Viper Comparison to the J70

[Justin Scott]

The J70 is a great boat.

I only post this, just to correct any misperceptions about where the Viper stands in comparison.

Sure the Viper is faster BUT the Viper is not all about speed. The #1 design objective of the Viper was to make it "easy to sail". The Viper is uniquely controlled by a non-profit Class Association and the mission of the Class Association was to make performance sport boat sailing accessible to everyone.

Accessible meant a high stability ratio. The Viper would be a lot faster with a smaller keel bulb. I would venture that the stability ratio of the Viper is as high as the J70, and probably has a higher initial stability ratio.

Accessible meant a really simple carbon rig with just three tune settings. If you can sail a Laser/J22/Sunfish, you can sail a Viper. It's a "sheet in and keep your head out of the boat" concept.

Accessible meant legs in - easy- low athletic hiking. A high initial stability ratio and super wide tanks means comfortable hiking position for the "young at heart" with old knees.

Accessible meant an easy spin launching system with bow launch, single line halyard/retrieval system and no tack line to trim. There are only two lines. One line pulls the chute up and the same line pulls it back into the throat. The second line extends the pole. It can be done by one person, which is why the Viper can easily be sailed by two. It means no back stay, no twing lines, no fore and aft adjustment of shroud positions, no side to side adjustment of jib cars, no adjustable head stay and above all an overriding emphasis on simplicity.

Accessible meant "nobody can be paid to sail on a Viper"

Accessible meant a price point for a new boat, ready to race, with sails, trailer and cover of under $35,000.

The three biggest differences between a Viper and the J70 are

1. The J70 has a cabin. The Viper was always intended as an open boat for day racing.
2. The Viper is a lot lighter than the J70. That is largely due to #1 and partly due to construction technology
3. The Viper is legs in as opposed to legs out hiking.

As a result, the Viper is faster, but I agree with all those who say that speed is not the sole objective. Fun, one design sailing is the objective. Both classes have reached critical mass and both will deliver that in a somewhat different but good way.

[Charlie Visser]

I would add:

Force=Mass*Acceleration   F=MA
Assume Fv=Fj (assume Viper and J70 sail plans generate equivalent forward thrust)
Mv=750+475= 1225 lb
Mj=1750+700= 2450 lb
So, Mv=0.5Mj
Acceleration Av=2Aj
Estimated Av>2.5Aj (accounting for J70 greater hull drag)
With equivalent sail forces, Viper accelerates nearly three times faster than J70.
Fun=f(A) (Acceleration is fun.)
Therefore, Funv>2.5Funj

Example: take a sharp puff in the Viper and accelerate from 6 to 12 knots in 3 seconds. J70 takes 8 seconds.

[Dan Tucker]

I would add:

Force=Mass*Acceleration   F=MA
Assume Fv=Fj (assume Viper and J70 sail plans generate equivalent forward thrust)
Mv=750 lb
Mj=1750 lb
So, Mv=0.43Mj
Acceleration Av=2.3Aj
Estimated Av>2.7Aj (accounting for J70 greater hull drag)
With equivalent sail forces, Viper accelerates nearly three times faster than J70.
Fun=f(A) (Acceleration is fun.)
Therefore, Funv>2.7Funj

Example: take a sharp puff in the Viper and accelerate from 6 to 12 knots in 3 seconds. J70 takes 10 seconds.

I love Viper sailors. Who can argue with math like that!?!

[Charlie Visser]

A Viper accelerating at 2 knots per second is equivalent to 0.1G
You can feel 0.1G acceleration but you probably can't feel 1/3 that much (J70) amid all the accelerative noise in a sailboat.
So in a Viper you can FEEL the acceleration. But, we already knew that from experimentation...

[Dan Tucker]

Someone needs to turn that mathematical reasoning into a t-shirt!

Fletcher? Fletcher? Anyone?

[Drew Harper]

Someone needs to turn that mathematical reasoning into a t-shirt!

Fletcher? Fletcher? Anyone?

I'm on it!

[Justin Scott]

The J70..............Chicks Dig It!

[Drew Harper]

The J70..............Chicks Dig It!

That's just SO wrong...LMAO

[Michelle Lee]

They're both very nice, for different reasons.  Full disclosure - my team and I are still fairly new to sailing and we're all women, so we probably look at some of the aspects differently.  I'm good friends with the local J boat dealer so was able to take out and race one of the first J70s last June.

J/70 - Very nice fit and finish.  Although people are making fun of the winches, they were great for my 100 pound crew member and would also be helpful for kids on the boat.  Felt very stable to sail, but slow (that could have been operator error, though).  Since I was familiar with using the backstay to depower, I found the backstay to be helpful.  When we sailed it in June, we weren't aware of any rules on leg out/in hiking, so we were legs out and even though we're pretty light, found it very manageable.  Although the initial cost is greater, resale is also usually good on Js.

