Direct drive to V drive conversion help

[Cripz0062]

Hi !

Sorry for my thread, purrist will hate me

I have a Riva junior hull (all wooden boat), with no engine and no transmission only the hull, as I have many job to do on the hull and as I can’t make it precisely like new, I want to put it in V drive setup to gain space in the cockpit and a bigger wave

Internet research don’t really help me, it’s pretty hard to find informations
I see flat bottom boat have champion or casale trans but with tranny behind the engine
It’s seems ZF 48 iv was a good thing

but how about to choise the ratio ? I would like to out an ls engine (300 - 350 hp)

regards

 

[Cripz0062]

 

[Cripz0062]

It weight 1 000kg in original configuration

 

[74 spectra20 v-drive]

That Vdrive is a big unit and if i am not mistaken the tournament boats that run vdrives move the engine from the middle of the boat to the rear. I think you would end up moving everything down to the strut. Most tournament ski boats run thru the Borg Warner Velvet drive they aren't the fastest things on the water but they shure work well. assuming you want the vdrive to try and get some more prop speed?

 

[Cripz0062]

That Vdrive is a big unit and if i am not mistaken the tournament boats that run vdrives move the engine from the middle of the boat to the rear. I think you would end up moving everything down to the strut. Most tournament ski boats run thru the Borg Warner Velvet drive they aren't the fastest things on the water but they shure work well. assuming you want the vdrive to try and get some more prop speed?

The borg warner seems to be big too ?

is that what I want, put the engine to the rear, it’s a 1960 wooden boat, I don’t necessarily want more speed, stock is 36 knot with less than 300hp, if I hit 40 kn with 350hp I will be happy

 

[74 spectra20 v-drive]

By the drawings you showed it has a mid engine right? The borg warner unit is half the size of that vdrive unit, it just a small transmission (forward - neutral - reverse) and it's what they run in the tournament boats, I run one in my flat bottom and Day Cruiser. They are roughly 90 lbs. I attached a link below, there are adaptors to increase ratios, I have never played with them or seen them and really don't think you would need it for a cruiser, also i attached a picture of a 63Cruszon mid engine boat with the velvet drive.

Velvet Drive Inline Transmissions | Velvet Drive 71 & 72 Series Inline Transmission

Buy Velvet Drive Transmissions at Trans Atlantic Diesels

www.tadiesels.com

 

[Cripz0062]

Thanks for your answer, precisions and the link !
Yes in the drawing the engine is in the middle of the boat, but I want to change the emplacement, I want to put the engine to the back and use a V-drive not a direct drive

when I search for borgwarner v-drive I find only big unit, I would like more than in drag boat

 

[74 spectra20 v-drive]

If you are moving the engine back you could run a conventional gear box then, with the freeboard in that boat i am sure you could cover most of the running gear with floors. My Day cruiser has everything under the floor...

 

[Cripz0062]

Great news, I take some measures, I will post few drawings when I have it done.

what you mean by « conventional gearbox »?

 

[Cripz0062]

Here my hull with the space the engine will take

I use LS with dry sump dimension

 

[Cripz0062]

If you are moving the engine back you could run a convention gear box then, with the freeboard in that boat i am sure you could cover most of the running gear with floors. My Day cruiser has everything under the floor...

Does you mean I can use a car transmission (TH700) and a 1:1 ratio vdrive ?

I have a TH700r4 in a old chevy K5

 

[snowboat]

His gears are probably too tall.

 

[Wheeler]

 

[Cripz0062]

Hi Wheeler, my Riva will be so cool with the same configuration, but Dangerous for girl's hairs haha, I know this will be cheaper for me to let the engine in direct drive (I can spent money on Stainless headers), but I want to gain space in the hull.

I have a WG DIV 71B-1 transmission, which mark and model it is ?

 

[74 spectra20 v-drive]

i was talking about a standard vdrive box, run a trans off the motor into a gear box.

 

[Cripz0062]

i was talking about a standard vdrive box, run a trans off the motor into a gear box.

Please can you say me a model you think can be good ? And the ratio ?

Sorry for my English I'm French, so you said I need = Engine + automatic trans + vdrive ?

Has snowboat said, my th700 may be too tall ?

 

[74 spectra20 v-drive]

Here are some pictures of my day cruiser, when I say standard it's the typical v-drive setup. If this boat is a cruiser with some basic power I would not get hung up on your trans ratios etc... Guys with big power like running a bigger trans so they can drop the boat into 1st gear in no wake zones, most of the time when running around the boat goes into drive and go. The gear box is where you gain your efficiencies and get that prop spinning, the gears have a wide range for type of boat, 10, 18,22, 29, 48 ++. My Day Cruiser runs 22's and my FlatBottoms runs 18's. I do run a transmission in both boats, it's a borg warner Velvet Drive 1:1 ratio and then multiplied once it hits the gear box

The only reason I suggested this was your statement of moving the engine to the back of the boat, the V-drive units that are compact and found on the tournament boats and pretty dam expensive if I am not mistaken, and by moving the engine I believe you will need to make changes to the strut anyway so why not go this way (I am just familiar with this as well) In my day cruiser everything less 4" of the top of the gearbox is under the floor so it's not taking up usable space in the boat.

