Vee Angles

[Smelly]

Can someone please advise me what the angle is for :

Deep Vee
Semi-Vee
Shallow Vee


Thanks

[johnnytheone]

Smelly,
Mate, I don't know if there is any specific figure that separates one type of hull from another. From general chat with boat owners and reading adverts and so on, I suspect it's largely "in the eye of the beholder".
I don't know exactly what you're are after, but I would make a couple of a generalisations that :
1) The greater the "V" angle (Deadrise I believe is it's correct term), the heavier the hull needs to be to make it stable at rest, 'cause the hull needs to sit down to its chines to avoid flopping from side to side. I think this is why most tin hulls are fairly flat. (I believe there are a few more ali boat builders around now that are changing this, such as Noble Engineering)
2) The greater the deadrise, the better the ride, particularly in choppy conditions. A dive with clean, fine, entry generally hurts a lot less than a belly flop!
Like I say, they are generalisations, but I think fairly accurate.

Regards, John.

[Smelly]

Many thanks for your "V"ery detailed answer!

[Arlon]

I would call anything from above 21 deg a deep "V" 15-20deg a modified "V" and less than 15 a shallow V, less than 5 may as well be flat. Just my opinion and there are 100 people that will disagree with me I'm sure..

It's all a trade off. as far as stability, ride and economy go. Flatter it is the more stable and less HP it's going to take to run it. Deeper it is the smoother the ride and more power to run.

Personally I like the exrtreme variable deadrise like my panga has. My boat has a very sharp entry of 52 deg. #that really slices into a wave then flattens out 37 deg at mid ship and finally 20deg at the transom. This gives a very good ride of a "deep" V and maintaining some of the stability of the modified V. The important part is where the hull hits the water at the speed you cruise at. My boat cruises 45 kph and usually has at least half the boat in the water (that 37 deg point). I loose little or no ride quality with the flatter stern. If I had a much faster boat that rode further back on the hull, a steeper angle would definately help the ride. Also as the angle steepens, the boat has to get longer or narrower. Can't have a wide deep V. It will float on the V and be relatively unstable.

I'd love to get a ride in one of the hooker long boats with a 22deg (deep v) at the transom. Those boats are narrow enough they should remain quite stable and have a heck of a good ride for their size. That's pure speculation just from looking at a few pictures of the boats since I have not ridden on one.

Don't buy anything without getting a ride on a windy rough day. Some of the ugliest boats I've seen rode well and where very dry while the prettiest ones (on a trailer) pounded your brains out and gave a free shower to boot.

DEEP V entry
http://fototime.com/A65EE35BC7965AE/standard.jpg

MODIFIED V exit
http://fototime.com/3EC21B59CC078A4/standard.jpg

[Smelly]

Many thanks Arlon.

I ask boat dealers what the deadrise angle is on aluminum boats and they cannot tell me because they do not know..

The manufacturer I am pursuing is Ally Craft who are not answering their phones..

So, I am a bit stuck on the Ally Craft 4.5m Tank model..

[88fishframe]

Smelly, when buying a boat don't get too bogged down on the specs. Take it for a ride and make sure you get the chance to test it in the conditions you expect to encounter on your fishing trips. Apart from the vee, there are too many other factors which will come into effect like weight ect.. so each boat will differ slightly from each manufacturer. David 8-)

p.s. I like the Ally Craft Tanks.

[Smelly]

Thanks Fishframe - it is fun putting all the pieces together to establish an optimal match for what you want to do.. ::)

I am going to commit to the Tank with a new 50 HP 2 stroke Yamie..

Arlon, I am curious how the actual vee angle is measured?

i.e. If a vee if 22 degrees - where is it measured from?

If I stand at the back of the boat and bend down, how woudl I measure that angle of 22 degrees?

Smelly

[Arlon]

Make a crude divider with a couple of kids rulers (kind that fit in a binder already have 3 holes). Get the biggest protractor you can find in the school supply part of the store. I used a thumb nut, washers and bolt through the middle hole to make my dividers. Just use the divider on the hull to copy the angle, measure on the protractor. Subtract the measured angle form 180 and divide that by half and you have the number you are looking for.

Here is a picture worth 1000 words. Sorry for the quickie art work.
http://fototime.com/A107B6282C9ABA3/orig.jpg

[Smelly]

Excellent Art Work.

I am sure this lesson in Deadrise will be of interest to many others on this Forum as well.

Just out of curiosity, what approx. deadrise angles would you think are used in Racing Yachts in America's Cup Challenges?

Smelly!