Saildata Comfort Ratio: Nonsuch 26 vs Nonsuch 30

[Surendira Siva]

I am about to purchase my first sailboat, and yes, it is a Nonsuch, 1982 NS26.

I was also looking at a few NS30C and NS30U models. While I like them, I found NS26C quite adequate for my needs.

But any idea why the comfort ratio is higher for the 26 model, dips for 30? I haven't sailed on a 30, so asking the community for your feedback.

Thanks,

Siva Surendira
NS26 "Inner Peace"
Jersey City, NJ

[Mark Powers La Reina 26C Vancouver, B.C.]

Siva, I have used the Tom Dove calculator to come up with numbers and they differ from yours. The comfort ratio for the 26 and 30 are 22.94 and 22.55 respectively so the difference is smaller than you get. I think the extra beam is what gives the 30 the lower number. 

Not all of your chat shows up but what is there indicates you are getting different numbers for the 30 Classic and Ultra. As far as I can determine all of the critical weights and measurements  Are identical on the two models. Sail area 540 sq ft, LWW 28’ 9”, beam 11’ 10”, displacement 11,000 lbs. and ballast 4500 lbs. what numbers do you have and where did you obtain them?

What does “S#” represent?

I have done a spread sheet of  calculations for all of the fleet and some other boats that I found interesting however I have found a couple of errors in it that need correcting so have not attached it. 

Mark Powers

[Surendira Siva]

Thanks Mark.

I did the calculation at https://sailboatdata.com/compare/.

What is S#?

S# first appeared (that we know of) in TellTales, April 1988, “On a Scale of One to Ten” by A.P. Brooks . The equation incorporates SA/Disp (100% fore triangle) and Disp/length ratios to create a guide to probable boat performance vs. other boats of comparable size.   For boats of the same length, generally the higher the S#, the lower the PHRF.
Under 2 – Slow, under powered.
2-3 – Cruiser
3-5 – Racer Cruiser
5+ – Fast/Racing
S# = 3.972*(10^(-[@[Dsp/LWL]]/526+(0.691*(LOG([@[SA/Dp]])-1)^0.8)))

-Siva Surendira

NS26 "Inner Peace"
Jersey City, NJ

[Bob Neches (Me Gusta, Nonsuch 26U #233)]

I have trouble understanding the sailboatdata.com/compare results for several reasons.  

I don't find my N26 to be at all underpowered, as this S# calculation suggests. 

Furthermore, I think I recall the designer, Mark Ellis telling me that he gave the N26 more sail area for its size than the N30.  The N26 was designed three years after the N30 (1981 vs. 1978) and, in that time, he'd realized the boats carried their sails better than he'd first expected.

I don't know what goes into the particular comfort ratio calculation used.

FWIW, I myself don't think (and I believe I could track down a source quoting George Hinterhoeller saying the same thing specifically about the Nonsuches), that any factory-built boat actually comes in at its as-designed weight.  So, I suspect that 8500 lbs for N26s and 10,500 lbs for N30s are both a bit low.  That will have some minor effects on the calculations.

-- Bob

   Me Gusta

   Nonsuch e 26U #233

[Brian M. Godfrey]

   I suspect that the comfort ratio better reflects the real world when applied to more conventional boats: sloops, more conventional beam/length ratios, shorter&lighter masts for the length of boat, etc.  It's a touchy-feely kind of calculation - "comfort" is a subjective term - and so the more unusual the boat, the harder it is going to be to fit it into a formula.  Our boats are not totally crazy, but they certainly are unconventional. 

   What the C.R. attempts to quantify is how "jerky" or "snappy" the boat is.  I guess the theory is that a light, stiff boat is going to have an uncomfortable motion while a boat with softer motion will be more comfortable.  And while the various sizes of Nonsuch probably compute out differently from one-another, they have so much in common that I suspect the ride is going to be similar from one size to the next.  And those figures bear it out.  If an NS26 is 23 and an NS30 is 20, that's not really much of a difference.  Go compare them to a Nauticat 44 (C.R.=45) or a Formosa 51 (C.R.=55) - a couple of heavy, seagoing boats that come easily to mind.  I've sailed the Nauticat and yes, it probably is about twice as comfortable as my NS33.  (Along with being twice as expensive to buy and own, and requiring way more than twice the effort to sail.)

--Brian M. Godfrey
  Vela, NS33, San Diego
  br...@wildbirdshop.com

--
You received this message because you are subscribed to the Google Groups "INA Nonsuch Discussion Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to INA-Nonsuch-Discussi...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/INA-Nonsuch-Discussion-Group/e3b46964-1e07-4a71-b979-cb7ee26b74f3n%40googlegroups.com.

[Mark Powers La Reina 26C Vancouver, B.C.]

This what Ted Brewer said about the comfort ratio:

COMFORT RATIO (CR): This is a ratio that I dreamed up, tongue-in-cheek, as a measure of motion comfort but it has been widely accepted and, indeed, does provide a reasonable comparison between yachts of similar type. It is based on the fact that the faster the motion the more upsetting it is to the average person. Given a wave of X height, the speed of the upward motion depends on the displacement of the yacht and the amount of waterline area that is acted upon. Greater displacement, or lesser WL area, gives a slower motion and more comfort for any given sea state. 

