What Class Boat Is This???

[Bill Roberts]

I'll be back.

[Kevin Keller]

I don't know.

[Mac M]

Judging by the file name, I'll guess hobie 16! I'll also guess that the thinner end is the bow. The flat side I'm assuming is what is used for lateral resistance to make it go upwind?

[Bill Roberts]

My problem is the file, the drawing, won't download to the forum. Matt says the file from my scanner is a . dat file and the forum will not take that.
Anyone know a solution. I was planning on drawing many sketches and then discussing them. It loks like that doesn't work with my scanner.
Bill

[T Peterson]

The drawings show up as .pdf files now and are easy to view

I recall the flat outboard sides from the Hobie 14 / 16 series and also the Prindle 16s had flat outboard sides. What they told us at the time was that the flat side helped reduced side slippage and that the curved inside produced lift to windward. Not sure if that was / is actually true.

Normally, I'd say the fat end is the stern, but the Hobie 16 is squared off at the stern and the hull shape in the water would not normally end as a point. But, due to the hull shape, the water footprint (is that even a proper phrase?) is greatly influenced by where the weight on the boat is placed. Most casual Hobie skippers sit way too far back because it's easy, it keeps the bows out of the water..., it rakes the rig back, etc. We learned racing these boats that moving weight forward would help in pointing and reduce drag. If you were on a Hobie 16 and had the bow deck just inches off the water, then I think your in-the-water hull footprint might be as shown. Or maybe if you put an empty Hobie 16 in the water and let it find its balance point then your footprint might be as shown.

OK, let's see what's next.

[havliii]

Bill, the attached pdf's are downloading fine.

What do you mean by 'class'? classification? ie the type of ship or hull form? my guess is asymmetric non-planning catamaran. the asymmetric 'planning' catamaran hull form would show chines in the immersed drawing.

[Bill Roberts]

Well, you can see something I cannot see. I do not see the sketch I made and scanned and tried to attach to my subject on this forum.
The drawing I made was from measurements on a hull shape at the LWL, load water line.
If you can see the drawing, there is something very wrong here. What is it???

I just tried to add the sketch again and I got a message back that said, "the extension is not allowed".

[havliii]

Bill, rescan your drawing, when using your scanner set the 'save as' selection box to 'jpeg.' you should have no trouble uploading a jpeg to the attachments section of this forum. The current attachment is in the 'pdf' format. Most scanners will allow saving as a jpeg.

[Bill Roberts]

The first question is what class of beach cat is this? Is it a Hobie, Prindle or NACRA?

Which end of the picture is the bow?

If the bow is where you said it was, something is really wrong with this boat design.

What is it ??????

[Bill Roberts]

Here is a half size copy of the picture, I hope.
My questions are the same.
There is one very glaring error in this hull design. What is it ???

[Kevin Keller]

As far as we know it's Hobie 16 without rudders. Skinny end is the front.

[jjd78]

I too think it's a hobie 14/16 but the skinny end is not the front.. the way i understand it these boat will only point when your flying the windward hull and just skimming it across the water and the stearn on a hobie 14/16 isn't this pointed as this is where the rudders attach.

[Bill Roberts]

It is a H16 and the skinney end is at the bow. The max hull width is at 2/3rds of the distance from the pointed end. The more blunt end is at the transom. What is wrong with this design??????????
Is this a proper foil design for generating side force at minimum drag all in the same body???????

[T Peterson]

Airplane wings, and sails, I guess, tend to have their thickest part maybe 1/3 back from the front. Fish have evolved this way, too. One of the best biographies I've read "One Good Run", the story of Bert Munro, aka "The World's Fastest Indian", told the story of how when he had to design a streamliner shell, he went to a local pond and sketched fish, one of the few times he did external research, being mostly self-taught. And fearless at speed.

So, speaking of self-taught, the Hobie 16 designers, Hobie Alter, and Phil Edwards, were surfers, and I'm not sure if they ever put much available science into their boat design.

It's really why we all have Supercats. I'll rent a Hobie, and have a fun day, if I am at a resort somewhere. I'll never own another one.

[Bill Roberts]

So Mr. Novice,
You are telling me that the H14 and H16 hull footprints in the water "are airfoils flying backwards"? The thin trailing edge is forward and the widest section is aft and the trailing edge/hull section is fuller than the leading leading edge? Now you are going to tell me that this is the most popular beach cat in the world? On top of this the boat pitchpoles easily and doesn't tack worth a darn. In summary these characteristics are what it takes to have very popular beach cat class. Is this correct???