Discussion. Help me understand more in depth...clr! looks can be deceiving

[boatsail]

Ok. Here goes. Looking at the 2 boats in the attached photos. You will notice a fin keel on the Cal 40 and full keel on the Norsea.

That being said. Look at where the center of lateral resistance is located o the hull. More centered on the Cal and more toward the rear on the Norsea.


Wouldn't this make a full keel boat's bow "blow off" much more than a fin keel? I have heard plenty of stories of great pointing full keel boats, but I'm only really exp. on fin keel as a point of actual personal reference.

I would LOVE to sail both boats in similar conditions around a course to get a better understanding from personal exp, but will have to come here to ask instead.

Can the Norsea or another full keel boat point as high as the fin keel?

[Paul L]

The simple answer is no. A full keel may track better, i.e. stay in a straight line, better, but it won't point as high as foiled fin keel.

[Wrong]

"Look at where the center of lateral resistance is located o the hull. More centered on the Cal and more toward the rear on the Norsea."

Your objective criteria for making this statement please?

[Wrong]

Originally Posted by Paul L

The simple answer is no. A full keel may track better, i.e. stay in a straight line, better, but it won't point as high as foiled fin keel.

Pretty presumptive statement considering only two boats are under consideration. Don't you think it depends upon the boat design, weight distribution and sail plan? Some boats with 'foil fin keels' will sail like a pig...

[boatsail]

Originally Posted by Wrong

"Look at where the center of lateral resistance is located o the hull. More centered on the Cal and more toward the rear on the Norsea."

Your objective criteria for making this statement please?

That is the reason I was asking the question. I don't have a degree in engineering or physics. When I observe the two pictures I applied rationale.

If I were to draw a vertical line centered between the bow and stern of each boat, and pushed each "half" with equal force, what half would have less "friction" and therefore "give way" more. To me the answer is that the Norsea has less friction under the front half of the boat, so therefore would not be able to point as well due to the bow "blowing off" more than say the Cal I used in the example.

I don't know if I'm right or wrong, but figured that the knowledge base on here could probably give a more technical answer than mine and I could learn something from this thread and maybe others could too.

Plus, it was either this or start a gun thread.

[Teknav]

Sailing like a pig, may not necessarily be bad! Flying like a pig, is a whole new thread!

Mauritz
Going to behave someday!

[Wrong]

Originally Posted by Teknav

Sailing like a pig, may not necessarily be bad! Flying like a pig, is a whole new thread!

Mauritz
Going to behave someday!

See: 'Flying Hawian is Gone' for that discussion...

[Teknav]

As a general rule, the greater the keel's displacement the more stable the boat is and the slower as well.

Mauritz
Your opinion of me has no cash value!

[Wrong]

Originally Posted by boatsail

That is the reason I was asking the question. I don't have a degree in engineering or physics. When I observe the two pictures I applied rationale.

If I were to draw a vertical line centered between the bow and stern of each boat, and pushed each "half" with equal force, what half would have less "friction" and therefore "give way" more. To me the answer is that the Norsea has less friction under the front half of the boat, so therefore would not be able to point as well due to the bow "blowing off" more than say the Cal I used in the example.

I don't know if I'm right or wrong, but figured that the knowledge base on here could probably give a more technical answer than mine and I could learn something from this thread and maybe others could too.

Plus, it was either this or start a gun thread.

Your choice is politically correct..

Google 'center of effort ' related to sail boats for a primer.

I own a Nor'Sea27 and she can be made to point higher by running the jib sheet inside the shrouds. There is a lot more than just keel configuration that affects a boat's ability to point higher into the wind.

[Cheechako]

I'm not seeing the CLR noted on the drawings.? But the short answer is no, the fullish keel wont point as high as the fin. The difference can be dramatic. (on a lucky day, trying hard, the HC38 in the avatar at left would tack through 120+ degrees..... in a chop more like 160!) it probably had a better "bite" on the water than the Norsea 27... (deep draft)
Having said that.. you get used to what you have and plan accordingly. Gentlemen never sail to weather...

[Wrong]

Originally Posted by Teknav

As a general rule, the greater the keel's displacement the more stable the boat is and the slower as well.

Mauritz
Your opinion of me has no cash value!

I was tempted to give a retort, but since you said - "As a general rule..." I'll pass.

I'll take stability (safety) over speed any day.

[Wrong]

Originally Posted by Cheechako

I'm not seeing the CLR noted on the drawings.? But the short answer is no, the fullish keel wont point as high as the fin. The difference can be dramatic. (on a lucky day, trying hard, the HC38 in the avatar at left would tack through 120+ degrees..... in a chop more like 160!) it probably had a better "bite" on the water than the Norsea 27... (deep draft)
Having said that.. you get used to what you have and plan accordingly. Gentlemen never sail to weather...

Uh, oh. My competitive juices are starting to flow!

[Cheechako]

and........ whatever boat has the shorter waterline will be slower... regardless of keel. But the lighter one will accelerate faster to hull speed....

[monte]

the bow should't blow off on the full keel. The CLR is designed to balance the CE (center of effort) A quick glance at the rigs would indicate the CE on the full keel is further aft, hence the CLR is further aft (roachy main with boom to the transom) also the draft is less on the full keel. No reason it wouldn't point as high or as fast as the fin keel. If the CE and CLR aren't balanced you would have lee or weather helm and too far off balance would be unsailable. Adjust sails/reef to maintain balance. My guess is the full keel would track slightly better and turn slightly worse and be a b*tch to reverse.

[Wrong]

Originally Posted by Cheechako

and........ whatever boat has the shorter waterline will be slower... regardless of keel. But the lighter one will accelerate faster to hull speed....

And, the boat with the longer water line length will probably cost a lot more too! May not want to take the lighter boat cruising though, eh?

Since Cheechako brought CLR into the discussion, see this: What is “lead” in sailboat design. Joe self designs a rig and finds something interesting. | Storer Boat Plans in Wood and Plywood