What is a "V" drive ?

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Pilotpak

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From time to time, I see a few references to "V" drives on this forum.

What is "V" drive, and are they really as problematic as some comments indicate ? (I tried a web search, and all I can find are some references to an engine with the drive shaft going forward instead of aft)

Thanks,
Wayne Larson 310 Cabrio
 
It's basically a gear assembly that allows the front of the engines to face aft for placement in boats where the engines are mounted in or I should say under the cockpit and not in the salon. I haven't had any problems with my 13 year old units but I did upgrade to higher horsepower units this year when I installed my new 8.1L HO's. The old drives were not rated for the new horsepower. I am not sure if it was a particular drive used in some older SeaRays that gave the drives a bad name. My V drives were made by Hurth. Take care. Bill
 
The "V" comes from the angle of the crank shaft relative to the prop shaft. The crank points towards the bow of the boat. Through gearing, the power is redirected to the prop shaft which points down and out the bottom of the hull towards the stern. Hence the term, "<" drive.
 
yup, inboards are either st drive with the engines forward under the salon with st shaft from the transmission to the prop or "V" drive with engines aft under the cockpit, engines face aft with shaft running forward then aft, hence "V" drive. St shafts are less complicated and supposedly have less potential for problems. Also with engines forward under the salon there is probably an advantage to performance etc.
 
The biggest "problem" with v drives is not reliability, but what they do to the location of the engine (s). They are used to get more living space under the helm. This is freed up by moving all that engine weight to the back of the boat. The ideal position should be toward the middle of the boat for balance and handling. So it's a compromise-space over handling. There are also many more moving parts which means higher maintenance costs than a straight inboard set up.
 
Vee drives are like conventional inboard transmissions except that the output shaft is under the input shaft. It's called a Vee drive because the power path is shaped like Vee, well a vee on its side... so maybe it shoudl be called Arrow drive... :-)

it allows builders to place the engines under the cockpit freeing the space under the cabin in the middle of the boat, without resorting to stern drives.

the downside is that the stuffing boxes are under the engines making maintenance and re packing difficult, so nowadays all builders use dripless packing glands.

Another issue is that it places a lot of weight near the rear of the boat, sometimes resulting in high bow when getting on plane. overall, Vee drives boats are not as fast and fuel efficient as sterndrives, but reduce mainteance and lack of corrosion issues make up for it.

They are pretty reliable... I think most of the problem you've seen mentioned must have been related to a bad series Merc/Velvet drive had between 98 and 2002. Most have been replaced by now and Vee drives require less maintenance than stern drives
 
It wasn't just merc/ velvet drive issues, Crusader had the same problems with those Borg Warner units in those years.
 
While I'd prefer st drives to V for all the reasons mentioned above, a boat with v drives would not be a deal breaker for me as they are reliable if cared for properly and serviced as per schedule. I just don't want to ever look at stern drives again!
 
it is not the v drive that I dont like but the far aft position of the engine weight they allow
 
I had v drives in a 28' boat years ago. Reliability/ maintenance was not an issue , but handling /performance definitely was. As so many have mentioned here, the placement of the engines so far aft made getting on plane and running a sloppy inlet a chore. That being said, if maximizing salon/living space is more important than handling etc, I dont see any reliability issues that would stand in your way.
 
not all v-drive installations have the motors under the rear cockpit......my Carver has the motors installed under the salon for optimal handling and planing - but they are v-drives...........the rear cockpit area has the gen-set, hot water tank and fresh water tank installed....
 
quote:
Originally posted by zolna

not all v-drive installations have the motors under the rear cockpit......my Carver has the motors installed under the salon for optimal handling and planing - but they are v-drives...........the rear cockpit area has the gen-set, hot water tank and fresh water tank installed....

Click to expand...


Sounds like a nice set up from a weight and balance point of view. Ease of access for routine service should be better as well.
 
i'm not sure i inderstand the benefit of using Vee drives under the saloon. you probably need to keep the engine higher to leave room for the shaft under the engines and you're still limiting access to the stuffing box. With the engines under the saloon, you may as well using straight shaft.

what am I missing ?
 
You'll also see V-drives (versus straight-) in inboard ski boats - specifically tournament wakeboard boats. One benefit is the gearing (much like a transfer case in a 4x4, ie - low-range) reduction...this allows you to pull a weighted wakeboard boat and rider up on plane much easier. Some drag boats run V-drives, etc....
 
Pascal.....I don't think you are "missing" anything......my prinary reason for the post was to indicate that there are v-drive set-ups which do place the motors mid-ship for optimal handling....the benfits vs cons in straight vs v-drive are always debateable......personaally I think the new ips drives are the only ones that really have it right......

the engines in fact do sit higher due to the shaft cossing underneath....but in my case I have dripless packings so there is little to no regular maintenance..I also do think the v-drives are more complex do to the need to "reverse" the drive......however, with the front of the motors facing the stern I have all kinds of room to service the water pumps, serpentine belts and accessories......
 
Hmmmm, V drives with dripless shaft seals. That might be a recipe for disaster if one fails.
 
Capt. Buddha, you are correct that tournament wakeboard boats are v-drives, but the main reason is so that the weight is in the back of the boat to throw big wakes. Gear reduction can be done with a straight drive also.

Being a direct drive waterskier who likes the water smooth, I'm not a big fan.
 
BTW - you also get a TON of room with a v-drive boarding boat (over the clamshell-style) direct-drive...used to have a Malibu VLX (v-drive)...weight in the back is nice for wakeboarding...but you also need to weight the whole boat, hence the ballast systems (stern, mid, bow), to get a world-class wake.
 
Thanks Guys,

That explains it all (I kind of had a picture in my mind that a "V" drive might have been One Engine Driving Two Props (or Vice Versa).

Wayne
 
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