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	Metacentric height (Site not responding. Last check: 2007-09-10)
		The metacentre, or centre of buoyancy, is the centre of gravity of the volume of water which the hull displaces.
		The metacentric height is important because the righting force is proportional to the metacentric height times the sine of the angle of heel.
		A larger metacentric height on the other hand gives a ship a short roll period and good stability, but if it is too large the ship is "stiff" - uncomfortable for passengers because it quickly jumps back upright after a wave or wind gust which heeled it over has passed.
	bopedia.com /en/wikipedia/m/me/metacentric_height.html (385 words)

	Metacentric height (George Herbert)
		The other way is for the hull shape and height of the center of gravity to be designed in such a way that if it heels a bit to starboard, that the distance from centerline that the center of bouyancy moves is greater than the distance from centerline that the center of gravity moves.
		Metacentric height (GM) is the height from the center of gravity to the metacenter.
		If the metacentric height is positive then the center of bouyancy does rotate further than the center of gravity does when the ship heels over, and it's stable and will return to level (unless pushed over very far or hard).
	yarchive.net /mil/metacentric_height.html (775 words)

	Metacentric height - Wikipedia, the free encyclopedia
		The metacentre is the point where the lines intersect (at angle φ) of the upward force of buoyancy of φ ± dφ.
		Technically, there are different metacentric heights for any combination of pitch and roll motion, depending on the moment of inertia of the waterplane area of the ship around the axis of rotation under consideration, but they are normally only calculated and stated as specific values for the limiting pure pitch and roll motions.
		The metacentric height is normally estimated during the design of a ship but can be determined by an inclining experiment or Inclining test once it has been built.
	en.wikipedia.org /wiki/Metacentric_height (954 words)

	Transverse Stability: Details (Site not responding. Last check: 2007-09-10)
		The transverse metacentric height (GMT), commonly called the metacentric height, of a ship is the vertical separation of the center of gravity and the transverse metacenter (see Figure 1-4) and is a primary indicator of initial stability.
		Metacentric height is calculated by subtracting the height of the center of gravity from the height of the metacenter above the keel:
		The transverse metacentric radius (BMT) is the vertical distance between the center of buoyancy and the metacenter.
	web.nps.navy.mil /~me/tsse/NavArchWeb/1/module7/details.htm (971 words)

	Shipbuilding - LoveToKnow 1911
		the height of the metacentre above the centre of buoyancy is equal to the moment of inertia of the water plane about the axis of rotation divided by the volume of displacement.
		The metacentric height is affected by an alteration in displacement or in position of the centre of gravity caused by loading or unloading cargo, fuel and stores.
		The height of the metacentre varies with the moment of inertia of the water-plane about the axis of inclination, and the maximum and minimum heights are associated with the maximum and minimum moments of inertia, which again correspond to inclinations about the least and greatest axes of inertia respectively.
	www.1911encyclopedia.org /Shipbuilding (15442 words)

	Hansa International Maritime Journal
		In Part Eight it was shown that the effect of a free liquid surface on the initial stability is equivalent to a reduction in the metacentric height and the reduction of the GZ curve at angle f.
		The practice of using metacentric height as the index of stability has been adopted to avoid the necessity for more elaborate calculations, such as those involved in preparing cross curves, and is based on the assumption that adequate metacentric height in conjunction with adequate freeboard will assure adequate righting moments.
		In such cases, if the effect of free liquid on metacentric height was to be evaluated by assuming that the center of gravity of the liquid in each of the tanks was at its metacenter, a gross exaggeration of loss of righting moments would be obtained at angles beyond 1 or 2 degree.
	www.hansa-online.de /artikel.asp?ArtikelID=587 (1073 words)

	NACA UK Mirror report description page (Site not responding. Last check: 2007-09-10)
		Upon plotting these metacentric heights against the corresponding gross weights, it appears that the metacentric height is approximately a straight line function of the gross weight.
		For the lateral metacentric height GM = 13 +.002 W and for longitudinal metacentric height GM = 15 +.002 W, GM is in feet and the gross weight (W) is in pounds.
		It is recommended that the longitudinal and lateral metacentric heights be made equal and of the value given by GM = 15 =.002 W. The proper length or spacing required to satisfy the indicated value may then be obtained from substitution in the approximate formulae for metacentric height.
	naca.central.cranfield.ac.uk /report.php?NID=506 (152 words)

	System for automated monitoring of trim and stability of a vessel - Patent 4872118
		To determine the metacentric height from a heeling test, it is necessary to know the inclining moment, the displacement of the ship and the heel angle increment which the ship attains due to the inclining moment applied thereto.
		With a great value of the metacentric height, on the other hand, the constant heeling moment causes a heel angle whose value is too low --as low as 0.3.degree.-0.4.degree.--and is commensurate with an error in measuring the heel angle increment.
		The respective outputs of the sensors 22, 24 and 25 are connected to the fourth group of inputs of the signal conditioner 5 having its multichannel data output connected to the multichannel data input of the interface 6.
	www.freepatentsonline.com /4872118.html (5979 words)

