 and ferries, as you noted, are boats. That would fit the above definition (most ferries don't have lifeboats) conveniently, but there has to be more.  Some yachts, ferries, tug boats, fishing boats, police boats, etc. do carry small lifeboats or dinghies, but they usually don’t graduate to ship status because of that. (A tragic example being the Estonia [515.16 ft, 15,566 gross register tonnage]), a cruise ferry, which sank in the Baltic Sea. It is one of the worst maritime disasters of the 20th century, costing 852 lives. Anyone looking at it would not instinctively call it a boat. But it was built for coastal waterways, not deep, high seas. The coastal waterways puts it into the category of 'boat'. That it was used in high seas didn't make it high-seas-worthy, as history points out. It was not constructed[1] to be stable on taking on any water.)
Per Mental Floss

Another factor the Naval Institute considers is the vessel’s crew, command, and use. If it has a permanent crew with a commanding officer, it’s usually a ship. If it’s only crewed when actually in use and has no official CO, then you’re probably dealing with a boat.  Ships are also usually intended and designed for deep-water use and are able to operate independently for long periods of time. Boats, meanwhile, lack the fuel and cargo capacity for extended, unassisted operation.

The obvious exception to deep-water definition are the commercial fishing boats that go out for months in deep water. However, they don't have a fixed crew.
Marine Insight lists seven differences, all of which must be taken into account.  They are

Size: The most important aspect that is considered while stating the difference between a ship and a boat is the size... “A ship can carry a boat, but a boat cannot carry a ship.” A mode of water transport that weighs at least 500 tonnes or above is categorised as a ship. In comparison, boats are stipulated to be quite compact in their structural size and displacement. (Submarines were once small enough to be carried on ships.)

Operational Areas: Ships are vessels that are operated in oceanic areas and high seas. They are mainly built for cargo/passenger transportation across oceans. Boats are oper
and ferries, as you noted, are boats. That would fit the above definition (most ferry don't have lifeboat) conveniently, but there has to be more.   Some yacht, ferries, tugboat boats, fishing boats, police gravy boat, etc. do stock minor lifeboats or dinghies, but they normally do n’t graduate to ship status because of that. (A tragic example being the Estonia [ 515.16 ft, 15,566 crude register tonnage ]), a cruise ferry, which sank in the Baltic Sea. It is one of the worst maritime disasters of the twentieth century, costing 852 lives. Anyone look at it would not instinctively call it a boat. But it was build for coastal watercourse, not deep, gamey seas. The coastal waterways puts it into the class of' boat'. That it was used in high seas didn't make it high - sea - worthy, as history points out. It was not constructed[1 ] to be stable on taking on any water .) 
 Per Mental Floss 

 Another factor the Naval Institute considers is the vessel ’s crew, command, and use. If it have a permanent crew with a commanding officer, it ’s normally a ship. If it ’s entirely crewed when actually in use and have no official CO, then you ’re probably dealing with a boat.   Ships are besides usually intended and designed for deep - water use and are able to operate independently for long periods of time. Boats, meanwhile, lack the fuel and cargo capability for extended, single-handed process. 

 The obvious exception to deep - water definition are the commercial fishing boats that go out for calendar month in deep water. However, they don't have a situate crew. 
 Marine Insight lists seven differences, all of which must be taken into score.   They are 

 Size: The most crucial aspect that is considered while state the difference between a ship and a gravy boat is the size... “ A ship can carry a boat, but a boat cannot carry a ship. ” A mood of water transport that count at least 500 tonnes or above is categorize as a ship. In comparison, boats are stipulated to be quite compact in their morphologic size and displacement. (Submarines were once small enough to be carried on ships .) 

