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

[Thalasso]

That picture is of reverse chines.Makes for a smoother and dryer ride along with better steering response
The flatter the hull the the less it rolls l-r in rough water while setting still but doesn't ride as well as a deep v. Deeper the v more l-r rolling while setting still in rough water.

 

[Grandad]

OK. This puzzles me. Like a lot of stuff does. What is reversed here? I know the term is legitimate, but what shape is a chine that's not "reversed"? - Grandad

 

[jbcurt00]

Look very closely at the graphic Thalasso posted. The reverse chine is lower at the far right edge compared to the left side where it intersects the rest of the hull.

Much more obvious on this graphic:

 

[ondarvr]

There are many vague and made up terms for hull designs, you can basically start calling something anything you want in advertising and get away with it, some terms stick and others don't.

A chine is just where the hull side and hull bottom meet, with a sharp chine you know exactly where it is, on a rounded chine it's a general area.

A reverse chine just angles back down before it meets the hull side, the exact size and angle is up to the builder.

 

[211libwtfo]

I have had the Starcraft that had this exact hull design 1968er. I boat on the upper Mississippi it would handle 5' waves no problem great on plane and cornering one of the best aluminum boats I've ever had. Not sure what it's called.

 

[Grandad]

Thanks jb. The hull pictured in your post definitely is "reversed" and that explains a lot. I see in Thalasso's post that it also is reversed but to a much lesser extent. And yes ondarvr, the advertising dept can sure get away with a lot, twisting words to promote a product. - Grandad

 

[Texasmark]

The "Chine" is the area between the hull and the side of the boat. The old Alumacraft, aircraft grade, 14' open skiffs, (Forget the numbers) were as good an example of a "rounded" chine I can think of, which just rolls from the hull up in an arc and becomes the side. Not very stable at rest, but being 5052 or a 6000 series tempered aluminum, it didn't lend itself to sharp bends without damage to the material.

Then there are hard chines, like the "Old Woodie" Chris Craft classics used back in the 30's and the (fiberglass) Ski-Nautique used years ago....maybe still do. The hull was reasonably flat going out to the chine, then a sharp turn upwards to within 80-90 degrees forming the side. Fit between the former and latter on performance. Using wood planking it made boatbuilding easier.

The reverse chine as shown, where the angle rather than sloping up towards the side "reverses" and angles down prior to becoming the side of the boat for the reasons mentioned was another method of interfacing bottom to side. Very good when used with a deep V for smooth, dry, ride.

Course the Tri-hull (OMC and Chrysler to name a couple) which incorporated a gull wing aka reverse chine but it continued on out and made a sponson was the most stable at rest, but wettest and hardest riding. The (Caravelle 18' Tri-hull to name one) deep V with sponsons solved a lot of those hard riding problems and were much dryer including the Tri-hedral hull that exaggerated the V and minimized the sponsons, the best of both worlds.........19' Trisonic, or FG Thompson for a couple.