Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 13-03-2013, 13:34   #1
Registered User

Join Date: Mar 2011
Posts: 88
Displacement???

I'm puzzled about what "displacement" of a sailboat means. Is it the weight of the boat with mast, rigging, sails, fuel, water, etc. or does it exclude any or all of those items. Perhaps there is an industry standard as to what boat builders mean when they give this figure but I haven't been able to find it.
__________________

__________________
nial is offline   Reply With Quote
Old 13-03-2013, 13:40   #2
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
Re: Displacement???

I can only say that it is usually the weight of the amount of water it displaces when it is unloaded. It usually does include mast, rigging, minimal sails and engine but doesn't normally include water, fuel electronics and food.

That's just my interpretation and I'm certain others will chime in and maybe we'll get someone who is a designer or in the boat business to help you with this question.

kind regards,
__________________

__________________
John
SkiprJohn is offline   Reply With Quote
Old 13-03-2013, 13:49   #3
Registered User

Join Date: Jul 2006
Posts: 3,949
Re: Displacement???

Boats displace a certain amount of water when they are afloat. If you could weigh every drop of water displaced when your boat is afloat, it would equal the weight of the boat. So, displacement is essentially the weight of your entire boat, and it goes up when you fill it with fuel, water, etc.
__________________
Kettlewell Cruising
Kettlewell is offline   Reply With Quote
Old 13-03-2013, 14:25   #4
cruiser

Join Date: Mar 2013
Posts: 59
Re: Displacement???

This is primary schools stuff...
Displacement is the actual weight of a vessel and everything onboard at the time of measurement
Light displacement - is empty vessel. The displacement will change with any additional weight. IE. if you add 100m of heavy chain the boat will displace more water. But the displacement will always equal the overall weight.

As previously said Archimedes Law - A body immersed in water appears to suffer loss of weight equal to its own weight
__________________
transformer is offline   Reply With Quote
Old 13-03-2013, 14:31   #5
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 4,586
Re: Displacement???

Displacement is sometimes spec'd as half-weight displacement. This means the displacement of the vessel with rig (weight of the water displaced) when the fuel and water tanks are half full.
__________________
Paul L
http://svjeorgia.blogspot.com
Paul L is online now   Reply With Quote
Old 13-03-2013, 14:38   #6
Freelance Delivery Skipper..
 
boatman61's Avatar

Community Sponsor
Cruisers Forum Supporter

Join Date: Jan 2010
Location: PORTUGAL
Posts: 20,224
Images: 2
pirate Re: Displacement???

Lets keep this simple.. ferget the crap 'sailors' are gonna come out with...
When you've filled yer bath... draw a line... when your in and settled... draw another line... the gap is how much water your body displaced.. same with boats..
Hope that cuts down on the armchair Googler's..
Get enuf boats they'll call it Global Warming
__________________


Born To Be Wild
boatman61 is online now   Reply With Quote
Old 13-03-2013, 14:47   #7
cruiser

Join Date: Mar 2013
Posts: 59
Re: Displacement???

Quote:
Originally Posted by boatman61 View Post
Lets keep this simple.. ferget the crap 'sailors' are gonna come out with...
When you've filled yer bath... draw a line... when your in and settled... draw another line... the gap is how much water your body displaced.. same with boats..
Hope that cuts down on the armchair Googler's..
Get enuf boats they'll call it Global Warming

...and you just invented the wheel. those previous posts were talking about agriculture.
__________________
transformer is offline   Reply With Quote
Old 13-03-2013, 14:59   #8
Freelance Delivery Skipper..
 
boatman61's Avatar

Community Sponsor
Cruisers Forum Supporter

Join Date: Jan 2010
Location: PORTUGAL
Posts: 20,224
Images: 2
pirate Re: Displacement???

Quote:
Originally Posted by transformer View Post
...and you just invented the wheel. those previous posts were talking about agriculture.
Cheers mate... 2 outa 3 aint bad...
__________________


Born To Be Wild
boatman61 is online now   Reply With Quote
Old 13-03-2013, 15:30   #9
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
Re: Displacement???

So, with all the answers we've come up with maybe we should as the poster what answer he really wanted. Light displacement, displacement or volume? Maybe he was looking at an ad for a boat and it gave displacement and he wanted to know if that meant loaded or light displacement.
__________________
John
SkiprJohn is offline   Reply With Quote
Old 13-03-2013, 15:41   #10
Registered User

Join Date: Oct 2012
Location: Melbourne Florida
Boat: Columbia 24
Posts: 98
Displacement = weight
Period
__________________
Eumelia is offline   Reply With Quote
Old 13-03-2013, 15:46   #11
Freelance Delivery Skipper..
 
boatman61's Avatar

Community Sponsor
Cruisers Forum Supporter

Join Date: Jan 2010
Location: PORTUGAL
Posts: 20,224
Images: 2
pirate Re: Displacement???

Quote:
Originally Posted by transformer View Post
...and you just invented the wheel. those previous posts were talking about agriculture.
PS... I'm a Newbie and try to keep things within my limited inteligence level... sorry if I caused offense... just trying to help..
Tell me when to stop grovelling
__________________


Born To Be Wild
boatman61 is online now   Reply With Quote
Old 13-03-2013, 17:08   #12
Registered User

Join Date: Dec 2007
Location: Duluth,Minnesota
Boat: Lindenberg 26 & Aloha 8.2
Posts: 984
Re: Displacement???

When you design a boat it is typical to include tanks half full, the volume is calculated at the load waterline, LWL or designed waterline,DWL, (which are both the same thing) which is just a line drawn on the drawing but it is an important one as this is this is where all those numbers that sailors are so keen on looking up online are generated from, when you start adding all the crap everyone carries these days that waterline dissapears underwater and those numbers become meaningless. It is unfortunate that there is not an industry standard for publishing displacement, many marketting departments will publish the lightship displacement because it makes the boat look faster.

Steve.
__________________
clockwork orange is offline   Reply With Quote
Old 13-03-2013, 18:03   #13
Registered User
 
sabray's Avatar

Join Date: Aug 2008
Location: Wash DC
Boat: PETERSON 44
Posts: 3,169
It's not weight it's displacement that confuses me. If I am in a tub of salt water do I displace less then I did when I was in fresh water. If yes then most women might be prefer to have a saltwater displacement then a true weight.
Never mind no women is going to tell you her displacement ever.
__________________
sabray is offline   Reply With Quote
Old 13-03-2013, 19:38   #14
Moderator Emeritus
 
Coops's Avatar

Cruisers Forum Supporter

Join Date: Jan 2012
Location: Northern NSW.Australia
Boat: Sunmaid 20, John Welsford Navigator
Posts: 9,550
Re: Displacement???

She would probably tell you that her "displacement" is being with you. She would much rather be elsewhere.

Coops.
__________________
When somebody told me that I was delusional, I almost fell off of my unicorn.
Coops is offline   Reply With Quote
Old 13-03-2013, 19:44   #15
Registered User
 
sabray's Avatar

Join Date: Aug 2008
Location: Wash DC
Boat: PETERSON 44
Posts: 3,169
I think you just broke the be nice rule. Even if your right it still breaks the rule.
__________________

__________________
sabray is offline   Reply With Quote
Reply

Tags
displacement

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:09.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.