Beam does enter into it as as wider beam increases stability, increases WL area, and generates a faster reaction. The formula takes into account the displacement, the WL area, and adds a beam factor. The intention is to provide a means to compare the motion comfort of vessels of similar type and size, not to compare that of a Lightning class sloop with that of a husky 50 foot ketch. 

The CR is : Displacement in pounds/ (.65 x (.7 LWL + .3 LOA) x B^1.333). Ratios will vary from 5.0 for a light daysailer to the high 60s for a super heavy vessel, such as a Colin Archer ketch. Moderate and successful ocean cruisers, such as the Valiant 40 and Whitby 42, will fall into the low-middle 30s range.

Do consider, though, that a sailing yacht heeled by a good breeze will have a much steadier motion than one bobbing up and down in light airs on left over swells from yesterday's blow; also that the typical summertime coastal cruiser will rarely encounter the wind and seas that an ocean going yacht will meet. Nor will one human stomach keep down what another stomach will handle with relish, or with mustard and pickles for that matter! It is all relative.

Notwithstanding Mr. brewer’s calculations I find I am more comfortable in 30 over the 26 when the waves start going above 2 feet.

According to the Tom Dove Calculator the 26 has the lowest sail area to displacement ratio of the fleet at 16.13. The 324 is best at about 18. Both the 26 and the 324 have the highest aspect ratio for the sail at 2:1. A higher aspect ratio is better in light air. The 26 also generally rides a bit higher at the stern. I think this also helps in light air.  The 30s drags their sterns a bit. The 26 seems a bit faster than the 30 in winds below 10 knots. From 10 to 14 knots if the seas are flat the 26 will hold its own but above that the 30 pulls away. The 30 also copes better with wave action. Of course sail condition, loading and skipper all make a difference. 

Mark Powers

[newelljc9]

One has to include the size of the crew when considering comfort. The Pangmans bought Mascouche because they were small. They found that they could brace themselves between the seats in the cockpit and always able to reach the grabrail around the cabin trunk or post down below in the Nonsuch 26C. The 30 was just too big for them without a major redesign of the cockpit. I am 6' tall and enjoy full headroom. The only compromise is the space around the steering wheel. 

John Newell

Mascouche 26C 1

Toronto

PS: The 30lb boom mounted 4' above the deck improves stability while reducing windage.

[Paul Miller]

Mathematics aside I suspect that anyone who gives the 26 a higher comfort ratio than the 30U is less than 6’4” (like me). Having sailed lots of boats I believe that the very worst headroom is “almost enough”. Sitting headroom is better.

Just sayin….

Paul M

NS30U #211, Sandpiper

Cowichan Bay B.C.

[Mark Powers La Reina 26C Vancouver, B.C.]

According to John, if you are short a 30 maybe too big and according to Paul, if you are tall a 26 maybe too small. Maybe we need a sizing guide for the fleet.

I am 5'8" tall. In the 26 when riding as a passenger, it is comfortable for me to sit side ways and brace myself with my feet against the seat on the opposite side of the cockpit. In the 30, I find I can't reach the far seat unless I slide away from the coaming.  I also find it interesting that on the 26 the side deck and the cockpit seats are at the same height but on the 30s the seat is lower than the side deck. It always catches me by surprise when I step into a 30 and my foot drops a couple of inches more than I anticipate. The height of the seat above the cockpit floor is also greater in the 26 than the 30 and the headroom over the quarter berths in the 26 is greater than in the 30 classic. I am not saying one is better than the other and it really comes down to what a person is used to. 

Mark Powers

[Ernie Abugov P/O NS22 o/b #56 "Moustaches"]

At a splendid 5'6.5" tall, I find the NS 22 to be the perfect size. No head-banging below. And, if you sit on your folded-cockpit cushions, you can actually see a bit over the cabin top. Otherwise, it's like Lindbergh in the Ryan aircraft "The Spirit of St. Louis" - NO front window. Or like a big old locomotive with those two tiny corner-style front windows forcing the engineer to stick his head out the side window (while eating LOTS of smoke and ash). Phoooooo ......

Sorry, I have digressed and hijacked this thread (a little). Happy New Year to y'all.

Ernie A. in Toronto (still no snow ..... )

[Surendira Siva]

Thanks. Just completed my 26C purchase. :)

--

You received this message because you are subscribed to the Google Groups "INA Nonsuch Discussion Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to INA-Nonsuch-Discussi...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/INA-Nonsuch-Discussion-Group/4f59c09c-0575-40e6-9610-021976b8692an%40googlegroups.com.

--

Regards,
Siva
+91-99021 91202

[Ernie Abugov P/O NS22 o/b #56 "Moustaches"]

Congrats !! It's a great boat.

Ernie A. in Toronto

[Thor (26C Brentwood Bay BC)]

In general terms

The 26 being lighter and having a higher aspect ratio does better in light air.  In heavy weather the 30 has more weight to punch with.

