Hi All: I was comparing my h376 to the h380 using the specifications on both the HOW and the Hunter web sites. Both hulls are supposed to be identical. However, even if they are not, the specs for the 380 on each site are different. Examples: LOA HOW - 37'3" Hunter - 38'3" Mast HOW - 60'1" Hunter - 59'6" Displacement HOW - 15,000 Hunter - 16,000 LWL Identical on both sites Sail Area HOW - 847 Hunter - 811 "P" measurement HOW - 49' Hunter - 46'8" .....and a few others. Keep in mind that these differences are from site to site. I have no idea if there are any differences in reality. Also, the HOW site has identical specs for both the 376 and the 380, which means the Hunter site and the HOW site have different specs for the same boat I would like to have accurate specs (especially mast height) for my boat. Any thoughts ?? Jeff
- Status
Mast height
Jeff, Mast Height for the 380 is 59'10", I measured. The 380 and 376 are not as similar as people think. Lots of changes were made though the basic hull was the same length, 37'3" NOT 38'3". Weights and tankages change during the life span of any boat, but my 380 weighs in at 16,500 lbs., 5 foot draft, 75 gal water, 35 gal waste, 30 gal fuel. Best way to get accurate info on your boat would be to try to get an old brochure from Hunter. I'm sure if you called customer service they'd have one from your year 376 since it's not too old. Bob Knott H380
Jeff, Mast Height for the 380 is 59'10", I measured. The 380 and 376 are not as similar as people think. Lots of changes were made though the basic hull was the same length, 37'3" NOT 38'3". Weights and tankages change during the life span of any boat, but my 380 weighs in at 16,500 lbs., 5 foot draft, 75 gal water, 35 gal waste, 30 gal fuel. Best way to get accurate info on your boat would be to try to get an old brochure from Hunter. I'm sure if you called customer service they'd have one from your year 376 since it's not too old. Bob Knott H380
fine print
If you look closely at a brochure, It'll say somewhere on it in fine print "specs subject to change without notice" which means they don't notify us or Phil when they make a change, which is a lot more often then you would think, especially in the models that have a long production run.
If you look closely at a brochure, It'll say somewhere on it in fine print "specs subject to change without notice" which means they don't notify us or Phil when they make a change, which is a lot more often then you would think, especially in the models that have a long production run.
Yeah, but.........
The HOW site and the Hunter site had different specs for the SAME boat...the 380. I checked after I found all the differences with the 376 and the 380. Also...Bob, did you actually measure the displacement on your boat ? Was there a scale attached to a lift ? Thanks.....Jeff
The HOW site and the Hunter site had different specs for the SAME boat...the 380. I checked after I found all the differences with the 376 and the 380. Also...Bob, did you actually measure the displacement on your boat ? Was there a scale attached to a lift ? Thanks.....Jeff
Jeff and displacement
Jeff putting a scale on the lift will tell you what the boat weight is not the displacement weight. Displacement weight is the weight of the water the hull will displace in the water
Jeff putting a scale on the lift will tell you what the boat weight is not the displacement weight. Displacement weight is the weight of the water the hull will displace in the water
water displ=weight of boat
Think you'll find that the boat will only displace the amount of water equal to what it weighs . . .hence weight and displacement are equal. Law of nature, physical science or something like that. However this weight will vary from what your boat weights because of all the extras that you've added.
Think you'll find that the boat will only displace the amount of water equal to what it weighs . . .hence weight and displacement are equal. Law of nature, physical science or something like that. However this weight will vary from what your boat weights because of all the extras that you've added.
Archimedes
According to Archimedes, the weight of the water a boat displaces is exactly the same as the weight of the boat, so long as the boat is floating. If it displaces less, it is under water.
According to Archimedes, the weight of the water a boat displaces is exactly the same as the weight of the boat, so long as the boat is floating. If it displaces less, it is under water.
Clyde is right
For a body that floats, weight of boat = weight of water displaced (displacement). An intuitive notion can be gained by thinking of the water pushed aside having to go upwards, against the pull of gravity. So, as Clyde suggests, a boat being lowered into the water achieves a state of balance (i.e., floats) at that point where its weight matches the weight of the water it displaces.