	::Selene Ocean Trawlers [Design Note] (Site not responding. Last check: 2007-09-10)
		Metacentric height is a measure of the vertical distance between a yacht's center of gravity and its "metacenter".
		The distance between these two points is called the Metacentric height, and is a measure of stability (resistance to heeling).
		Metacentric height is also affected by loading—both the amount of weight and it's location, so both unloaded and fully loaded Gm values are sometimes provided.
	www.selenetrawlers.com /NewSite/DesignNote_HydrostaticData.html (1495 words)

	MV ESTONIA - final report CHAPTER 5 THE CIRCUMSTANCES OF THE VOYAGE (Site not responding. Last check: 2007-09-10)
		Significant wave height is defined in the numerical models by the area under the wave spectrum, but is very close to the statistical measure of the mean value of the highest one-third of the waves.
		Table 5.4 shows the significant wave height Hs, spectrum peak or modal wave period Tp, and the mean direction of the waves predicted by the Finnish, Swedish and German institutes of marine research before, during and after the accident.
		Numerous studies of wave statistics in a seaway show that during a short interval when the significant wave height may be assumed constant, the distribution of measured wave crest-to-trough heights and heights of individual wave crests and troughs follow closely the Rayleigh distribution.
	www.webandwire.com /chapt05.html (2685 words)

	Metacentric Height
		I've been asked by a few of our friends here to explain what metacentric height is and why it is important in estimating warship stability.
		To calculate the metacentric height (B) is subtracted from (G) to give the metacentric height (GM).
		Ships have two metacentric heights, one being the transverse metacentric height (GMt) calculated using the transverse cross-section of the ship and the other the longitudinal metacentric height (GMl) using the longitudinal cross section of the ship.
	www.navweaps.com /index_tech/tech-009.htm (937 words)

	Eastland Memorial Society (Site not responding. Last check: 2007-09-10)
		The height and weight of the superstructure, according to competent marine architects, was out of proportion to the body of the vessel.
		The greater the metacentric height--or in other words the farther the center of gravity is below the buoyancy point of the vessel--the farther it may list to one side or the other without danger.
		In the case of the "Eastland," the metacentric height is alleged to have been only four inches.
	www.eastlandmemorial.org /pm1915_0.shtml (1297 words)

	Metacentric Height - Boat Design Forums
		BM (centre of buoyancy to metacentric ht) calculations are relatively straightforward for rectangles as described in the posting above...
		The metacentric radius is BM = I / V where V is the displaced volume.
		The metacentric height is calculated as follows GM = metacentric radius + vertical center of buoyancy - vertical center of gravity.
	www.boatdesign.net /forums/showthread.php?t=5696 (625 words)

	S.I. No. 102/1967: MERCHANT SHIPPING (GRAIN) RULES, 1967.
		"metacentric height" means the distance between the transverse metacentre (M) and the centre of gravity (G) corrected for the free surface effects of liquids in tanks, and, for the purposes of paragraph 4 (3) of this Schedule, for the free surface effects of grain in feeders;
		In this case the effects of the additional free grain surfaces within the feeders due to the omission of centre-line divisions shall be taken into account in calculating the metacentric height referred to in sub-paragraph (c) of paragraph 3 (2) of this Schedule.
		At intermediate feeder heights or lengths the maximum unsupported span of 2½ inch boards shall be obtained by interpolation.
	www.irishstatutebook.ie /ZZSI102Y1967.html (3269 words)

	Phils rc Models,trucks,boats,1/12th scale severn lifeboat
		The height h of this point above the centre of gravity G is known as the metacentric height.
		The greater the metacentric height the greater the righting level for any given angle of roll and the righting force resisting roll and therefore the greater the stability.
		Typical figures for metacentric height for a flower class corvette is 1.6 ft., whilst for a battleship it is typically 5ft..
	www.philsrcmodels.co.uk /ScaleInformation.html (3267 words)

	.:: THE BANGLADESH OBSERVER - Net Edition ::. (Site not responding. Last check: 2007-09-10)
		To prevent a ship from sinking watertight integrity of the ship is to be maintained and the stability of the ship, which is expressed as 'metacentric height' is to be maintained within safe limit.
		A moderate metacentric height is to be maintained by suitable loading plan of the vessel.
		If during a sudden rough weather passengers rush to the lower decks, vessels metacentric height reduces; the vessel may capsize by external force of violent storm or water wave causing the vessel to sink.
	www.bangladeshobserveronline.com /new/2005/05/15/ltte.htm (1374 words)

