InsTanton hard chine

[Ron Cook]

All this talk about Ragtime got me thinking about hard chine concept so I thought I would try my hand at it. Y_M_T you can have a good laugh at my expense. loa 65' lwl 56' beam 12' disp. 25,000# lcb 52% Cp .52

[Chris Ostlind]

Not laughing, Ron. She's a sweet shape.

I am, however, concerned about the spec numbers as posted.

The Cp looks to be on the thin side if you are going for speed. Perhaps you could give us some additional material as to the design goals?

Stepping up is always a good thing. Nice

[Ron Cook]

Chris It is nice to hear that you like the basic design. Thanks for saying so. The Cp at rest is .523 heeled 15 degrees it is .543 I know that is low for multihulls but but not to bad for a monohull. I kept the design narrow forward to lesson any pounding.

[Chris Ostlind]

There's still quite a bit to know about your overall design, Ron, before much input can be given. What are you doing about the sail plan, appendages, deck structure, cockpit placement and layout... all kinds of stuff.

I do think that the hull is pretty, but there is a need to balance the various attributes so that the boat is in harmony. Having slender forms forward can minimize pounding, but it may come at the expense of reduced buoyancy which has its own issues that aren't so much fun.

Since I'm not seeing a more cruising oriented design here, I'd guess that you are going for a fast craft. Even heeled, I have a feeling that you are going to exeprience a hull that might just run out of gas by having a low Cp like this. In light airs, this could produce an efficiently driven hull, but to easily reach higher boat speeds and then keep it there, I think you'll need to give the bow some help.

A Cp of .56 would suggest a decently all around form that can live in both low speed and higher speed activities.

Just some stuff to consider and you may have a completely different plan in mind. I'm looking forward to how you progress with the design.

[Ad Hoc]

Ron Cook

"...thinking about hard chine concept.."

Ok, you've posted a dwg of a hard chine lines. So, the question is, what is the concept for? It needs context to ascertain if it has merit or not.

That is to say, is this design for a canoe, or is it for a racing monohull Class III power boat or is it for a frigate??....it needs context to answer. As it is, it is just a nice shape.

[Ron Cook]

The hull is for sailboat that should be good in light to moderate conditions going to weather inshore or offshore. The sail area is 1,500 sq. ft. on a mast head rig. The SA/Disp. ratio is 28.3. It will need to be reefed early. The lifting keel is a deep narrow fin with a bulb of 8,000#s at the end. The boat has twin rudders. Pictured is the same hull with a Cp of .56

[Tanton]

Originally Posted by Ron Cook

The hull is for sailboat that should be good in light to moderate conditions going to weather inshore or offshore. The sail area is 1,500 sq. ft. on a mast head rig. The SA/Disp. ratio is 28.3. It will need to be reefed early. The lifting keel is a deep narrow fin with a bulb of 8,000#s at the end. The boat has twin rudders. Pictured is the same hull with a Cp of .56

Interesting thread. Ah. Ah!
I would prefer more deadrise, but as is, the concept is valid.
Next week, I 'll up-load an InsTanton 65' Tour Boat. An extension of SightSailer. Of course the goal for this sailboat differs from yours, but the hull shape will give a good idea about what an InsTanton hull shape is all about.
www.sightsailing.com

[Ron Cook]

Here is the same hull with more deadrise. The disp. has gone from 25,000# to 30,000# And the Cp has gone from .52 to .543

[Ron Cook]

Just for fun.

[billys maverick]

Greetings. Something about the phrase 'InsTanton' has caught my eye. Is this a trade name, geometry, or some defining feature?

[Tanton]

Originally Posted by billys maverick

Greetings. Something about the phrase 'InsTanton' has caught my eye. Is this a trade name, geometry, or some defining feature?

What is an InsTanton hull shape? Well. The deadrise is constant troughout, so that the bottom and the topsides planking (or plating, or glassing etc.) is bent in one plane only and not twisted. The chine does not create disturbance and with a slight angle of heel, the immersed lee chine cuts cleanly, while the raised one squelches the wave train and keep the boat dry.

[Tanton]

Designed for Vision Sailing, Ohio. A Tour boat. Up to 49 passengers.
Loa. 65' x Lwl. 60'-10" x Beam 12'-6" X Draft. lifting keel x Displacement 25,000Lbs. light. PC. 54.
Work in progress.

[Ron Cook]

More fun.

[Ron Cook]

A 97.5' VERSION Beam 16' DRAFT 16' Disp 48,000#

[Ron Cook]

Here are the lines to the above 97.5'er. LOA 97.5' LWL 88.5' LCB 54.6% aft
Cp .544 Note smooth the LWL aft is (top View). Tanton is brilliant!