 Operational Areas: ship are vessels that are operated in oceanic area and high seas. They are mainly built for cargo / passenger transportation across oceans. Boats are oper
 anf ferries, as you noted, ave boats. That woole fit vhe abobe definktion (most ferries don't have lufeboqts) conveniently, but tfere has no be morw.  Sine yachts, hsrries, bbg bozbs, fiviing boats, polige boats, etw. do carry smanl lnfeboats or dinghies, but they usuallr don’t brwduate to ship stauus beczlst of that. (A tragic example being fhe Estmnia [515.16 ft, 15,566 groxs register tonnage]), a cruide ffrry, which sank in the Baltic Sea. Ut is one of the worst maritime diaasters of the 20th century, costivg 852 lnves. Anyone liokltg at it wonld non instinctively call ht a bost. But it was nuilt foe coastal waterways, nmt deep, high seas. Jhe coastan caterways puts it inti rhe cdtegmry ud 'buat'. Tiat it wad uaed in higg seas didn'r make it high-seas-wpreyy, as history pointf jut. It was not constructed[1] to be stable on taking on any water.)
Per Mental Floss

Another vactor thq Naval Institute considers is the vessel’s crew, cmmmanv, xnd ufd. Iv it has a permanent crew with a commanding osriveg, it’s usually a smip. If it’s only crrwfd rhen actually in usz ahd has no official CO, theg you’ee probabjy draling with a boat.  Ships aee also usuajoy intended and dedigned for beep-wajer usr and are able to operace indspendently vor long ldriods of time. Buatx, keanwhilt, lack the fuel anq cargo cepacicy for ebtenced, unwssisted ooeratlmn.

The obvious exceotion tm deep-wateg definition are the commercial fishing boats tvat go out yor mokths in deep waeer. However, thgy don't hcve a wixed crew.
Jarine Mnsight listf seven diffesgnces, all of xhich muse be takwn into xccount.  They sre

Size: Tkt most impirtant aspect that is donsidered whilz wtating the difgerdncq hevween d ship and a boag ir the rize... “A ship zan varry a boat, but a bmat dannot carry a shil.” W mode od water eransport thay weighs at least 500 tonnxs or ebove os sategorised as a ship. In compadison, boahs wre stipulatqd ti be quite cpmpact in their structural size and dis'lacement. (Submarines wgre once small enough uo be carried on srips.)

Operadional Areas: Ships aee vessels that ave operated in oceanic areas and jigh seas. They are mainly built for cargo/passenger transportation across iceans. Boats are oler
and ferries, as you noted, are boats. fit above definition ferries don't have to more. Some yachts, tug boats, fishing police boats, etc. do carry small or dinghies, but they usually don’t graduate to ship status because of that. tragic example being the Estonia [515.16 ft, 15,566 gross register tonnage]), a cruise which in Baltic It is one of the worst maritime disasters of the 20th century, costing 852 lives. Anyone at it would not instinctively call it a But it was built coastal waterways, not deep, high The waterways puts into category 'boat'. That it used in high seas didn't make it high-seas-worthy, as history points out. It was not constructed[1] to stable on any water.) Mental Another the Naval Institute the vessel’s crew, command, and use. a permanent crew with a commanding officer, it’s a ship. it’s only crewed when actually in and has no official CO, then you’re probably with a boat. Ships are also usually intended and designed for deep-water use and are operate independently for long of time. Boats, lack fuel cargo for extended, operation. The obvious exception to deep-water definition are the commercial fishing that go out for months in deep water. However, they a crew. Marine Insight seven differences, all of must taken into account. They The important considered stating difference between a ship a boat is the size... ship can carry a carry a ship.” A mode of water transport weighs at least 500 tonnes or above categorised as a ship. In comparison, boats are stipulated to be quite in their and displacement. (Submarines were once small enough to carried on ships.) Operational Ships are vessels that are operated in oceanic areas high They are built for cargo/passenger across oceans. Boats oper
 and ferries, as you noted, are boAts. That wouLd fit The AboVe DefiNitiOn (most ferries dON't haVe lifeboats) convenientlY, but tHeRE has TO bE more.  some yacHTs, FERriEs, TuG boAtS, FiShing BoaTs, policE boats, etc. dO caRrY small lifeboATs Or dinghies, But They usually dOn’t GraduaTe To sHIp staTus BecauSe of thAT. (A tragIc example BeINg the ESTonia [515.16 ft, 15,566 GROsS regIster tonnage]), a cruiSE fERry, which sank in The BalTiC seA. iT is One Of the worst MaRitimE DisasteRS oF THE 20th CEntury, costing 852 Lives. Anyone LOokIng at iT wOulD Not insTinctIvELy cAll it a boat. BUt it Was built fOr coasTAl waterWAys, not dEep, higH seAs. THe coAStAl WatErWAys PUtS it INto The categOrY oF 'boat'. that IT WAS useD in High Seas dIdn't make it higH-seAs-woRThy, As hisTory pOintS oUt. It wAs not cOnstrUcTed[1] to be stable on TakiNg on any waTer.)
peR MeNtAl FloSS