Viper - The boat just looks better.  Gorgeous lines and looks fast.  We think once we get familiar with it, we can still sail it reasonably even though we're way underweight (360 pounds total for team).  Very manageable to tow and hoist, can even be pushed over to the hoist if needed.  Felt very similar to the dinghies we're more familiar with.  Would love to have a little more storage area for beer, food and clothes.

We decided to go with the Viper mainly because the class appears to be more friendly and fun.  Even among our local sailors who are choosing between the J70 and Viper, the ones who we'd most want to sail with are choosing the Viper and it's shaping up to be a great local fleet.  Every Viper sailor we've met and talked to has been the kind of person we'd want to sail with or against and then have a beer later to talk about it.  We can't wait to have our boat delivered and start sailing.

I'm posting not because I have any great expertise to share, but to give a look at what the everyday sailors might think.  You're not going to convince any of the experts through a forum, they have enough knowledge to choose for themselves.  But if you're going to grow a large class, you'll need some everyday sailors as well, so it's good to know what appeals to them and how they choose, too. 

[Peter Beardsley]

I actually did Key West in a J/70 this year on short notice and have been staying quiet on various Viper vs. J/70 threads.  Long story short: they're both solid boats, but there are some major differences.  I am pretty happy with my Viper and am not jumping to buy a 70, but I would sail one again if a friend asked, but not if it conflicted with a major Viper regatta. 

I'm not going to get into a big trash talking battle or elaborate comparison between the two boats.  What I would like to see is when you hear someone say something negative about a Viper, at least make sure it is from someone who has actually sailed the boat before.  There's a lot of misinformation on both sides, and our job is to at least give people the basis for making an informed decision to the extent they're interested in both boats -- take 'em sailing, let them see for themselves what the Viper and the people who sail them are all about. 

[Jeff Jones]

See yawl, that panda ain't so vicious

[Justin Scott]

Michelle,

I think that is the intention of this thread on the privacy of our own forum, to compare notes and avoid uninformed trash talking.

The Viper is ABOVE ALL, about making performance sailing accesible to the everyday sailor.  Sailing faster, lighter boats doesnt have to be harder or more technically demanding or ridicously expensive. A fast fun boat should be available to everyone.

But....historically, the first movers into fast boats were the high end technical sailors. As a result, sport boats and high performance dinghies required technical skills.  It doesnt have to be that way, nor do they have to be scary. They just have to be fast and fun......and we wanted to add the "easy" bit.

We also wanted to add the "affordable" part for the every day sailor.

There are lots of great things about the J70.
One difference between the Viper and the J70 is that the J70 allows you to hire professional crew. Well over 50% of the J70s at Key West were paying their crew. It is not only the expense at a going rate between $500-$1,000 per diem + expenses, but it is the atmosphere. One fleet (Vipers) is friends vs friends. At the other there are owners and employees at the regatta, and it jest feels different. People talk different, hang at the bar different.

You are very light at 360 lbs. Some of the more experienced Viperers can show you how to take power out of the rig and trade it for point.....but come 15-18 knots and Miami, you are going to be wanting to trade for weight....and the advantage of an all-girl crew is the terms of trade are all in your favor!   

Have fun, go fast......and see you out there soon.

[Paul Zinger]

I would add:

Force=Mass*Acceleration   F=MA
Assume Fv=Fj (assume Viper and J70 sail plans generate equivalent forward thrust)
Mv=750 lb
Mj=1750 lb
So, Mv=0.43Mj
Acceleration Av=2.3Aj
Estimated Av>2.7Aj (accounting for J70 greater hull drag)
With equivalent sail forces, Viper accelerates nearly three times faster than J70.
Fun=f(A) (Acceleration is fun.)
Therefore, Funv>2.7Funj

Example: take a sharp puff in the Viper and accelerate from 6 to 12 knots in 3 seconds. J70 takes 10 seconds.

I love Viper sailors. Who can argue with math like that!?!

2.7 with no crew on either boat?   No crew weight was factored in for the Mv or the Mj.

[Paul Zinger]

Mv = 1298 assuming 550# Crew Weight
Mj = 2425 assuming 675# Crew Weight

Mv=0.53Mj  Before anyone calls me out on it I didn't factor in the J/70s requirement to carry an outboard.

Assume a 3.5HP 2 stroke @ 30# if you want.

Don't worry the Viper is still more fun :) and less painful from what I hear.  So maybe that will balance it out.

[Charlie Visser]

Nice catch, Paul. But I was comparing crewless runaway boats ;-)
I modified my numbers above, fairly close to yours.
Point is, you can feel acceleration in a Viper; in a J70 not so much.