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What is chine?

8K views 17 replies 9 participants last post by  deniseO30 
#1 ·
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! :confused:
 
#2 ·
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
 
#3 · (Edited)
#4 · (Edited)
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.:)

 
#6 ·
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..:)
 
#9 ·
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?
 
#7 ·
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.
 
#8 · (Edited)
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
 
#14 · (Edited)
w1651...I'm guessing that those folk elsewhere were talking about a separate keel rather than is seen on the Tahiti where the keel being full length is integral to the hull. More modern designs have fins keels that are (or at least appear to be) an add-on to the hull.

Here's a pic of a full keel, the second is a full keel with a cutway forefoot. The third is the next step on the evolutionary path being a largish fin with a skeg hung rudder. The idea being to reduce friction underwater and to improve hydrodynamic efficiency. BobMcG's second pic shows the end result with a very radical fin. From their we move to canting.







The question as to which underwater shape is preferable for a cruising boat is one best left for another day. Once the simple question like the Origin of the Universe have been sorted we'll get back to you. :)

This last pic is of Silver Raven (aka the Womboat) herself when she was up having her bottom cleaned. She is a Van de Stadt 34. The hull being built from steel using multi chines. In old girls like Raven this was done to save time and money.



Yoiks...I lied.....that was not a skeg hung rudder at all....this is a skeg hung rudder....



btw....Bob Perry has written a series of very good articles for Good Old Boat on the subject of keels. If you can find copies you'll learn much from reading them. (that one of BP's design above..the Valiant 40, as is my third pic being a Perry 45.)
 
#17 ·
I have been informed in not so subtle a way that Breach is what happens to Pregnant women at times. i just want to say I stand corrected, Though I have seen a few boats in this condition.
I meant to say reach (A wind coming straight at the beam of a boat either port or Starboard) :laugher With a 35% heel and the rail in the water.
 
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