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Old 04-10-2008, 13:31   #106
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Originally Posted by fastcat435 View Post
Hallo Freetime

the weight difference starts with the Naval Architect that projects a weight for any given Yacht and the builder that uses different techniques , materials , more equipment and as a result comes up with a (more often than not ) heavier yacht than predicted.
Than as the yacht is build in series weights keeps on being added since often upgrades are added , A bigger anchor winch , more chain, bigger winches added portholes more sails etc etc.
Just an example on the ( I know you do not like the word ) FastCat All 5 winches are now of a larger size than originally intended and one is now standard electric.
10 meters anchor chain and 50 meters weighted line was standard but now it is 25 and 50 meters standard , 8 portholes where standard now there are 12 , a list like this is endless and the total weight difference can be huge.

Greetings

Gideon
So now you have me curious. If you dont know for sure how much the boat weighs then how do you know where to paint the boot stripe? Or is the boot stripe painted after you have pulled the ready to sail boat back out of the water?

With commercial vessels the naval architect knows exactly where a ship is going to sit in the water according to where its cargo, fuel, water etc is located. Small boats dont have these tables? And whats real nice, is you can run these tables in reverse and determine the displacement of the vessel according to how much water the vessel draws at the bow and stern. (accounting as well for hogging and sagging with a ship..but insignificant for a boat)

I'm sort of surprised naval architects of small boats dont create these tables. They certainly have the computers and the software to determine displacement volume at specific drafts. This whole heated argument about determining a boats weight could have been eliminated with these tables simply by observing its draft at the bow and stern.

So, why are these tables not created to take the guesswork out of determining the displacement (weight) of a vessel?
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Old 04-10-2008, 13:50   #107
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Hitch-hike, with a sign that says "Divorced; How was Yours?" Five cars won't pass before you have a ride!

[guaranteed thread hijacker]
Thanks, i will start to build the sign tonight.

I work in her company also... Another sign?
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Old 04-10-2008, 14:55   #108
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I work in her company also... Another sign?
Yeah that's a good sign for you to get that Cat you've been dreaming of and disappear!
No time to waste!!!
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Old 05-10-2008, 06:34   #109
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Originally Posted by David M View Post
So now you have me curious. If you dont know for sure how much the boat weighs then how do you know where to paint the boot stripe? Or is the boot stripe painted after you have pulled the ready to sail boat back out of the water?

With commercial vessels the naval architect knows exactly where a ship is going to sit in the water according to where its cargo, fuel, water etc is located. Small boats dont have these tables? And whats real nice, is you can run these tables in reverse and determine the displacement of the vessel according to how much water the vessel draws at the bow and stern. (accounting as well for hogging and sagging with a ship..but insignificant for a boat)

I'm sort of surprised naval architects of small boats dont create these tables. They certainly have the computers and the software to determine displacement volume at specific drafts. This whole heated argument about determining a boats weight could have been eliminated with these tables simply by observing its draft at the bow and stern.

So, why are these tables not created to take the guesswork out of determining the displacement (weight) of a vessel?

The proffessional NAs do a comprehensive weight study during the design process. This is used to ensure the correct trim, displacement etc. under a given set or sets of conditions.The draught/displacement tables are easy to make with the software that is used these days, but they are seldom published. What you sometimes will see published are the immersion rates in mms/ton or pounds/inch. But this is often only for a certain start displacement as the hulls are seldom vertical on the sides.

The problem is when the builders, don't build as specified, and the basic boat is heavier than it should be. This happens with both infused, vacuum-bagged and hand lay-up.

The next area of weight gain is probably the biggest problem to manage, all the things that go into the boat, be it deck hardware, machinery, wood trim, safety gear, batteries, chargers, whatever.

If the builder or the owner does this in an uncontrolled manner, the end result as is often seen, is a boat that is far over the originally designed weight.

Few builders document this during build, as it is not in their interests, nor do they get paid to do it. When the owner finds out the boat is way too heavy, they can never find out exactly why, so they learn to live with the fact.

If the builder doesn't feed information back to the designer, then the incorrect figures just keep on being used.

Originally I was under the impression that Fastcat was one of the few meticulous builders who really did put the effort required into this, (Gideon claimed the boats are built on scales) but it seems not to be the case, if the boat suddenly weighs nearly 3 tons more than anticipated.

3 tons can not be explained by a bimini and some extra anchor rodes IMO.

Alan
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Old 05-10-2008, 08:57   #110
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Quote:
Originally Posted by Nordic cat View Post
The proffessional NAs do a comprehensive weight study during the design process. This is used to ensure the correct trim, displacement etc. under a given set or sets of conditions.The draught/displacement tables are easy to make with the software that is used these days, but they are seldom published. What you sometimes will see published are the immersion rates in mms/ton or pounds/inch. But this is often only for a certain start displacement as the hulls are seldom vertical on the sides.

The problem is when the builders, don't build as specified, and the basic boat is heavier than it should be. This happens with both infused, vacuum-bagged and hand lay-up.

The next area of weight gain is probably the biggest problem to manage, all the things that go into the boat, be it deck hardware, machinery, wood trim, safety gear, batteries, chargers, whatever.

If the builder or the owner does this in an uncontrolled manner, the end result as is often seen, is a boat that is far over the originally designed weight.

Few builders document this during build, as it is not in their interests, nor do they get paid to do it. When the owner finds out the boat is way too heavy, they can never find out exactly why, so they learn to live with the fact.

If the builder doesn't feed information back to the designer, then the incorrect figures just keep on being used.

Originally I was under the impression that Fastcat was one of the few meticulous builders who really did put the effort required into this, (Gideon claimed the boats are built on scales) but it seems not to be the case, if the boat suddenly weighs nearly 3 tons more than anticipated.

3 tons can not be explained by a bimini and some extra anchor rodes IMO.

Alan

Hallo Alan

The weight of the standard boat was supposed to be 6500 kilo and it is that within 5 % margin
I do not know where your 3 tons originate but Butterfly weighted 8400 kilo including over 1900 kilo,s of options and extra,s If this is taken off the actual weight when lifted out we arrive at 6500 kilo, Angelo Lavranos estimate was 5273 kilo for a bare boat and we do not produce a bare boat.
All our parts are weighted and if we can save weight without decreasing strenght we will do so.

Greetings

Gideon

For David

Our water line is set for our maximum recommended weight of 11000 kilo loaded.
If a customer wants the waterline set to the 13250 kilo as is allowed by the CE noem we paint the waterline accordingly.
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