can anyone tell me what this hull shape is designed for?

[driscollies]

sorry for my ignorance in advance, I know basically nothing about hull design but I'm learning!

went to go check out a boat the other day that ended up being kinda junky but it had a hull I'm not familiar with. It was like a normal V hull but it had little "wings" on the sides. I was too stupid to take a photo but I found this picture on the internet:






it looks just like this hull right at the very stern. deep V, but with wings. And maybe the wings were a little bit bigger that these in the picture, but they weren't SO large as to be like a cathedral hull or anything.

An here's the other thing, the wings didn't go all the way to the bow. They started about halfway back and swept out until they were fully formed near the stern. I'm trying to find a picture on the internet of what i mean, but the bow was definitely pointed and shaped like a normal deep v monohull.


What are these hulls used for? Are they good on rough water? The image that I found on the internet (the one above) was called "comfort V hull" but I don't see any hull designed called a 'comfort v hull'.

Any insights from the experts? thank you

 

[driscollies]

Edit: looks like they're called Reverse Chines. Guess I answered my own question happy to hear what anyone thinks of them still, though

 

[G_Hipster]

Trophy 2352 has a similar designed hull. They call it sequential lift or some such.

 

[alldodge]

Looks like deep V with single chine. Here is one with multiple chine's

 

[Grandad]

No Title

Our 17' 1972 Winner Eliminator had a stepped vee hull. It moved pretty good pushed by an 80 HP. Riding on those steps seemed to give a lot of lift and displaced less water at speed. - Grandad

 

[mr 88]

They are there to create lift while running and stability while anchored/trolling/drifting.

 

[ondarvr]

Our 17' 1972 Winner Eliminator had a stepped vee hull. It moved pretty good pushed by an 80 HP. Riding on those steps seemed to give a lot of lift and displaced less water at speed. - Grandad

I don't see that being a stepped hull.

 

[jbcurt00]

I don't see that being a stepped hull.

I think he used the wrong term, I agree that Winner doesnt look like a stepped hull. I've heard the additional chines/strakes or the reverse angle hull called steps before, also in error.

Stepped hull:

 

[Texasmark]

They are there to create lift while running and stability while anchored/trolling/drifting.

And they deflect spray down which provides the lift, and being a hard, reverse chine bite hard making a solid turn, like a professional ski boat might use. I think Glastron is using that hull design these days, surely among others. The step to allow the water out (when finished with it) may exist, or the chines just blend into the hull for a smooth water exit. This is different from a tri-hull (too many to name back in the late '60's and '70's....I had an 18' Caravelle bow rider) which gull wings roll the water away from a monohull (rough riding and trip when quartering big waves, especially on the helm side) and not like a Trihedral with the exaggerated monohull and sponsons (Thomson, Mark Twain to name a couple).

 

[Ned L]

As Texasmark indicated, they also help knock the spray down, giving a drier ride.

 

[Grandad]

I think he used the wrong term, I agree that Winner doesnt look like a stepped hull. I've heard the additional chines/strakes or the reverse angle hull called steps before, also in error.

Right on , jb. Sorry, I did use the wrong term as evidenced by its application to hull planes that break athwartship. The Winner design has unusually wide "flats" (?) or chines (?) or strakes (?) running lengthwise seemingly similar to that described by the original poster. What is the correct term for this hull? - Grandad

 

[jbcurt00]

SC used those reverse chines and called it an inverted Vee, IIRC, but I think the SC guys here refer to it as a bat-wing hull......

Actual term escapes me, for Glastrons it was an Aqua-lift design for the reasons Tx Mark mentioned.

 

[Texasmark]

If we missed it here the steps incorporated into deep V hulls were called "lifting strakes" defined by my Apple imac dictionary: "A continuous line of planking or plates from the stem to the stern of a ship or boat". As the V cut through the water, and the water would rise up the sides of the V, placing these horizontal deflecting strakes along the V caused the water to divert horizontally forcing the V up and providing lift, besides helping to divert the water to the side and maintaining a dry ride, especially when the wind is off the "quarter" or "abeam" to toss in a couple of Nautical terms. Grin

In rough water they also slowed the penetration of the V into the chop also smoothing out the ride.....like a shock absorber. I guarantee you that the difference in my 1971 16' Chrysler Sport Fury, lightweight,Gull wing designed, tri-hull and my 1972 18' Caravelle, heavy, deep V tri-hull was night and day. Noticing the year models, one season of the Chrysler was obviously enough for me on getting bounced around.

 

[jbcurt00]

Yep ^^^ and gull wing is how the Starcraft guys refer to that style of hull. Not bat wing :facepalm:

 

[garbageguy]

Looks like the hull of our 2000 17 ft Starcraft (fiberglass) open bow, and 1998 Wellcraft 25 ft express cruiser. Both are pretty stable at rest and on plane, take chop very well.The 25 ft is good in mild swells. A true deep V may be better taking moderate

 

[jimmwaller]

Logistical question ? are these wings typically hollow, or how are they constructed? Seems like they could add to the weight of a boat a bit.
Also, are there different angles? I wonder if the angle of the reverse chine affects the ride

 

[driscollies]

thanks for the replies.

Guess these are not as good as a legit V hull but are still pretty good? I have a pretty flat runabout right now, was looking for something that will slam less because mine SLAMS

guess I'll keep this hull shape in mind but with the knowledge that a true deep v will be better with the slamming. or are these not THAT much worse in big chop? 2-3 feet?

 

[mr 88]

On a hull under 22 ft that design won't have any affect on you pounding, the boat isn't wide enough to not disperse water in a timely fashion. A deep V without them isn't going to ride any different in 3-4 footers. I would look for either hull design and if I was going to troll,fish,anchor,drift for any length of time the reverse chine would be my first choice to keep the rocking to a minimum. If I was just going to go out and burn gas at high speeds all day in rough water then a deep V without the chines would be my choice for that even though the difference would be minimal .

 

[driscollies]

oh cool thank you mr 88 that makes sense. but that brings up another question that I have, which is then will moving from a runabout to more of a deep v make a difference? My boat now is pretty pointed at the bow to slice through the water easier but it also is pretty flat on the bottom. like starting from about halfway back there's maybe 5 degrees of deadrise or maybe less. at the stern I am pretty sure there's no deadrise.

But it's only 17 feet long and the beam is probably 5 feet so maybe it also isn't wide enough to not disperse water in a timely fashion? and maybe the slamming is just gonna happen even with a deep v? Or is there a major difference in going from a flatter hull to a deeper vee hull? thank you again

 

[mr 88]

Yes there is a major difference going from a flat bottom to any variation of a "deep V" .more so as well if going from from aluminum to glass. The angle of the bow does help somewhat but its not going to completely break the wave down so you have a smooth ride in choppy waters.