Hi again Catalina Savants,
So, I wanted to start another thread about used sails in general, and how to measure/calculate sizes for our boats, as I'm a little confused as to what I've seen online.
I do plan to actually measure my boat, but from the owners manual, for both Mk I and Mk II, the dimensions of the boat are:
I: 44.75 (Basically, the distance from the top of the mast to the deck)
J: 14.33 (Distance from foresail tack at the bow to the base of the mast. This is the foot of the foresail triangle.)
P: 39 (Height from boom to top of mast, not needed for foresail calculations.)
E: 12 (Length of boom, not needed for foresail calculations)
Okay, so what I'm trying to do is look at used sails, to figure out a.) if they'll fit my boat and b.) if so, what size or percentage of the foretriangle that sail would be.
For example, I'm looking at a Catalina 34 OEM headsail that measures 44.5 luff, 41.8 leech and 19.2 foot with an LP of 18.2 with a #6 luff tape.
One way I've seen of determining percentage of the foretriangle is to simply divide the foot measurement of the sail by J. In this case, that would be 133%, which is a little big for what I'm looking for.
But if I divide LP by J, another calculation I've seen, it comes to 127%, which is close enough to the 125% that I'm after.
So, here are my questions:
1. Which is the right way to calculate this?
2. I assume if I get a shorter luff than the 44.75 "I" of our boats, it will fit. Is this a valid assumption?
3. If either of these is the correct way to determine percentage of the foretriangle, then do luff and leech length not figure into the overall size calculation in terms of percentage? It seems like you could have a sail that is technically rated as a 125% based on J or LP, but with a big variance in actual square footage, depending on the length of the leech. Is this correct?
Finally, the sail I'm looking at says it has never been used and is brand new. It is priced at right around $1,000. That's about $3000 less than the quote I got from my sailmaker to make a new one for my boat.
The possibility of that considerable discount is why I'm investigating this. If anyone has experience buying used sails -- I've discovered a number of outlets online, I listed them in my previous post about South East Asia Sails -- I'd love to hear about how it went.
Thanks in advance,
Joe
SV SYLBO
1994 Mk 1.5, hull 1337, M35AC
San Francisco Bay
Joe Bousquin, San Francisco Bay
Sausalito Yacht Harbor
SV "Sylbo"
1994 Catalina 36 Mk 1.5, hull number 1337
M35A(C)
This can be simplified to just comparing the area of triangles, so you just need the formula of base*height/2. 100% is I*J/2. For a genoa with the clew close to the deck you could calculate the area as I*foot/2. For a higher clew you need to use L*LP/2 because the mast is not perpendicular to the foot. Then just divide the area of the sail by the area of the forward triangle for percentage size.
Regarding the luff length, I is the length of the mast from the deck not the length of the forestay. The estimated luff length is 47' according to this: https://sailboatdata.com/sailboat/catalina-36/?units=imperial, but you need to also know how much space the roller furling hardware takes up to determine the max luff.
Eric Howell
Take Five
Seattle, WA
1989 MKI Tall Rig #1013
C36/375 IA Webmaster
Thanks, Eric. It seems like the way the sailmakers do it is to divide LP by J to determine overlap. For instance an LP of 17.91 on our boats divided by 14.33 = 1.249, or 125%
Also, here's an interesting tool I came across, a sail overlap calculator: https://sailingfortuitous.com/jib-calc/#:~:text=It%20uses%20Heron's%20Formula%20to,make%20it%20a%20tidy%20percent.
Noted on I vs. max luff, thanks for pointing that out.
I plan to haul a 165 ft tape I bought at harbor freight up on my spare jib halyard this weekend, pull it tight and then measure to the tack attachment point on the top of the Schaefer furler. Then I will probably subtract about a foot to make sure I don't buy anything too big. (I will also attach a painter to make sure I can get the halyard back down!)
I also found another good article on the pros and cons of buying used here: https://www.godownsize.com/things-to-know-buying-used-sails/ They make some very good points.
And, just to put everything in one place in case someone else reads this thread and wants to look at buying options, here are all the sites I've found:
http://www.minneysyachtsurplus.com/sails.html
https://www.secondwindsails.com/
https://www.usedsails.com/
https://baconsails.com/bacon/select_sailboat_API.php
https://www.sailexchange.com.au/collections/mainsails?pf_t_luff_length_r...
https://mastheadsailinggear.com/used-sails/
https://sailtrader.com/used-sails/
https://sailbritemidwest.com/collections/used-sails
Masthead Sailing is particularly interesting. I talked to the owner, and he said he bought all of Catalina's old sail inventory from the California factory a few years back. So he has new Catalina OEM sails that haven't been used. I'm looking at what was a 135 on the Catalina 34 that would be about a 125 on our boats. Price is around $1200 with shipping for a brand new sail.
All in all I've been finding a lot of options for used out there, and at much more affordable prices. I'll report back if I end up buying something.
Joe Bousquin, San Francisco Bay
Sausalito Yacht Harbor
SV "Sylbo"
1994 Catalina 36 Mk 1.5, hull number 1337
M35A(C)
Not sure what they have but our local consignment chandlery has a used sail selection.
mikescms.com
David Lane
S/V Grace
88' Catalina 36'
Oxnard, Ca
Thanks, David, I hadn't seen that one. Looks like another good resource to add to the list.
Joe Bousquin, San Francisco Bay
Sausalito Yacht Harbor
SV "Sylbo"
1994 Catalina 36 Mk 1.5, hull number 1337
M35A(C)