Discussions on everything about the J/30 Sailboat!
With your one stop source
The J/30 Marketplace
Join or Renew
Class Membership
J/Fest New England
Aug 10-11, 2019
Sail Newport

1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30 31
Today's Birthdays
No Birthdays
Newest Members
PatchofBlue, mikeinct, Skipper Kenny, amtdys, Joao Brito CHILE
870 Registered Users
Crew Manager Boat Websites

Boat Website subscriptions with
Crew Scheduling & Notifications

Created by former J/30 Rhapsody owner

West Marine Affiliate Link

West Marine - The worlds largest boating supply company!
J/30 Class Affiliate Program

J/30 Social Network
Popular Topics(Views)
762,814 Dacron Main
106,077 Ananda's Refit
Forum Statistics
Most Online165
Mar 24th, 2019
Previous Thread
Next Thread
Print Thread
Weight and waterline #18180
03/21/19 08:30 AM
03/21/19 08:30 AM
Joined: Jul 2018
Posts: 72
Burton, Michigan
nathankt79 Offline OP
Senior Member
nathankt79  Offline OP
Senior Member
Joined: Jul 2018
Posts: 72
Burton, Michigan
Does anyone have a handle on how much weight (on or off) will move the waterline on a J/30 a given distance...For instance, something like 300lbs=1"?



West Marine Affiliate Program

The J/30 Class Association has partnered with West Marine and is now a member of the West Marine affiliate program. You can support the J/30 Class when you make your West Marine purchases online. The J/30 Class Association receives a percentage of sales from your purchases when you click through from our website. Click the logo above and you will be directed to the West Marine website with a cookie that identifies you as a J/30 affiliate. You can also use any discounts that you may be authorized.
Re: Weight and waterline [Re: nathankt79] #18183
03/23/19 06:17 PM
03/23/19 06:17 PM
Joined: Sep 2000
Posts: 365
Rockwood, MI, USA
Russ Atkinson Offline
Senior Member
Russ Atkinson  Offline
Senior Member
Joined: Sep 2000
Posts: 365
Rockwood, MI, USA
How good is your math? I don't think there is a simple straight line ratio for pounds to inches since the hull gets wider and longer as it sits deeper in the water. That said lets do some simple math. 1 cubic foot of water weighs 62.43 pound. At the water line the boat is about 25' long and 8 ft wide. Figure the area of an eclipse that is 25' X 8' wide. Multiply it by 1/12' (1"). You will then have a rough idea of cubic feet of 1" of water at the water line
If your boat is out of the water - measure how much longer and wider it is 1" higher than the water line, 2" higher than the water line,etc.
Multiply each of those calc by the wight of 1cubic ft of water. It won't be exact but it will get you in the ball park.

Re: Weight and waterline [Re: nathankt79] #18188
03/25/19 11:16 AM
03/25/19 11:16 AM
Joined: Jul 2018
Posts: 72
Burton, Michigan
nathankt79 Offline OP
Senior Member
nathankt79  Offline OP
Senior Member
Joined: Jul 2018
Posts: 72
Burton, Michigan
Thanks for the input. I can probably riddle that out. I was really hoping someone already figured out a chart or something, lol. I'm trying to figure out how much the weight savings of switching to lithium batteries would have on freeboard. I also read something that said if one can reduce weight forward and aft of the center 1/3 of the hull, she'll cut through waves a bit better without "slapping".

Moderated by  David Erwin 

Who's Online Now
0 registered members (), 13 guests, and 1 spider.
Key: Admin, Global Mod, Mod
Endeavour (246) Sailing in Prince Edward Island
First cruise
Fotos Regatas 2017 Tomine Colombia
Regata Armada Tomine Colombia Julio 2017
Recent Posts
Lost the Main Halyard
by --Ajax--. 05/17/19 09:31 PM
J30 Spinnaker for Sale
by ReneB. 05/17/19 03:46 PM
Electrolysis on Prop (Significant)
by Russ Atkinson. 05/16/19 05:56 PM
Fuel Filter Coming Loose
by Rhapsody #348. 05/15/19 06:28 AM
Throttle assembly
by Jeff B. 05/14/19 11:45 AM
Halyard Locations
by Rob Van Name. 05/08/19 02:32 PM
Class legal #3 Carbon Blade
by JPM. 05/06/19 10:39 AM
Brand New Lewmar 40 Self Tailing 2 Speed
by Jim_Hilton. 05/05/19 02:42 PM
J30 complete set of newer interior cushions
by lumpy. 05/04/19 09:12 PM
What's Inside the Boom
by Rhapsody #348. 05/04/19 12:25 PM
Powered by UBB.threads™ PHP Forum Software