For a body that floats, weight of boat = weight of water displaced (displacement). An intuitive notion can be gained by thinking of the water pushed aside having to go upwards, against the pull of gravity. So, as Clyde suggests, a boat being lowered into the water achieves a state of balance (i.e., floats) at that point where its weight matches the weight of the water it displaces.
Displacement vs weight.
I responded to this issue once in the Cherubini Hunters columns. It might still be there. The specification of displacement is NOT automatically equal to the specification of weight (as in trailer loading weight). The two figures simply do NOT measure the same thing-- however, you will see that they end up being close enough at any given time that they can easily be equated. Displacement measures VOLUME, not weight. It is actually taken in cubic feet; one cubic foot of fresh water weighs 64 lbs (28.5 kg) and that can be quoted as a figure in pounds (or kg). All responsible designers specify displacement figures in FRESH water, which is heavier than seawater (which is 62 lbs) --this allows that the boat will therefore 'weigh less' in salty water. But displacement is still not weight!!!! Notice that the volume of the boat does NOT change whether in seawater or fresh-- the boat is still the same size and still displaces the same amount of fluid medium whenever it floats on DWL. The tricky part is that the WATER it's in weighs less-- AND brine is more buoyant. So the reality of it is that the boat in seawater pushes LESS water out of the way because of seawater's buoyancy-- it has NOTHING to do with weight, as on a scale. And therefore the seawater figure of displacement may appear less. My father (nor I) had nothing to do with the design of the 376 but given the plans and a plinometer I could calculate for you the true displacement volume, multiply it by 64 lbs per square foot, and determine if the discrepancy in the two figures given is from specifying seawater or fresh water. The one thing you must always bear in mind is that displacement does NOT reflect the weight of the boat-- it represents the weight of the water being pushed aside. The only truly accurate way to weigh your boat in the dry is to put it on a trailer and drive it over a commercial truckers' scale and then subtract the tare weight of the trailer. But for most everyday purposes you may assume that the freshwater displacement figure is analgous to the weight of the boat on land. Just don't go thinking they are automatically the same thing, because they are NOT. JC 2
I responded to this issue once in the Cherubini Hunters columns. It might still be there. The specification of displacement is NOT automatically equal to the specification of weight (as in trailer loading weight). The two figures simply do NOT measure the same thing-- however, you will see that they end up being close enough at any given time that they can easily be equated. Displacement measures VOLUME, not weight. It is actually taken in cubic feet; one cubic foot of fresh water weighs 64 lbs (28.5 kg) and that can be quoted as a figure in pounds (or kg). All responsible designers specify displacement figures in FRESH water, which is heavier than seawater (which is 62 lbs) --this allows that the boat will therefore 'weigh less' in salty water. But displacement is still not weight!!!! Notice that the volume of the boat does NOT change whether in seawater or fresh-- the boat is still the same size and still displaces the same amount of fluid medium whenever it floats on DWL. The tricky part is that the WATER it's in weighs less-- AND brine is more buoyant. So the reality of it is that the boat in seawater pushes LESS water out of the way because of seawater's buoyancy-- it has NOTHING to do with weight, as on a scale. And therefore the seawater figure of displacement may appear less. My father (nor I) had nothing to do with the design of the 376 but given the plans and a plinometer I could calculate for you the true displacement volume, multiply it by 64 lbs per square foot, and determine if the discrepancy in the two figures given is from specifying seawater or fresh water. The one thing you must always bear in mind is that displacement does NOT reflect the weight of the boat-- it represents the weight of the water being pushed aside. The only truly accurate way to weigh your boat in the dry is to put it on a trailer and drive it over a commercial truckers' scale and then subtract the tare weight of the trailer. But for most everyday purposes you may assume that the freshwater displacement figure is analgous to the weight of the boat on land. Just don't go thinking they are automatically the same thing, because they are NOT. JC 2
With some trepidation....
