The Packard V-12 PT Boat Engine

Everyone knows the WW2 PT boat was a rocketship, and that it was powered with big, beefy engines. What many are unclear on is exactly what they were, and where they came from. In this video we go through the development history of the Packard M-2500 series of engines, and common misconceptions as to what they were.
No monkeys were harmed in the making of this video.
Chapters
0:00 Start
1:53 Liberty L12 engine
4:33 Packard 1A-2500
8:00 Packard 1M-2500 marine engine
Sincere thanks to Randy 'Motor Mac' Smith for the video clip of a 4M engine starting up.

[@johnjacobjingleheimerschmi3857]

My Grandfather worked for Packard Motor Company during WWII building Aircraft Merlin's. I still have his sterling silver lapel pins, a gold 10 year service award and a few of his Micrometers. The man never missed a day of work until he finally retired at 66. He is dearly missed.

[@mikegoodwin7115]

I worked with a japanese man in the late 70's who's grandfather had been in the japanese navy in ww2, he said they called the american PT boats , the green dragons and most sailors were scared shitless of them. They would seem to appear out of nowhere, you couldn't see them at night except by the wakes, and where so fast you couldn't train you're guns on them fast enough.

[@daffyduck9901]

🇺🇸💪

[@peedeenoodie]

In loving memory of McHale's Navy & the brave boys of the PT 73

[@johngillon6969]

Sadly, those boys probably didn't know that that was not a real P.T. Boat The boat shown in the show was actually a british patrol boat . They would show stock war footage of real p.t. boats, but the up close shots were the british boats.

[@perpetualgrin5804]

Great show😅.

[@sueneilson896]

Many fond memories of Ensign Parker accidentally shooting down a Nip Zero every episode.

[@WALTERBROADDUS]

​@@johngillon6969 Actually 3 boats used in the show. A 71ft. VOSPER and 2 63ft. Air sea crash boats..

[@mercoid]

This packed my ard.

[@allaboutboats]

Hi Les, great video! I am a crew on PT658 here in Portland OR. The purpose of the 5M-2500 engine aftercooler was placed on the engine in order to boost the horsepower up to 1850hp. Coupled with the larger diameter of the supercharger wheel and the higher speed of the supercharger give the increase in horsepower. The 4M-2500 has only 1500hp by comparison. One interesting problem that we have discovered with these engines is that we have inadvertently "snapped" 4 of these supercharger drive shafts. They are 1 inch diameter hardened steel splined shafts. What we found out was that when you either slow down or speed up the engine too quickly, the momentum of the supercharger in relation to the crankshaft is too high and the shaft can break very easily. So our new operating method is to slowly accelerate or decelerate when we go fast. We are taking the boat out here on 5-6-7 June 2024 for Portland Rose Festival Fleet Week, so it should be a lot of fun! All of your PT Boat related videos are very well researched and I am a fan. Thanks for these series of excellent videos! Jerry

[@chrisliving6438]

My grandfather was Bill North vs pres. Packard motor production. A 52 yr old widower in 42.:sent to London then, met a younger pub manager.brought home a war bride! My English grandmother. Thank god for all of them!!!! A crying shame Packard motor ended as a result of all of this.

[@richardmccaughey5928]

In the late '50's my father had a Navy buddy who stayed in after WWII. My dad turned down a commission if he reupped. The buddy, Newton by name was still a Chief Machinists Mate and was stationed at Port Hueneme (pronounced "why-a-nee-mee"), halfway up the coast from L.A. to Santa Barbara. Part of the complex was the Point Magoo Naval Air Station. I was about 12 years old and we would visit the Newton family fairly regularly. On one visit, Chief Newton had a really nice surprise for my one year older brother and me. Port Huaneme had a couple of converted PT boats that they used for "coastal patrols" (a totally useless exercise but since when has the military not engaged in useless exercises to play with their toys). To make a long story short, the Chief had arranged for us to "go for a ride". Two things stick in my mind from that experience. First was just how fucking fast that boat was. Second, we got to go down to the "engine room", an extremely cramped space almost fully taken up with those Packard V-12's. That was the loudest sustained noise I had ever heard in my life. I remember it today like almost a physical presence. No wonder so many WWII vets came home with hearing loss!

[@chrismcmahon7230]

Cool story and experience.

[@waynetaylor8082]

The contribution of PACKARD to the war effort is incalculable. That the company didn't survive the 1950's is truly a shame. Their place in history needs to be remembered and honored.

[@truthseeker289]

I worked in a shop that reworked several crankshafts for the Navy they were works of art. Every surface was machined hollow rod and mains stainless steel.

[@petekane2501]

My grand father Joe Carville was a engine mechanic on these PT boats . He had plenty of stories about his time in pacific. During his service he became friends with JFK as he was a Boston man.

[@JosephStately]

From what I read the engines required quite a bit of maintenance. Great to hear he shared the stories with you.

[@stepanbandera5206]

As a PT Boat "Splinter" attending numerous PT reunions with my father, I must thank you for creating this video. I appreciate the effort you put into this.

[@RadioReprised]

In the late 60's and early 70's these boats would come into our Marina on the Salton Sea from the Naval Target Range and refuel! As a kid, the sound was AMAZING and the size of this boat combined with the speed when they went hammer down as they left impressed me to this day!

