Discussion in 'Hatteras Yacht' started by Marmot, Nov 25, 2013.
Are you sure the 150 tons was not referring to its displacement but to it's gross tonnage?
150 Tons in the US is 300,000 lbs somewhat heavier than now advertised where it is claimed to weigh 132 Tons.
Gross tonnage was 265 and Net tonnage 79. (Measured tonnage recorded on the documentation).
The vessel was going back into the water bow first supported on the steel cradle that is lifted and lowered by four winches. The concrete below the port forward winch collapsed causing the cradle to drop towards the forward end of the vessel.
The winches held the cradle up at the stern of the vessel and that is why the bow of the vessel was low in the water not because she was full of water.
The damage occurred outboard of the lower guest cabin vestibule on the port side just below the clothes dryer vent discharge.
FYI: 1997 Hatteras 116' is 380,000 lbs from a calibrated travel lift scale, with a recorded gross tonnage on the documentation of 221 tons and a net tonnage of 66. Sacajawea is a 1995 Hatteras 130 but I do not know what the displacement is.
The vessels stranded ashore after the incident included a house boat plus two wooden vessels one of which was the completely bare wooden Broward. It took months to clear the Well of the cradle and collapsed winch and then even longer to come up with a plan to lift the vessels back into water.
It is weight. Not tonnage
Yes, but I'm talking displacement and going from the published article and from the ads run for the boat. That's what is so surprising. +
What is the difference between what a vessel weighs when hanging in the straps of a calibrated travel lift to the amount it displaces in the equivalent units when re launched?
That's easy ...
a = G M / d^2 = G M / R^2 * (R/d)^2 = g (R/d)^2, where g is the acceleration at the surface of the Earth (9.81 m/s^2) and R and d are the radius of the Earth and the inter-center distance between Earth and the boat hanging on the straps.
Not sure I understand your question but assuming you're asking the difference between weight in slings on scale vs. tonnage for documentation then the former is weight while the latter is a calculation based on cube in the water and referring to the water actually displaced. The latter is typically far less than the former. The formula is available online but is quite involved and requires measurements not readily available to the public to actually calculate. It is also the measurement of tonnage used to determine requirements for crew.
In this case the relevant number is the former as we're comparing against the capacity of the lift. The reason it's relevant is that what I would expect a 130' Hatteras to weigh would exceed the capacity of a 200 pound lift. I would expect the Hatteras to weigh more than a Westport and I know the 130' Westport exceeds that lift capacity.
And it is insane that the term "displacement" is used for both measurements.
Oh, we get some Engineer humor. Well done, Marmot.
I am not sure you understand the difference between displacement and gross tonnage.
If the vessel weighs 300,000 lbs hanging in slings it will displace 300,000 lbs of the water is is lowered into.
This is the displacement of it.
That same vessel might have a Gross Tonnage of 450, this is a volumetric measurement and has no relationship to the actual weight of the vessel.
It is the Gross Tonnage that is used on the bigger vessels to determine the reqirements for the crew as well as the installled propulsion power in some cases.
The fact that you expect a particular used vessel of one manufacturer to weigh more than that from another is pure speculation.
He said he was talking about weight not tonnage, then that he was talking about displacement. That sounds like he was using weight and displacement interchangeably and distinguishing them from tonnage. I don't see why you take that to mean that he thought there was a difference between weight and displacement, or that he didn't realize that there is a difference between displacement and tonnage.
Edit: I did not see the comment that he made in post #28. I withdraw my statement.
Opcn, it would behoove you to know something about horses before picking a favorite ...
I know now that you don't understand any of the subject but for some reason insist on pretending and posting stuff like the following;
Gross tonnage, net tonnage, and Gross Register tonnage and Panama or Suez Canal tonnage have - now read carefully - absofrickinglutely nothing to do with anything related to water, weight, or displacement.
I am not going to waste my time attempting to explain something so fundamental to someone who has time to post nonsense but apparently not enough time to research the subject.
I didn't see the error, I posted not that he was correct, but that I didn't see the error. I went back and reread and noticed the error. I am a mere mortal.
Kiwi. I very much understand and I don't need to be quized by you on the subject. I think my follow up answer made it clear I do understand and I also think it is reasonable to question a 130' Hatteras on a 200 ton lift.
Register tonnage, water tonnage....none of those have anything to do with the discussion. I do understand the difference. The question is simply how much a Hatteras 130 weighs and if the number reported is accurate and if it is reasonable to use a 200 lb lift.
What do you cal the weight of the vessel when it is in the slings?
This is the actual weight that will break your lift if it is greater than the rating of your lift regardless of the weight indocated on the docs as a cubic measurement which itself has NO beraing on what the vessel weighs.
I do agree that a 130ft boat from any manufacturer will break a 200lb lift.
What in the world is "water tonnage"?
How can you understand the difference when you keep posting stuff that proves beyond any doubt that you don't have a clue what you are talking about?
Please, do the membership a favor and quit posting stuff like that. It dilutes the quality that made this site the premier yacht forum is has become.
There are many boating sites where you can post anything you like, true or false, reliable or worthless and no one is the wiser but this site demands a bit higher standard. Ask anything you want and you will get a civil answer no matter how basic the question, but if you insist on posting horsecrap as fact then expect to get swept up.
But are those pounds American, British, metric, Panama, suez, Timbuktu ?. CaptJ must be loving this for a change. Lol.
PS. K1W1, here in America we spell bearing (as in bearing in mind) or baring (as in bikinis on the beach) slightly different to "beraing".
There is no such thing as water tonnage.....just tossed it in to say nothing else was relevant to the point. The point is clearly the weight in the sling, which is the displacement. And it's the displacement as laden at the time. I do know displacement vs. tonnage and if using the word weight offends you then so be it. But the sling is rated based on that term. As to your comments, Marmot, I'll send you a message in private because I don't care to be as disrespectul in a public forum as you do.
You just were.
PM = PM
Notice of a PM on a Forum is not a true PM of the type you desire to send, unless you want others to be aware of your displeasure.