	Stabilising systems
		A vessel will roll due to the force of the waves.The actual effect of a wave system is dependent upon wave period, magnitude, ships metacentric height and displacement and others.
		All ships have a natural roll period depending upon; metacentric height, and the radius of gyration about the longitudinal polar axis.
		A large metacentric height will produce a short roll period which can be very uncomfortable whilst a small metacentric height produces slow roll periods with large amplitude.Both conditions can cause problems and reducing the roll amplitude is seen as advantageous.
	www.marineengineering.org.uk /navarch/navstabmain.htm (1095 words)

	[No title] (Site not responding. Last check: 2007-09-10)
		MG = Metacentric Height GL = The righting lever, tending to return the ship to her original position of stable equilibrium.
		Under normal circumstances the metacenter height (MG) for vessels loaded with a homogeneous cargo down to her marks will be at least 12 inches.
		If the metacentric height exceeds the normal limited the vessel will be stiff and will roll heavily in bad weather at very short intervals, subjecting the ship to heavy strain, which may cause damage to the ship’s structure apart from the risk of shifting of cargo through excessive rolling.
	home.earthlink.net /~marinerbill/knowledge/navigation/stability-info/metacentric-height-and-buoyancy.doc (859 words)

	Physics Help and Math Help - Physics Forums - View Single Post - Metacentric height correction due to free surface ...
		The structure is divided in two symmetrical parts by a wall running on the longitudinal axis.
		So we have the concrete box structure with two empty tanks (20 by 5) that we are going to float (assume that height is sufficient, let's say 15m).
		Metacentric height without considering the free water surface effect will be
	www.physicsforums.com /showpost.php?p=322675&postcount=3 (307 words)

	5 Some numerical values
		From Table 2 it is evident that the balancing moment of a plate of doubled size increases by more than an order of ten (more than twenty times), and for a cylindrical plate of 20 cm in diameter the metacentric height becomes about 0.4 m.
		This can then be comparatively flat and of minimum height; and the surfaces of the plate being parallel planes conform to the requirement that the mirror and a horizontal plane be parallel.
		Doing so would lower the the centre of mass of the whole body, increasing thereby its metacentric height, and thus the balancing moment.
	www.edpsciences.org /journal/index.cfm?v_url=aas/full/1998/15/ds1485/node5.html (507 words)

	License help for Canadian engineers - 1st Class ME Naval Architecture
		The distance between the center of lateral resistance and the center of the rudder is 1.7 m and the ship's metacentric height is 0.26 m.
		The center of gravity is 7.2 m above the keel, the transverse metacentre is 7.6 m above the keel and the center of buoyancy is 3.9 m above the keel.
		Neglecting the effect of free surface calculate the transverse metacentric height if water of density 1000 kg/m3 is pumped into both end compartments to a depth of 2 m.
	www.dieselduck.ca /library/exam_stuff/1st_naval_arc.01.htm (7582 words)

	Swift Kayaks - Articles & Tips
		An important measure is the metacentric height or GM.
		The metacentric height is the distance between the center of gravity and the metacenter which is the intersection of a vertical line drawn through the heeled center of buoyancy at a small angle of heel (usually less than ten degrees) and the same line for the upright condition.
		This is not a problem in large non-breaking waves (waves longer than twice the boat's beam and ten times longer than the wave height) but when the waves shorten to approximately 1.5 times the beam and less ten times the wave length in height the boat’s motion becomes quick and uncomfortable.
	www.swiftcanoe.com /kayak/article_results.asp?ID=4 (1435 words)

	Eastland Disaster Historical Society - Probable/Possible Causes (via CobWeb/3.1 planetlab2.cs.virginia.edu) (Site not responding. Last check: 2007-09-10)
		This caused the Eastland to be very unstable in the water, a result of its short metacentric height.
		After the metacentric height was determined during the engineering and design, 60 feet of length was removed from the Eastland (thereby making it less buoyant); it was also built with one additional deck (thereby making it more top heavy).
		No tests were performed by the builders or the inspectors to calculate the actual metacentric height of the Eastland until years after the disaster.
	www.eastlanddisaster.org.cob-web.org:8888 /causes.htm (1220 words)

	[No title]
		The initial metacentric height or metacentre, M, is calculated based on the centre of buoyancy, KB, and the moment of inertia of the ship’s waterplane, BM.
		Then GM is the vertical distance between the centre of gravity and the metacentre and is linearly related to the righting arm by the sine of the heel angle.
		at all times during a voyage the metacentric height GM0 should be positive after correction for the free surface effects of liquid in tanks, and, where appropriate, the absorption of water by the deck cargo and/or ice accretion on the exposed surfaces.
	www.gidb.itu.edu.tr /staff/akyildiz/CHAPTER9.doc (2543 words)

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