 

[Cripz0062]

It’s really nice with your pictures !!

as I’m French some different words was the same thing for me, so
- the gearbox is the black transmission mounted on the engine ? It will do F-N-R, in your case it’s a BW 1:1 ratio (72C??)
- the transmission it’s the v-drive ? It was 1:1 ratio too ? What is the brand of yours ?
- when you say 18´s and 22’s it’s the size of your props ?

Thanks for your time

 

[74 spectra20 v-drive]

The Borg Warner Velvet drive transmission (1:1) is mounted to the engine, simple trans with a neutral - forward - reverse . The finned aluminum piece is the gear box.

Think about a real wheel drive vehicle... engine to trans to drive shaft to rear end to axels to tires. In a v-drive, instead of the rear end you have a gear box with an input shaft (from the engine) and an output shaft coupled to a prop shaft to the propeller. The gear box in the picture is a Champion box, i really like it but by far the most common is a Casale box., which I run in my Flat Bottom boat.

Also a transmission is not mandatory to make this work, see drawing below, there is no trans and this is quite common with the flatbottoms (see pic of my Sanger Flat Bottom not sure if i lost you with the fat bottom comments) with this you would take the boat in and out of gear at the gear box, you need to stop the engine to drop in gear as well. This is why I like the little transmission, all hydraulic in and out of gear and never turn the engine off.

The gear box is where you gain prop speed. Below is a list of all the variations of gears - you can get into a very deep discussion around gear boxes.
for a V-drive propeller sizes are in diameter and pitch of blade, for instance I run an 12 -16 on both my boats. 12 is the measurement of the prop across the bales and 16 in the pitch or inches the prop will move forward per revolution,.

Again this is 1 way to do this or you find the vdrive / gear box in 1 unit as you listed above.

 

[Cripz0062]

You are so helpful !
Yeah I understand what you mean, I don’t be afraid with mechanical words, I’m a mining workshop supervisor, mechanics is my passion but I don’t know boat particularity especially because of the prop

my boat will weight 1000kg, 350/400 hp (if possible I would like to hit 40kt or more) I want it good for wakesurfing, wakeboarding... (larger diameter, smaller pitch ?)
In comparaison yours boat goes faster and lighter ? Does 1:1 ratio will match my application ?

what’s setup was in malibu/mastercraft wakeboard boat ?I don’t find any information on internet...

 

[74 spectra20 v-drive]

My nephews have tournament boats for wake boarding, they have the same trans i have, the Borg Warner Velvet drive 1:1, should be just fine for your application.

 

[Cripz0062]

I have find a old transmission, it look like a velvet drive 71c, what do you think ?
this is a direct drive 1:1 ??
If it’s a 71c I will buy a rebuid kit and a bellhousing to fit the transmission on the engine, any ideas ?

 

[74 spectra20 v-drive]

The difference between the 71 and 72 is what horsepower they are rated for, I run the 72 and am well above the "Ratings" these things will handle up to 500HP and change with no problems, they do not like high rpms, I spun my flat up to 7K once and burned the pump up in the trans. (long story of why it spun to 7K ) If you stay with mild power you should be fine with the 71,

I would suggest searching for some shops that have experience with them and just double check the 71 capabilities.

The trans should have a tag on it, opposite side of what you posted in the picture, see the gold tag in the picture below, this has all the specs on the trans. A very nice feature of the velvet drive is that you can run counter rotating engines with them, the picture you have of the spline that unit with the 4 bolts is the pump, look to the top of it and you will see an arrow, that arrow should correlate with the rotation of you engine, to change all you do is pull the 4 bolts and rotate 180 and put the bolts back in. I note this because I had one rebuilt and never checked it, fired the boat up and had no trans, oops, slid the trans forward rotated it and fixed.

 

[Cripz0062]

I will look when I come back home Saturday, but I think does I Don't see anything at this place. The Caterpillar logo on the bolt make me think than this transmission have more than 30 years. How long ago Borg Warner make the 71C model ?

I'm looking into 350/400 HP 71C will match ?

Is that possible to upgrade a 71 to 72 ?

 

[Cripz0062]

The trans should have a tag on it, opposite side of what you posted in the picture, see the gold tag in the picture below, this has all the specs on the trans. A very nice feature of the velvet drive is that you can run counter rotating engines with them, the picture you have of the spline that unit with the 4 bolts is the pump, look to the top of it and you will see an arrow, that arrow should correlate with the rotation of you engine, to change all you do is pull the 4 bolts and rotate 180 and put the bolts back in. I note this because I had one rebuilt and never checked it, fired the boat up and had no trans, oops, slid the trans forward rotated it and fixed.

Yeah it's a think to know haha, when I see thèses marks I asked myself the question