(How does one argue with an expert?) First, I can't recall seeing a "displacment" figure for a boat that was stated in cubic feet or cubic meters. They are all stated in lbs or kgs. A boat is made of stuff. Let's say the stuff weights 10,000 lbs. (Let's also assume that the stuff is more dense than water.) If you configure that stuff as a solid cubic blob and put it in the water, it will sink straight to the bottom of the ocean. It's waterline is, well.... not meaningful. This blob is displacing an amount of water that's equal to it's volume. Since it is MORE dense than water, then, obviously the weight of the water it is displacing is LESS than its own weight. Thus, displacement does NOT equal weight in this case. Now, let's take that same 10,000 lbs of stuff and configure it as a hollow box. (Somewhat like a boat, eh?) The resultant shape has a specific volume. The density of the object -- AS A WHOLE -- is the weight/volume (actually it's mass/volume, but for this exercise it doesn't matter). If the density of the whole thing is LESS than that of water, it will float. It will settle into the water up to a certain level and it will have a distinct water line. Where will that water line be??? It will be at the point on the object where the weight of the object equals the weight of the water that is being displaced by the volume of the object below the water line. In other words, the weight of the boat DOES equal the weight water being displaced!!! (As long as the object as a whole is less dense than water.) A boat floating in salt water will displace a larger volume of water (and have a higher water line) because the salt water is less dense. The weight of the water displaced will still be the same! (For that 10,000 lb "boat", it'll be 156 cubic feet of fresh water, vs. 162 cubic feet of salt water.) If you float the boat in a pool of liquid mercury, the water line will be VERY low.... yet it will STILL displace the same WEIGHT of liquid. It's just that the liquid is more dense. (Mercury weights about 845 lbs per cubic foot, so your 10,000 boat will only displace about 11.8 cubic feet of mercury.) Another example: If you put 20 of your best friends and 10 cases of beer on your boat, it will sink farther into the water. Why? Because you are increasing it's density. (Beer and friends weigh more than the air they displaced.) It is now displacing more water. How much more? Simply add the weight of the boat the weight of your friends the weight of the beer. This will hold true until you add so much that the density of the boat is greater than the density of water... and the boat sinks. (A nit: If you fill the boat with helium, you will decrease it's overall density... and it will float higher in the water... and displace less water. Yet the weight of the material that makes up the BOAT remained the same! So JC's right, right? Well... the TOTAL weight of the boat needs to account for the weight of air in the boat too! (The problem with this little bit of complexity is that the ocean
(How does one argue with an expert?) First, I can't recall seeing a "displacment" figure for a boat that was stated in cubic feet or cubic meters. They are all stated in lbs or kgs. A boat is made of stuff. Let's say the stuff weights 10,000 lbs. (Let's also assume that the stuff is more dense than water.) If you configure that stuff as a solid cubic blob and put it in the water, it will sink straight to the bottom of the ocean. It's waterline is, well.... not meaningful. This blob is displacing an amount of water that's equal to it's volume. Since it is MORE dense than water, then, obviously the weight of the water it is displacing is LESS than its own weight. Thus, displacement does NOT equal weight in this case. Now, let's take that same 10,000 lbs of stuff and configure it as a hollow box. (Somewhat like a boat, eh?) The resultant shape has a specific volume. The density of the object -- AS A WHOLE -- is the weight/volume (actually it's mass/volume, but for this exercise it doesn't matter). If the density of the whole thing is LESS than that of water, it will float. It will settle into the water up to a certain level and it will have a distinct water line. Where will that water line be??? It will be at the point on the object where the weight of the object equals the weight of the water that is being displaced by the volume of the object below the water line. In other words, the weight of the boat DOES equal the weight water being displaced!!! (As long as the object as a whole is less dense than water.) A boat floating in salt water will displace a larger volume of water (and have a higher water line) because the salt water is less dense. The weight of the water displaced will still be the same! (For that 10,000 lb "boat", it'll be 156 cubic feet of fresh water, vs. 162 cubic feet of salt water.) If you float the boat in a pool of liquid mercury, the water line will be VERY low.... yet it will STILL displace the same WEIGHT of liquid. It's just that the liquid is more dense. (Mercury weights about 845 lbs per cubic foot, so your 10,000 boat will only displace about 11.8 cubic feet of mercury.) Another example: If you put 20 of your best friends and 10 cases of beer on your boat, it will sink farther into the water. Why? Because you are increasing it's density. (Beer and friends weigh more than the air they displaced.) It is now displacing more water. How much more? Simply add the weight of the boat the weight of your friends the weight of the beer. This will hold true until you add so much that the density of the boat is greater than the density of water... and the boat sinks. (A nit: If you fill the boat with helium, you will decrease it's overall density... and it will float higher in the water... and displace less water. Yet the weight of the material that makes up the BOAT remained the same! So JC's right, right? Well... the TOTAL weight of the boat needs to account for the weight of air in the boat too! (The problem with this little bit of complexity is that the ocean
densities of water???
