what is the conversion for - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > General Interest > General Discussion (sailing related)
 Not a Member? 


Reply
 
LinkBack Thread Tools
  #1  
Old 02-05-2008
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,696
Thanks: 0
Thanked 21 Times in 20 Posts
Rep Power: 10
blt2ski will become famous soon enough
what is the conversion for

figuring out disp from lbs to cubic feet. I was trying to figure out the SA/disp for my boat, but need this conversion.

Thanks
Marty
__________________
She drives me boat,
I drives me dinghy!
Reply With Quote Share with Facebook
  #2  
Old 02-05-2008
Owner, Green Bay Packers
 
Join Date: Sep 2006
Location: SW Michigan
Posts: 10,318
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 12
sailaway21 is just really nice sailaway21 is just really nice sailaway21 is just really nice sailaway21 is just really nice
64 lbs/cuft of SW, 62.35lbs/cuft of FW

or
2240lbs(1 ton)=35.84 cu ft FW
2240ibs(1 ton)=35 cu ft of SW
__________________
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.

Last edited by sailaway21; 02-05-2008 at 10:31 PM.
Reply With Quote Share with Facebook
  #3  
Old 02-05-2008
Senior Member
 
Join Date: Aug 2006
Location: Arlington, VA
Posts: 1,810
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 10
btrayfors will become famous soon enough btrayfors will become famous soon enough
One cubic foot of seawater weighs 64 pounds.
Reply With Quote Share with Facebook
  #4  
Old 02-05-2008
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,696
Thanks: 0
Thanked 21 Times in 20 Posts
Rep Power: 10
blt2ski will become famous soon enough
Thanks, that is what I needed.

marty
__________________
She drives me boat,
I drives me dinghy!
Reply With Quote Share with Facebook
  #5  
Old 02-05-2008
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,696
Thanks: 0
Thanked 21 Times in 20 Posts
Rep Power: 10
blt2ski will become famous soon enough
arrrrg,

so what am I doing wrong?

formula sa/disp

Sail area in sq ft divided [by disp in cu ft times 2/3]

so
626/13448lbs or 626/[13448/64]2/3

626/[210 x 2/3] = 4.47-1?!?!?!?!?!?! Should be closer to 18 or 20-1!

Where did I screw up?
__________________
She drives me boat,
I drives me dinghy!
Reply With Quote Share with Facebook
  #6  
Old 02-06-2008
Member
 
Join Date: Apr 2006
Location: Georgian Bay
Posts: 61
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 9
Rodz47 is on a distinguished road
hmmm ..... blt2ski ... are you sure that your formula is right?? I would rather use the following:
626 / [(13448/64) ^2/3]
where "^" means power. Your result would be closer to the number you expected ... 17.71.
Have fun,

Chris
Reply With Quote Share with Facebook
  #7  
Old 02-06-2008
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,696
Thanks: 0
Thanked 21 Times in 20 Posts
Rep Power: 10
blt2ski will become famous soon enough
I knew I was screwing up somewhere! Did not know how and why and where!

Thanks Chris!
__________________
She drives me boat,
I drives me dinghy!
Reply With Quote Share with Facebook
  #8  
Old 02-06-2008
chucklesR's Avatar
Senior Member
 
Join Date: Sep 2007
Location: Pasadena Md - Magothy side
Posts: 5,978
Thanks: 10
Thanked 30 Times in 30 Posts
Rep Power: 10
chucklesR is a jewel in the rough chucklesR is a jewel in the rough chucklesR is a jewel in the rough
a nice link for this http://www.nwmarinedesign.com/sadscrip.htm

Probably too late but make sure you are using SA as measured with a 100% foretriangle - that is the standard and the only way you can compare to other boats. Also use your real displacement for real numbers, not the factory delivered weight (unless you are just comparing fantasy numbers).

Using the actual SA - say with a 150% genoa might give you and warm and smug feeling, but then you can't compare with other boats.

Note some manufactures/sales people will cheat the numbers to make their boats look better.
As an example my boat (Gemini 105mc)
with 100% foretriangle only has 590 sq ft- 20.5 sa/d
with 150% (670 sq ft) - 23.3 sa/d
with screacher (780 sq ft) - 27.1 sa/d

I'm pretty sure all the sq ft measurements on mine include the roach on the main, so as you can see, it's apples and crab apples.
Reply With Quote Share with Facebook
  #9  
Old 02-06-2008
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,696
Thanks: 0
Thanked 21 Times in 20 Posts
Rep Power: 10
blt2ski will become famous soon enough
Chuck,

I know about those fun ways to fool around the numbers, the sq ft I mentioned, is with a 100 jib, no roach main etc, granted factory disp number, as I do not have actual disp number.......I was seeing one that was 23or24-1 for the S/A, but figured that was with a 140'ish or 150'ish genoa. I've seen some rigs in the 60-1 with super huge spinnys...........

nice link, I had not figured there would be a site like this, but in reality, there should be with plug in the numbers and voila, out comes ratio.

Marty
__________________
She drives me boat,
I drives me dinghy!
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Conversion from In-Mast furling to Lazy-Jacks system possible? freeheel999 Gear & Maintenance 21 09-14-2009 10:17 AM
Head - electric conversion or new electric head snw Gear & Maintenance 5 04-29-2007 07:07 AM
Conversion coat for 2 part polyurethane? equitiman Gear & Maintenance 13 12-23-2006 04:32 PM
Cal 27 Pop Top Conversion DonaldAdams General Discussion (sailing related) 2 07-10-2006 11:24 PM
MD3B Volvo-Penta sea water to fresh water conversion slosharron Gear & Maintenance 20 06-17-2003 09:08 PM


All times are GMT -4. The time now is 09:01 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.