What is chine?

[w1651]

I know I am showing my newbie status but what is Chine. I was reading about a John Hanna Tahiti ketch with no keel or very little anyway. And the people on the forum were talking about rolling, chine and multi chine.
What the hack are they talking about? Thanks!

[deniseO30]

Like a corner.. boats like flat bottom boats where the bottom meets the side. it's a "hard chine"

Boats like a kayak that have semi vee bottoms the turns are chines. if they are rounded. they are soft chined.


CHINE (Chine log)
The junction of the side and bottom planking or the member backing this junction.
DOUBLE CHINE - Having an additional planking junction between the chine and the sheer, giving the hull a more rounded look.
HARD CHINE- Having a distinct bottom/side planking junction as opposed to a rounded curve.
MULTI-CHINE - Having one or more additional planking junctions between the chine and the sheer.

Glossary of Boat building Terms

[Faster]

Denise has nailed it.. here's some more info and pics

Google Image Result for http://content.answcdn.com/main/content/img/McGrawHill/boating/f0056-01.png

Many homebuilt, metal, and plywood designs are either single or multi "hard" chined designs - they are simpler to build, especially with flat panel materials like ply and metals.

[bobmcgov]

Very hard chines (YKY (Class 40) and Ragtime, respectively):





Very soft chines (12m yacht and the oh-so-tender Bucc18):





Hard chines (generally) provide good initial stability, improved tracking or leeway prevention by "biting" the water, and excellent power to windward. By carrying the planing surface of a racing boat to maximum beam, they can also improve planing performance downwind. But they also sometimes make a boat willful to steer, uncomfortable in a seaway, 'notchy' when heeling (always wanting to lean too far or slam back down flat), and hard chines may cause 'bumps' in a stability curve, sacrificing reserve buoyancy for initial stability.

I love the upwind power, downwind planing, and initial stability of the Lightning 19 (hard chines), but it can be a rascal in those intermediate, puffy winds when it can't decide whether to heel 35 degrees or stand upright. Notchy bugger.

[RobertKWFL]

A chine is a distinct edge where bottom and sides meet. Hardness and softness describe the angle of the edge. Contrary to common usage, a hull with a rounded curve (no edges) doesn't have a "soft chine"; it has no chine at all.

[w1651]

Thanks guys and Denise I appreciate the info. Now the next and obvious question is what about a keel and ballast. If you have a soft or no chine hull without any defined keel, stability goes out the window on a breach doesn't it, or does the width of the beam compensate? Still without any ballast I gotta think reefing is going to be a way of life on a breach.

Take a look at this

tahiti ketch Tahiti Ketch Steel bare hull&deck sailboat for sale in Massachusetts

This sailing thing is hard. My brain is starting to hurt..:-)

[danjarch]

Your going to have a keel or some other way of controlling the leeward slipage on any sail boat. The one your showing above is known as a deep vee hull and would have some kind of ballast planned to keep it low enough in the water for the vee hull to act as the keel. What your more likely discribing is a cat boat, and that would use a center board or a lee board to give it purchase as it cut through the water.

[deniseO30]

Chines don't make that big a difference to initial and secondary stability when used as they are in that steel hull. It's a bare hull. you have to add ballast. Your looking at $18,000 for that and about $130,000 to finish it! Then you will have fix all the rust that set in while you were building it.

TAHITI KETCH Sailboat details on sailboatdata.com





Steel Tahiti Ketch - Tahiti Rover Plans

TABLE OF COMPARISONS (back to top)
ROVER

*TAHITIANA

*HANNA
L.O.A. 31' 11" 31' 7" 30' 0"
L.W.L 28' 0" 27' 0" 26' 0"
BEAM 10' 2" 10' 2" 10' 0"
DRAFT 4' 2" 4' 2" 4' 0"
DISP. 18,411 lbs. 18,194 lbs. 18,100 lbs.
SAIL AREA 581 sq.ft. 550 sq.ft. 470 sq.ft.
DISP./SAIL 31.68 33.08 38.51
PRISMATIC .528 .562 .577
BALLAST 6200 5300

[knothead]

Originally Posted by w1651

Thanks guys and Denise I appreciate the info. Now the next and obvious question is what about a keel and ballast. If you have a soft or no chine hull without any defined keel, stability goes out the window on a breach doesn't it, or does the width of the beam compensate? Still without any ballast I gotta think reefing is going to be a way of life on a breach.

Take a look at this

tahiti ketch Tahiti Ketch Steel bare hull&deck sailboat for sale in Massachusetts

This sailing thing is hard. My brain is starting to hurt..:-)

What is a breach?

[w1651]

Originally Posted by knothead

What is a breach?

I know it as a wind coming directly from port or starboard. Not aft or forward.
Im new at this so bear with me.