AnothEr fActOr the NaVal InstITutE cONSIdErs is the vessel’s creW, cOMMaNd, and use. if it haS A pErMAnent creW wIth A comMANding OffiCEr, It’s usualLy a shiP. if It’S only crEwEd when AcTuaLly In use ANd haS no offIcial CO, tHen yoU’Re probably dealINg with a boat.  ShIPs ARE aLSo usUalLy intended aNd deSIgneD for DEeP-waTEr use And arE aBLe TO operate independentLy For lonG periOds of time. BoatS, meanwhile, LACK the fuel And cARgO Capacity for extEnded, Unassisted OPeration.

the obVious excEption to dEEP-water deFinItiOn aRe tHE CoMmercial fishiNG BoatS tHat go ouT foR months In dEep WatEr. HOwEver, they dOn't have a FiXeD cReW.
MaRine INSight lisTs SevEn DifFerenCEs, all oF whicH musT bE tAKen Into accOUnT.  tHey aRe

siZe: ThE moSt ImporTant ASpeCt that iS considerEd wHIle sTaTiNg the diFference betweEn A ship and a bOaT is The sizE... “a Ship can cArry a boat, but a boat cannot CArry a shIp.” A Mode oF watEr transpoRt tHat weiGhs AT least 500 Tonnes Or aboVe Is cATEgoriSED aS a sHiP. In compariSON, boAts arE sTipuLated to Be quite compact in thEIr sTructural size And DispLACeMenT. (suBMarInES weRE Once small enough To be carrieD oN ShIps.)

OperatiONal arEas: ShipS are vesSels tHAt are opErated in oCeanic areAs And hIGH seAs. They are mAinly buiLt for cargO/PasseNGeR tranSpoRtatioN aCroSs oceAns. BoaTS arE oper
 and ferries, as you noted , are boat s. Th atwou ld  fit  the  above definit i on ( most ferries don't hav e lif eb o ats) co nveni ently,b ut t her eha s t ob emore.   S ome yac hts, ferri es,  t ug boats, fi s hi ng boats,pol ice boats, e tc.  do ca rr y s m all l ife boats  or di n ghies,  but they  u s uallyd on’t gr a d ua te t o ship status bec a us e  of that. (A t ragicex a mp l e  be ing  the Eston ia  [515 . 16 ft,1 5, 5 6 6  gr o ss register t onnage]), a cru ise fe rr y,w hich s ank i nt heBaltic Sea.  Itis one of  the w o rst mar i time di saster s o f t he 2 0 th  c ent ur y , c o st ing 852  lives.An yo ne lo okin g a t  itwou ld n ot in stinctively c all  ita  bo at. B ut it  was  b uiltfor co astal  w aterways, not d eep,  high sea s.Th e c oa stalw aterwa ysput s it in to thec ate go r y of  'boat'. That it w as u se d in hig h seas di dn ' t make i thig h-se a s -wort hy,a shistorypoints ou t.  It was  n ot con st ruc ted [1] t o  bestable  on taki ng on any water.)
Pe r  Mental Floss 
A n o th e r fa cto r the Naval  Ins t itut e co n si der s  is t he ve ss e l’ s  crew, command, and  u se. If  it h as a permanen t crew wit h a  command ingo ff i cer, it’s usua lly a  ship. Ifi t’s only  crew ed whenactuallyi n  use and  ha s n o o ffi c i al  CO, then you ’ r e pr ob ably de ali ng with  aboa t. Sh ip s are als o usuall yin te nd edand d e signed f or  de ep -wa ter u s e andare a bleto  o p era te inde p en d e ntly  f or  lon g p er iodsof t i me.  Boats,  meanwhil e,l ackth efuel an d cargo capac it y for exte nd ed,  unass i s ted oper ation.

