May 8, 2012

Comparing boats

IF YOU'RE AS FASCINATED as I am by the way different boats behave, even when they look very similar, you should pay a visit to Carl's Sail Calculator.  Carl has listed the statistics of hundreds of different sailboats of all types and set them up on a website for easy access.  There, thanks to the magic of computers, you can study the characteristics of two sail boats side by side. You might even find out why that raggedy-looking little bucket always manages to come sailing past you in light weather.

You'll even be able to find out how comfortable your boat is at sea, compared with other similar boats, because Carl has built in a motion comfort factor, like the one designer Ted Brewer invented for fun years ago.  And, more importantly, you can compare capsize factors (boats with factors under 2.0 are considered safer and less likely to capsize at sea).        

The theoretical speed of each boat is listed, of course, but as it's a formula based on waterline length it can't possibly tell the whole story of how fast a boat will go in differing conditions of wind and sea. Nevertheless, when you compare one boat with another, it gives you a good idea of which is likely to get back home before the pub closes, and which will be stuck out in the bay after dark with a crew complaining that they're dying of thirst.

If you'd like to visit Carl's Sail Calculator, go to http://www.image-ination.com/sailcalc.html

Scroll down to Part 1 and click on one boat in each column, then click on "make a chart" just underneath.

There's lots more information on that site and I leave you to figure it out. Play nicely. Have fun.

Today's Thought
Science is wonderfully equipped to answer the question "How?" but it gets terribly confused when you ask the question "Why?"
— Erwin Chargaff, professor of Biological Chemistry, Columbia University.

Tailpiece
Police in Detroit arrested two kids yesterday. One was drinking battery acid, and the other was swallowing fireworks. They charged one and let the other one off.

(Drop by every Monday, Wednesday, Friday for a new Mainly about Boats column.)

5 comments:

Twillick said...

John,

I've visited Carl's site many times and really enjoy comparing the boat I have with many other designs in her category. I sail a Hughes Northstar 600(26'), a Sparkman and Stephens design. Have you heard of this boat? What is your opinion of her seaworthiness and performance abilities for coastal cruising. I live in Newfoundland, a tremendous place to explore in a sailboat. I love you site.

John Vigor said...

Twillick, I've no personal experience of the Northstar 26, but she certainly has a pedigree design. S&S have long had a reputation for fast, seaworthy boats, and this one, with its fin-and-skeg underbody, appears to to have been designed to the old International Offshore Rule. She's beamy for her length, which might make her squirrely on a heavy-weather run, but she will make a fast coastal cruiser with the admirable ability to get to windward in a hurry.

Cheers,

John V.

Twillick said...

John,

I agree with your points on the hull's performance manners. I'm usually behind my sailing friends as they are in larger boats, but never so far to miss supper. The boat's high freeboard and tumblehome took a bit of getting used to, but now I never notice it.
I've researched the IOR a good bit to get a better understanding of the boat's hull design and I think I was getting more confused by the minute.

Phil Carlson said...

I sail a Northstar 26 in the Gulf out of Tampa Bay. Very forgiving boat in heavy weather. Got stuck one night too far out failing to appreciate the forecast and spent the night and most of the next day in seas up to 4m. Scary as hell due to my inexperience, but the boat carried us through beautifully.

I've had her up to 6 kts under sail. Love the boat.

Phil

Phil Carlson said...

I sail a Northstar 26 in the Gulf around Tampa. Great boat. hull speed is a little over 6 kts. Very forgiving when the heavy stuff hits. She'll lay down to 45 if you don't get the sails in ahead of a Tampa Bay squall but pops right back up. Had her in 4m seas too. Very forgiving.