It has been quite awhile, but I distinctly remember that the feature of swimming in the Dead Sea (very salty), was that you floated HIGHER....so, isn't salt water more dense and heavy than fresh, rather than the other way around? I am tooooo tired to look it up!! Could be wrong, I suppose.
It has been quite awhile, but I distinctly remember that the feature of swimming in the Dead Sea (very salty), was that you floated HIGHER....so, isn't salt water more dense and heavy than fresh, rather than the other way around? I am tooooo tired to look it up!! Could be wrong, I suppose.
The official answer on displacement.
Displacement is based on the weight of the vessel. This should not be confused with "Tonnage" measurements, based on the volume of the vessel. This is a coast guard expalianation of tonnage verses displacement. "Gross and net tonnage should not be confused with displacement tonnage, which is measured in terms of long tons (2240 pounds per long ton.)" Use link below. Ted Brewer gives good explainations of design terms for yatchs. http://www.tedbrewer.com/yachtdesign.html
Displacement is based on the weight of the vessel. This should not be confused with "Tonnage" measurements, based on the volume of the vessel. This is a coast guard expalianation of tonnage verses displacement. "Gross and net tonnage should not be confused with displacement tonnage, which is measured in terms of long tons (2240 pounds per long ton.)" Use link below. Ted Brewer gives good explainations of design terms for yatchs. http://www.tedbrewer.com/yachtdesign.html
Displacement
With all the conflicting statements this thread was starting to intrigue me so I Googled a bit and came up with the following information: According to the definitions used by maritime law experts (e.g. <http://tetley.law.mcgill.ca/q-t.htm>) and maritime insurance companies ( <http://www.ponl.com/topic/home_page/language_en/about_us/useful_information/a-z_of_shipping_terms/D>) "displacement" or "displacement tonnage" is simply the weight of the vessel with all it's equipment, stores and personnel. In other words, it does not matter what the volume of the water is that is displaced (which will of course vary as a function of density, as correctly pointed out by several posters) but only what the weight of the displaced water is. I also learned that although Peter Albright is right in saying that tonnage is generally related to volume, not to weight, the two exceptions are "displacement tonnage" (apparently mostly used for warships) and "deadweight tonnage" (mostly used by shippers and insurers) both of which are measurements of weight. Flying Dutchman
With all the conflicting statements this thread was starting to intrigue me so I Googled a bit and came up with the following information: According to the definitions used by maritime law experts (e.g. <http://tetley.law.mcgill.ca/q-t.htm>) and maritime insurance companies ( <http://www.ponl.com/topic/home_page/language_en/about_us/useful_information/a-z_of_shipping_terms/D>) "displacement" or "displacement tonnage" is simply the weight of the vessel with all it's equipment, stores and personnel. In other words, it does not matter what the volume of the water is that is displaced (which will of course vary as a function of density, as correctly pointed out by several posters) but only what the weight of the displaced water is. I also learned that although Peter Albright is right in saying that tonnage is generally related to volume, not to weight, the two exceptions are "displacement tonnage" (apparently mostly used for warships) and "deadweight tonnage" (mostly used by shippers and insurers) both of which are measurements of weight. Flying Dutchman
Jeff , yes I did
Jeff, Serenity was weighed twice, 1st in 1999 and was 16,500 lbs with no water and 1/2 fuel. She was weighed when short hauled last summer during our summer cruise and as 18,875 when loaded for a two week cruise, full water, full fuel, 15 gallons of waste /- included out small dinghy. She also sits well over 1" lower in the water when loaded for a cruise. Bob Knott H380
Jeff, Serenity was weighed twice, 1st in 1999 and was 16,500 lbs with no water and 1/2 fuel. She was weighed when short hauled last summer during our summer cruise and as 18,875 when loaded for a two week cruise, full water, full fuel, 15 gallons of waste /- included out small dinghy. She also sits well over 1" lower in the water when loaded for a cruise. Bob Knott H380
- Status