The 26 benefits from a 20 hp engine.

We find the 26 perfect for two, and we've had 2 grand kids on board for extended periods .

The 30 has much larger cockpit lazerette storage  so more room for stuff to look for and lose :)    but access to the mast is a PITA compared to the 26.

The choice apart from the these few minor items is  somewhat narrow are they both will perform in similar fashion.. 

[Bob Neches (Me Gusta, Nonsuch 26U #233)]

There are a few weeks a year when the seas get a bit higher and closer together and I think a heavier N30 would be nicer than my N26, and a few days a year when the wind conditions have been such that a N30 sailed faster and I was jealous.

The last time those factors really got to me, I went shopping for a N30 and sold my N26 in order to buy... another N26.   As I looked at N30s, I realized that I'd be buying more boat than I needed, at more expense than necessary, engendering more work for myself than I felt like doing, just to have it a little better a few days a year and a bit worse a few days a year.  I ended up switching from a Classic to an Ultra and an aluminum mast to carbon fiber, but staying the same size. 

The choice of boat is virtually impossible to make going just by the numbers.  It really depends on your local conditions, your age/height/weight/agility, your budget, and its match with your needs and interests.  

That said, as an engineer, I'm really curious about the story behind the numbers.  Based on my experience with the boats, I don't understand how a N26 got rated underpowered or how an N30 gets a lower comfort number than an N26.  My guess is that it says more than anything else about how numbers aren't always perfect at predicting people's subjective experience.  But, it'd be interesting to understand what factors produced the numbers.

-- Bob

   Me Gusta

   Nonsuch e26U #233

[Mark Powers La Reina 26C Vancouver, B.C.]

Here is a link to an explanation of the comfort ratio calculation and an excerpt from the article.

https://wavetrain.net/2011/10/15/crunching-numbers-brewer-comfort-ratio/#:~:text=To%20calculate%20Brewer%27s%20comfort%20ratio,length%20is%20expressed%20in%20feet.

To calculate Brewer’s comfort ratio, you need to run the following formula: Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam↑1.33), where displacement is expressed in pounds, and length is expressed in feet.

As an example, let’s again consider a hypothetical 12,000-pound boat with a load waterline length of 28 feet. Let’s assume it also has a length overall of 35 feet, and a beam of 11 feet. Therefore, to find its comfort factor, we first need to multiply its LWL by .7 (.7 x 28 = 19.6) and its LOA by .3 (.3 x 35 = 10.5) and should then add these two results together, which gives us 30.1 (19.6 + 10.5 = 30.1). Next take the boat’s beam to the 1.33 power, which gives us 24.27 (11↑1.33 = 24.27), and multiply this result and the previous result by .65, which gives us 474.84 (.65 x 30.1 x 24.27 = 474.84). Finally, divide this result into the boat’s displacement, which yields a comfort ratio of 25.27 (12,000 ÷ 474.84 = 25.27).

What the formula purports to assess is how quickly and abruptly a boat’s hull reacts to waves in a significant seaway, these being the elements of a boat’s motion most likely to cause seasickness. The formula favors heavier boats over lighter boats, as more weight always helps to dampen a boat’s motion, and also favors boats with smaller waterplanes. This refers to the horizontal plane on a boat’s waterline and is generally a function of length and beam. Boats that weigh less and have more waterplane tend to have a quicker motion, because more waterplane means there’s more area for waves to push up against and less weight means there’s less resistance to the pushing.

Longer boats obviously have larger waterplanes than shorter boats, but the exponential increase in their displacement always negates this. As a result, the comfort-ratio formula also favors length, though it penalizes beam. Generally, it favors heavy boats with overhangs and narrow beam, but longer boats may have considerably lower D/L ratios than shorter ones and still fare much better by comparison.

You can use the following guidelines to interpret comfort ratio results: numbers below 20 indicate a lightweight racing boat; 20 to 30 indicates a coastal cruiser; 30 to 40 indicates a moderate bluewater cruising boat; 50 to 60 indicates a heavy bluewater boat; and over 60 indicates an extremely heavy bluewater boat. If evaluating a larger boat, say 45 feet or longer, expect your results to be skewed a bit higher on this scale; if the boat is quite small, say 25 feet or less, they will be skewed slightly downwards.

Once again, increasing displacement to account for loads carried seriously affects results. Our hypothetical 12,000-pound boat, with its comfort ratio of 25.27, becomes decidedly more comfortable as we load it to cruise. Add on another 2,500 pounds for light coastal cruising, and the ratio rises to 30.5; make that an extra 3,750 pounds for bluewater cruising, and it becomes 33.16.

The 26 is listed at 8500 lbs displacement but at the annual bailout she usually tips the scales at 10,000. I suspect the 30s which are listed at 11,500 more often come in above 13,000. Filling the big water tanks and lockers quickly add on the pounds.

Mark Powers

[Ernie Abugov P/O NS22 o/b #56 "Moustaches"]

I believe that the calculation for comfort deals with the beam of the skipper, not the boat.

Ernie A. in Toronto