to be faster and that is Ken Warby's rocket lol. V-Drives are used to propel Unlimited Hydroplanes over 220 mph and Top fuel drag boats using twin shafts (W Drive) over 260 mph.

Stern drives are more common and allow easy trim adjustments, more interior room and a better reverse.


One of the guys mentions he would be scared the gear box may harm him. I grew up with v-drive boats (from diapers) and my line of work is filming race boats. I capture all kinds of crazyness on video. Even in extreme racing conditions I've never seen a v-drive gear gase come apart to the point where someone was injured. Some people are just rEdIiCuloUs...

 

[Aloysius]

Re: V-Drive

V drives may be slightly less efficient that straight inboards, but not much. Access/maintenance of the stuffing box is the problem. It also places the engines aft, which may or may not work for your particular hull.

The shaft angle is an interesting issue. Probably depends how far forward the v-drive is.

I can't imagine leaving an outdrive in the water full time. In salt water the maintenance can be overwhelming, not to mention there's only a rubber boot between you and the bottom of the ocean.

Me? I've got 2 straight inboards with direct drive velvet drives. REAL simple and easy to service.

 

[sasto]

Re: V-Drive

Shaft angle.........You have less shaft angle on that v-drive resulting in more efficiency and speed. We have built the same boat, same power, same weight, the v-drive outperfomed the straight drive in all aspects.

 

[Sharp Shooter]

Re: V-Drive

V drives may be slightly less efficient that straight inboards, but not much. Access/maintenance of the stuffing box is the problem. It also places the engines aft, which may or may not work for your particular hull.

If you mean a direct drive inboard you are incorrect.

The shaft angle is an interesting issue. Probably depends how far forward the v-drive is.

The shaft angle combined with the length of the propshaft determines where the boat rigger mounts the v-drive. The shallower the angle the more efficient the push.

 

[rallyart]

Re: V-Drive

A v-drive is often the same hull as a direct drive with the underwater gear being identical. The v-drive just puts the engine at the back instead of the middle. Inboards will not have the same top speed, or efficiency at high speed as an outboard or a sterndrive. They are usually more efficient at cruising speeds but a lot depends on the exact boat. V-drives are less of a risk for blowing apart than your connecting rods are.
Most ski or wakeboard specialty boats are D or V drives because the wake can be cleaner with this design.

 

[Sharp Shooter]

Re: V-Drive

A v-drive is often the same hull as a direct drive with the underwater gear being identical. The v-drive just puts the engine at the back instead of the middle.

Aside from select wakeboard boats this is simply not true.

Inboards will not have the same top speed, or efficiency at high speed as an outboard or a stern drive.

Outboards and stern drives share one key advantage over v-drives. They can trim for a perfect propeller angle. The outboard combined with a tunnel hull is a super efficient combo. The down side is, outboards have a very low ceiling when it comes to making power. Stack 3 300's on a transom and you still only have 900 hp.

The stern drives achilles heal is it can't handle big power. As I have stated previously, the worlds quickest and fastest boats (aside from 1 fighter jet powered boat) are v- or W-driven. This is fact not opinion.

They are usually more efficient at cruising speeds but a lot depends on the exact boat. V-drives are less of a risk for blowing apart than your connecting rods are.

I can agree with this one.

Most ski or wake board specialty boats are D or V drives because the wake can be cleaner with this design.

I think there's more to this. The bottom shape of the boat combined with the turn fins and rudder make these boats track the best regardless of who's in back trying to pull them off course. They also have a better ability to pull people up without the assist of trimming the prop. Another advantage over the out drive is having the underwater gear literally under the boat as opposed to hanging off the back. Call it a safety bonus.

 

[rallyart]

Re: V-Drive

Good point Sharp Shooter. Many V-drives are in race boats. In fact Sanger's experience with them led it to be the first V-drive production wakeboard boat.
In large boats the V drive is used to package the engine location and drive when a sterndrive or pod drive are not suitable. My simplified answer was misleading and would not apply to a Sea Ray yacht with a V-drive power supply.

 

[lkbum]

Re: V-Drive

Boating Magazine did an instrumented test on 31' SeaRay Sundancers (the boat is offered with V drive and I/O stern drives. They tested identical boats with both drives. The results may surpirse hardened V Drive guys ... From the aritcle
"The stern drive boat was appreciably faster, both at top end and out of the hole, where it also showed less bow rise. In addition, our tests showed that, on average, the stern drive accelerated 20 percent faster from 0 to 30 mph. And it responded more quickly at following sea speeds - where you accelerate to the crest of a wave, then throttle back on its face - of 15 to 25 mph."

Here is a link to the article, it goes on for three pages and is excellent in comparing the two drive types. http://www.boatingmag.com/drive-train-boogie?page=0,0

Selecting a V Drive has obivous advantages, but speed and fuel efficiency are not.

 

[Sharp Shooter]

Re: V-Drive

Boating Magazine did an instrumented test on 31' SeaRay Sundancers (the boat is offered with V drive and I/O stern drives. They tested identical boats with both drives. The results may surpirse hardened V Drive guys ... From the aritcle
"The stern drive boat was appreciably faster, both at top end and out of the hole, where it also showed less bow rise. In addition, our tests showed that, on average, the stern drive accelerated 20 percent faster from 0 to 30 mph. And it responded more quickly at following sea speeds - where you accelerate to the crest of a wave, then throttle back on its face - of 15 to 25 mph."

Here is a link to the article, it goes on for three pages and is excellent in comparing the two drive types. http://www.boatingmag.com/drive-train-boogie?page=0,0

Selecting a V Drive has obivous advantages, but speed and fuel efficiency are not.

Those tug boats weren't built for speed and the v-drive boat they used is crippled by an inefficient 12 degree shaft angle...Gear selection plays a big part in the equation as do propellers. I seriosly doubt Sea Ray did much research when it comes to squeezing the most performance out of either of those luxo cruisers.


Show me a stern drive that can beat either of these types of V-Drive boats and I'll jump ship.

 

[25thmustang]

Re: V-Drive

Interesting article. I avoided stern drives due to cost. I know a sterndrive boat set up like mine would be faster and more efficient (I assume at least), but I enjoy not having those two extra mechanical devices sitting in the drink all day/night long.

 

[lkbum]

Re: V-Drive

Those tug boats weren't built for speed and the v-drive boat they used is crippled by an inefficient 12 degree shaft angle...Gear selection plays a big part in the equation as do propellers. I seriosly doubt Sea Ray did much research when it comes to squeezing the most performance out of either of those luxo cruisers.

You've got a lot to learn about boat R&D especially Sea Ray's efforts.

 

[sasto]

Re: V-Drive

Those tug boats weren't built for speed and the v-drive boat they used is crippled by an inefficient 12 degree shaft angle.

12 degree shaft angle on a v-drive, not a good test. We got 11 out of a straight drive on a 65' sportfish, switched to v-drive with a shaft angle of 8 degrees........same boat, same power.......8kts. faster along with better fuel economy. We are talking about a 55 ton fishin' battlewaggon. I find it amazing that Sea Ray, or any builder, would do a test, find it unacceptable, and build them anyway. Like somebody else already said: my opinion is worth what you paid to be on iboats.