Simple Nomenclature Question

[frank pedersen]

Suppose you had a lines drawing of a boat with a relatively wide keel plank and four lapstrake planks. That would mean there are three chines, which could be identified as 1, 2, and 3. My question is what would you call the corner defined by the keel plank and the garboard plank? In a traditional boat there is the rabbet line, but that does not seem right when the garboard plank overlaps the keel plank. Or is it another chine? In Steward's "Boatbuilding Manual," he says "a rabbet line is usually found in traditional wooden construction . . . in other hulls a similar line may be referred by some other name. In any case the lines plan will make all of this clear."

Well, yes, but is there a word for it?

[Peerie Maa]

I believe that that is always the chine.
If the topsides are conventionally built lapstrake, the laps will not be as prominent as on a multichine plywood boat, and are just referred to as laps.
Properly speaking and borrowing from big boat parlance the topside "chines" on a multi chine boat should be called knuckles.

[Hwyl]

I'll chime in with chine too.

[Ian McColgin]

Keel plank? Do you mean something like dory construction with a narrow flat bottom? Or like a skiff with a shallow V or even flat bottom both more likely to have a more discernable keel as such, a center bottom member?

In general terminology the chine is NOT dependent on a corner between planks. There's soft and round chine boats, after all. The chine is really that transition from the bottom to the topsides. Boats with very slack bilges have no readily discernable bilge as the change in slope from the very steep deadrise of the bottom to the more nearly verticle topsides is ever so slight.

Boats with flat or nearly flat bottoms, even bottoms well below the waterline as some Bolger bricks and even bottoms very very narrow like dories have the chine where the sides attach to the bottom. Boats that have a real keel, a fore and aft structural member to which the garboard (lowest plank, not including any planks in a built-down keel) attaches will have the chine up nearer the waterline, above or below or above at the ends and below amidships.

There are some boats that are designed or redesigned to have multiple chines, two not infrequent and three quite rare. Not uncommon in steel, these are narrower bands to spread the angular change from bottom to topsides out a bit. It's still a discernable change. The gentler changes from plank row to plank row in the bottom or in the topsides are not chines.

[Thorne]

My first reaction was correct -- ain't no such thing as a "Simple Nomenclature Question". As I've mentioned before, nautical words & terms have no hard & fast meanings unless they are defined (and usually enforced) by some bureaucratic entity or government. Otherwise they are usually vague guidelines at best...

This catmaran hull designer refers to ridges / bands on the sides as "knuckles" - http://www.sailingcatamarans.com/hullshapes.htm

Wikipedia agrees with Ian, see the section on multichines -
http://en.wikipedia.org/wiki/Chine_%28boating%29

I'll admit that I always thought of the chine as something on a non-lapstrake hull. Some of the planks (or combinations thereof) in some locations on the lapestrake hull (usually the middle) may create what would be considered "chines", others may only create a ridge or offset the thickness of the plank.

For example, the top two strakes of my dory skiff create an almost-chine, while the rest just the usual lap.

http://www.luckhardt.com/nrow4.jpg

[frank pedersen]

Thanks guys,

You prompted me to do more homework. To have a better idea of the kind of boat I am trying to describe, think of a Shellback (three planks rather than the four in my description.) Looking at Eric Dow's "How to build" manual, I notice he refers to the bottom as the "bottom panel." In my thinking that was a "keel plank" much like a dory. Having sailed a Wayfarer for many years, I have always thought of its design as a "double chine." I noticed that the transition points on the Shellback are referred to as the "laps" and there is no mention of chines. Also I think of a Shellback as having a lapstrake planking system even if the planks are rather wide.

My goal is to identify the transition points in a lines drawing from which offsets are calculated, so I think I will go with "lap" in spite of my earlier attraction to "chine."

[donald branscom]

Keel plank? Do you mean something like dory construction with a narrow flat bottom? Or like a skiff with a shallow V or even flat bottom both more likely to have a more discernable keel as such, a center bottom member?

In general terminology the chine is NOT dependent on a corner between planks. There's soft and round chine boats, after all. The chine is really that transition from the bottom to the topsides. Boats with very slack bilges have no readily discernable bilge as the change in slope from the very steep deadrise of the bottom to the more nearly verticle topsides is ever so slight.

Boats with flat or nearly flat bottoms, even bottoms well below the waterline as some Bolger bricks and even bottoms very very narrow like dories have the chine where the sides attach to the bottom. Boats that have a real keel, a fore and aft structural member to which the garboard (lowest plank, not including any planks in a built-down keel) attaches will have the chine up nearer the waterline, above or below or above at the ends and below amidships.

There are some boats that are designed or redesigned to have multiple chines, two not infrequent and three quite rare. Not uncommon in steel, these are narrower bands to spread the angular change from bottom to topsides out a bit. It's still a discernable change. The gentler changes from plank row to plank row in the bottom or in the topsides are not chines.

Good points. I did see a steel boat built with overlapping strips(planks) once.
All 4 inch strips the length of the hull clinker style !