boat brands - prejudice or reality

[potentillaCO32]

I was on a modern HR the other day. No chart table is not a feature I'd like on any boat irrespective of age or manufacturer.

Maybe charts are on their way out. Did it have a nav station for chartplotter/tablet etc

 

[Egret]

Another question - if we want a boat that is going to take a bit of rough and tumble, maybe a long way away from a repair yard, do we really want a foam or balsa sandwich hull, or would we rather have solid GRP

 

[Tranona]

Another question - if we want a boat that is going to take a bit of rough and tumble, maybe a long way away from a repair yard, do we really want a foam or balsa sandwich hull, or would we rather have solid GRP

What difference does it make? Why do you think a cored hull is any more of a problem than a solid one? The vast majority of modern boat have cored hulls and there does not seem to be an epidemic of problems with using them or getting them repaired if damaged.

If it makes you feel better have an old boat with a solid GRP hull or even a steel, ferro or wood. .

 

[Tranona]

As an engineer familiar with thermofluid having spent a chunk of my career working in that field, I can honestly say that's not correct.
You are correct that chines added above the waterline are useful for adding reserve buoyancy. My 32 year hard dinghy has such features. It does add reserve buoyancy but also plenty of drag when the chines are immersed. Anything that increases surface area as chines does increases drag, particularly in light winds.
Interestingly, more volume is achieved by a hemispeircal shapes with less surface area than any chine. A round bilge boat has less drag than a flat one with chines.

Well I would stack David Thomas and all the other designers who use chines successfully against you any day of the week. We are not talking about old dinghies but substantial cruising boats where the designers have worked out that carefully positioned chines at the stern improve performance, reduce drag and increase buoyancy and allow more hull volume.

 

[Tranona]

Are you sure they are not mentioned? The website says “The new hull design with wider transom and lifted soft chines suits the X4³ MkII very well. The additional form stability is quite noticeable, as is the considerably less wake and turbulence of the heeled transom travelling through the water.”
X4³ MkII |.

You are doing it again - quoting facts straight from the builder. If I could be bothered I could probably dig out Maurice Griffiths comments on the redesign of the GH31 with double soft chines which made exactly the same point over 50 years ago.

 

[Laminar Flow]

On chine hulls:
Chined hulls have a minimum 5% higher resistance than round bilge forms. This was established by tank testing. Rounding off the chine, R= 0.008 DWL, significantly improves resistance. (Konstruktion u. Bau von Yachten, Scharping, page 96 and continued)

Yes, I too have owned a Griffiths chined design. My current, round bilged tub would absolutely sail circles around it (see avatar).

The success of the early Van de Stadt hard chine designs had nothing to do the chine. It was because they were significantly lighter than the competition.

The well known IMOCA designer Juan Kouyoumdijan explains the advent of contemporary chine design:
"In order to reduce the extraordinary beam the wide arc of the bilge would dictate, we simply cut off the excess." There, bingo, you got your chine!
When asked about the adoption of it in contemporary AWB design, he laughed.

I'm sure I'll be accused again of ignoring empirical data by someone who took a walk through the marina counting boats with chines and, consequently, conclude they must contribute brilliantly to a boat's sailing ability and for the obvious reason that people bought these boats and that there is a market for ones that, at the least, look fast.
By the same measure, if a few years ago, counting the number of fins and rocket extrusions on cars in a parking lot would have led to the obvious conclusion that these accoutrements must greatly improve aero dynamics and allow automobiles to fly.