A question about boat weight and displacement
 

On 1 Apr 2004 14:14:21 -0000, Ante Topic Mimara
] wrote:

DUINK writes:

As far as I know displacement = weight.

Somehow, this doesn't sound right to me.

Certainly the weight of the boat will displace the amount of
water with that same weight (hence the term displacement).

If something displaces X pounds of water, it must weigh X - n to
be able to float. It must weigh less than the amount of water it
displaces, else it will have neutral (or worse, negative) buoyancy.

This is Archimedes principle

"a body immersed in a fluid is buoyed up by a force equal to the
weight of the displaced fluid."

http://www.infoplease.com/ce6/sci/A0804583.html

Having said this, how do I determine how much it weighs, from
limited information, without being there to weigh it?

Displacement equals weight.

Jack

__________________________________________________
Jack Dale
Swiftsure Sailing Academy
Director
ISPA and CYA Instructor
http://www.swiftsuresailing.com
Phone: 1 (877) 470-SAIL (toll free)
__________________________________________________

A question about boat weight and displacement
 

On 1 Apr 2004 14:14:21 -0000, Ante Topic Mimara
] wrote:

DUINK writes:

As far as I know displacement = weight.

Somehow, this doesn't sound right to me.

Certainly the weight of the boat will displace the amount of
water with that same weight (hence the term displacement).

If something displaces X pounds of water, it must weigh X - n to
be able to float. It must weigh less than the amount of water it
displaces, else it will have neutral (or worse, negative) buoyancy.

This is Archimedes principle

"a body immersed in a fluid is buoyed up by a force equal to the
weight of the displaced fluid."

http://www.infoplease.com/ce6/sci/A0804583.html

Having said this, how do I determine how much it weighs, from
limited information, without being there to weigh it?

Displacement equals weight.

Jack

__________________________________________________
Jack Dale
Swiftsure Sailing Academy
Director
ISPA and CYA Instructor
http://www.swiftsuresailing.com
Phone: 1 (877) 470-SAIL (toll free)
__________________________________________________

A question about boat weight and displacement
 

"Doug Dotson" wrote ...
Just give the DOT a call. They can tell you the bottom line instantly.
10'6" is definately wide for towing, but I don't think it is wider than
a standard tractor-trailer.


legal width (standard trailer) = 8' 6''
anything more than that, you need permits.

SV

A question about boat weight and displacement
 

"Doug Dotson" wrote ...
Just give the DOT a call. They can tell you the bottom line instantly.
10'6" is definately wide for towing, but I don't think it is wider than
a standard tractor-trailer.


legal width (standard trailer) = 8' 6''
anything more than that, you need permits.

SV

A question about boat weight and displacement
 

No. Each state has it's own , sometimes unique, rules (laws).

What state(s) are you asking about?

SV

"Ante Topic Mimara" ] wrote in message
news:ALSJDPK238078.3918865741@anonymous...
Doug Dotson writes:

Just give the DOT a call.

DOT? This is Federal Department of Transportation, and not for
a single State, I presume?

They can tell you the bottom line instantly.

Fantastic idea! Thank you!

10'6" is definately wide for towing, but I don't think it is
wider than a standard tractor-trailer.

Truthfully, this width thing never occurred to me.

None of this has anything to do with weight and displacement
though.

Yes, it doesn't. Can you add anything to address this question?
Thank you so much for your other information.
---
-
Topic-Mimara
Unique in the World!
---


-=-
This message was posted via two or more anonymous remailing services.

A question about boat weight and displacement
 

No. Each state has it's own , sometimes unique, rules (laws).

What state(s) are you asking about?

SV

"Ante Topic Mimara" ] wrote in message
news:ALSJDPK238078.3918865741@anonymous...
Doug Dotson writes:

Just give the DOT a call.

DOT? This is Federal Department of Transportation, and not for
a single State, I presume?

They can tell you the bottom line instantly.

Fantastic idea! Thank you!

10'6" is definately wide for towing, but I don't think it is
wider than a standard tractor-trailer.

Truthfully, this width thing never occurred to me.

None of this has anything to do with weight and displacement
though.

Yes, it doesn't. Can you add anything to address this question?
Thank you so much for your other information.
---
-
Topic-Mimara
Unique in the World!
---


-=-
This message was posted via two or more anonymous remailing services.

A question about boat weight and displacement
 

As far as I know displacement = weight.


Ante Topic Mimara said:
Somehow, this doesn't sound right to me.

Dave wrote:
It is.

Sorry to disagree yet again, but it's not that simple. It depends very
much on whose figures for displacemnt you are using, and their intent.

The designers figure for displacement will be the boat's intended
immersed volume, converted to units of weight since water density is
relatively consistent. This will include the boat & all it's parts... it
usually but not always includes full water & fuel tanks, crew, and some
amount of supplies. In other words, the boats actual weight when in use.

The builders figure for displacement can be the same as the designers,
or it could be the actual weight of the boat as built, plus a
guesstimate of how much "stuff" it can reasonably be loaded with for
sailing... or it could be a fantasy intended to create a false
impression of good performance on potential buyers. Lots of times
builders start changing the design and end up with a boat that is
substnatially heavier than the designer intended.

Sometimes a "half-load" displacement is quoted, meaning what the boat
would weigh in the middle of a cruise.

In any event, since the post is intending to trailer the boat and needs
an accurate number for that purpose, it would be a really good idea to
simply weigh the thing. The displacement figure would be a good starting
guess, but it won't put Humpty Dumpty back together again if it turns
out to be wrong by a lot.

FB
Doug King

A question about boat weight and displacement
 

As far as I know displacement = weight.


Ante Topic Mimara said:
Somehow, this doesn't sound right to me.

Dave wrote:
It is.

Sorry to disagree yet again, but it's not that simple. It depends very
much on whose figures for displacemnt you are using, and their intent.

The designers figure for displacement will be the boat's intended
immersed volume, converted to units of weight since water density is
relatively consistent. This will include the boat & all it's parts... it
usually but not always includes full water & fuel tanks, crew, and some
amount of supplies. In other words, the boats actual weight when in use.

The builders figure for displacement can be the same as the designers,
or it could be the actual weight of the boat as built, plus a
guesstimate of how much "stuff" it can reasonably be loaded with for
sailing... or it could be a fantasy intended to create a false
impression of good performance on potential buyers. Lots of times
builders start changing the design and end up with a boat that is
substnatially heavier than the designer intended.

Sometimes a "half-load" displacement is quoted, meaning what the boat
would weigh in the middle of a cruise.

In any event, since the post is intending to trailer the boat and needs
an accurate number for that purpose, it would be a really good idea to
simply weigh the thing. The displacement figure would be a good starting
guess, but it won't put Humpty Dumpty back together again if it turns
out to be wrong by a lot.

FB
Doug King

A question about boat weight and displacement
 

Having said this, how do I determine how much it weighs, from
limited information, without being there to weigh it?

You can't. The dimensions (alone) of the boat don't dictate the weight. It's a
wooden hull......ok, how thick? Low deadrise or deep V? 1000 pounds of gear
aboard, or not? Way too many variables.

Figure that with the trailer it will be at least as heavy as the "displacement"
number plus the curb weight of the empty trailer. At least.

A question about boat weight and displacement
 

Having said this, how do I determine how much it weighs, from
limited information, without being there to weigh it?

You can't. The dimensions (alone) of the boat don't dictate the weight. It's a
wooden hull......ok, how thick? Low deadrise or deep V? 1000 pounds of gear
aboard, or not? Way too many variables.

Figure that with the trailer it will be at least as heavy as the "displacement"
number plus the curb weight of the empty trailer. At least.