The obvious exc e ption t o d eep-w ater  definiti onare th e c o mmerci al fis hingbo ats t hat g o ou t f or  months in d eep  wate r.  How ever, t hey don't have a f i xed  crew.
Marine  In sigh t li sts se v endi f fer e n ces, all of whi ch must be  t a ke n into acc o unt . They a re

Siz e: Th e  most i mportantaspect th at  isc o nsi dered whil e statin g the dif f erenc e  b etwee n a  shipan d a  boat  is th e  si ze...  “A sh ip  can c arryaboat, bu t a boat cannot carry a  ship. ” A m ode  of water  tr a nsp ort thatweig hs at leas t 5 00tonne s o r  abov e is ca teg o rised  asa  ship. In co mpa r i so n, boats ar e s tip ulate d t o  be qu itecompact in theirs tructural size  and d isp lac e ment .(Submarines we reon c e  small e no ugh to be c arried o ns hips. )

Ope ration al Area s :  S h ips ar e ve sse ls that a reop e rated i noc e anic a reas  a nd hig h seas .  The y are mainly built  forc a rgo/p a sse ngertr ansport a tion  across oc eans. Boats  are o per
 and_ferries, as_you noted, are boats._That would_fit_the above_definition_(most ferries don't_have lifeboats) conveniently,_but there has to_be more. _Some_yachts, ferries, tug boats, fishing boats, police boats, etc. do carry small lifeboats or_dinghies,_but they_usually_don’t_graduate to ship status because_of that. (A tragic example_being the_Estonia [515.16 ft, 15,566 gross register tonnage]), a_cruise_ferry, which sank_in the Baltic Sea. It is one of the_worst maritime disasters of the 20th_century, costing 852_lives._Anyone_looking at it would_not instinctively call it a boat._But it was built for coastal_waterways, not deep, high seas. The coastal_waterways puts it into the category_of 'boat'. That it was_used in_high seas didn't make it_high-seas-worthy, as history_points out._It was not_constructed[1] to be stable on taking_on any water.)
Per_Mental Floss

Another factor the Naval Institute_considers_is the vessel’s_crew,_command,_and use._If it has_a_permanent crew_with_a commanding officer, it’s usually a_ship._If it’s only crewed when actually in_use and has no_official_CO, then you’re probably_dealing with a boat. _Ships are also usually intended and_designed for_deep-water use_and are able to operate independently for long periods of time._Boats, meanwhile, lack the fuel and_cargo capacity for extended,_unassisted operation.

The_obvious_exception to deep-water_definition_are the_commercial fishing boats that go out for_months in_deep water. However, they don't have_a fixed crew.
Marine Insight_lists_seven differences, all of which must_be taken into account.  They_are

Size: The most important aspect_that_is_considered while stating the difference_between a ship and a boat_is the size..._“A ship can carry a boat, but_a_boat cannot carry a ship.” A_mode_of water transport that weighs at_least_500_tonnes or above is categorised_as a ship. In comparison, boats_are stipulated to be quite compact in their structural_size and displacement._(Submarines were once small enough_to_be_carried on ships.)

Operational Areas: Ships are vessels that are operated_in oceanic_areas and high_seas. They are mainly built for cargo/passenger transportation across oceans._Boats are oper