[@rhondadickey7158]

My dad was a WW2 PT Boat machinist in the Pacific. He served in the same squadron as Kennedy. The most hazardous naval duty in the war. He had three boats he served on sunk. On one, he was the only survivor. Needless to say, he suffered with PTSD. PT boaters are all heroes.

[@EldredTGlass]

I remember hearing those three Packard engines on ELCOs first prototype on her second trip down the Thames River out to theSound for Testing what a beautiful Roar will never forget.😊

[@johnbattista9519]

Nice.

[@maxxod1]

I had a rare opportunity to help rebuild a Packard Merlin that was for a Lancaster bomber and what a treat it was. When I say “help” I mean I was basically the gopher for the guys that really knew what they were doing but at 23, I was more than happy to help.

[@Hydrazine1000]

I once read a story on those PT-boats and their engines. Myth/rumor has it that they were secretly/not-so-secretly tuned/optimized/hot-rodded by some crews because, after a drill at sea, they would sometimes be allowed to race full-throttle back to port, and the fastest boat would get to sea-spray on those in chase. It might just have been a bar story, but I still like the thought of mechanics tinkering to get the very best out of those V12s.

[@bloqk16]

There is that story of PT 109 with JFK that the refueling of the boats was determined by the order of arrival; meaning the first boat in would be the first one refueled. The last PT to arrive for refueling may have a wait time of hours before refueling.

[@LesSharp]

I hadn't heard that one, but it makes good sense. Luckily with superchargers it's not as easy as tampering with a wastegate to bump up the boost, so they're probably only able to tweak timing and mixture settings to optimize operation, which shouldn't harm the engine.

[@JoeBob461]

In the clips from "They Were Expendable" we see Robert Montgomery, who was an actual PT boat sailor/veteran.

[@msamour]

I loved that movie. One of my top 25 movies of all times. Hollywood actors of the 40's and 50's were actual war vets, and they were really credible having lived the real experience.

[@stepanbandera5206]

Robert Montgomery was also the father of Elizabeth Montgomery (Bewitched).

[@dartskipper3170]

Hubert Scott Payne who owned the British Power Boat Company had converted some R.R.Merlin engines for use in his early MTB's. When he learned that all Merlin engines were to be reserved for aircraft production he went to the USA in search of a replacement. He took plans of his boat designs which were the inspiration for the Elco designs. This steered him towards the Packard engines and he secured some for his company. They were so successful that the British Government entered a Lease Lend contract for the Packard engines for Coastal Forces and were used by Vosper when they lost the supply of the Italian Isotta Fraschini engines they had distribution rights for prior to war being declared.

[@Dr_Reason]

50 degree ignition advance indicates slow burning fuel and not a lot of combustion turbulence. Still a glouriosly smooth engine with a great sound.

[@lightbox617]

Very thoroughly and nicely produced. Great, serious information and explanatory work. I live about 8 miles down rt 440 in Bayonne and regularly visit the Boat lift built to put PT boats into the water at the end of the Hackensack and Passaic rivers where the empty into Newark Bay . Thanks

[@davidtasker6729]

Was a harbor security mech in Subic, remember hearing rumors from old timers of security boats that had Packard engines. They said that after Vietnam that they were replaced by PBRs. They said those Packards could scream but were a maintenance nightmares. They still had the engine hoists and boat skids. They even had the old AVGAS tanks, still sealed. I sure would have liked to see them but I did get to work on the PBRs. Lots of fun.

[@patrickshaw8595]

As a hardcore IC recip engine man I thank you for posting this and setting the record straight. It was needed and you seem to be just the guy to pull it all together. Good Job !

[@ludwigsamereier8204]

OMG "They Were Expendable" is THE movie for this outstanding engine.

[@rickmcdonald1557]

Yes this version was much easier to follow audio wise and appreciated your efforts~!

[@LesSharp]

Glad to hear that!

[@Buck1954]

Much better audio, thank you. A good documentary on an interesting subject.

[@LesSharp]

Glad you enjoyed it

[@shawntailor5485]

Brad Taylor ,Hi cousin ! Small world lol.

[@theknifedude1881]

I’m USN ‘61-‘63(reserve). I was a SCUBA diver,collector for the Marine Biology Museum @ Pt. Mugu, California. There are 5 Channel Islands offshore and the Navy (Pacific Missile Range) has a presence on several of them. The Navy still had several WWII PT Boats which were used for mail and supply delivery and we(3 divers,collectors)could beg a ride. Occasionally, usually dropped to dive off a couple of inner tubes and picked up on their way back. Very occasionally we would be able to dive off a “Live Boat”(Opening Day of the lobster season 1963. Two lobsters, just the tails, 12# on the bathroom scales)! These had Packard engines(3).

[@LesSharp]

I'm also a diver and can only imagine the grins you'd be wearing while diving off a PT boat!

[@JosephStately]

Saw one on display at Battleship Cove in Fall River, Massachusetts. Very cool. Also 2 fully restored PT boats are on display there.

[@stepanbandera5206]

Battleship Cove is a must see for WWII naval historians! The Higgins was actually in JFK's inaugural parade (PT 109 was actually an ELCO). There is also a PT museum inside the battleship Massachusetts.

[@madmanmechanic8847]

You listen to the engine in some of these old footage when they are idling and you hear the cam through the thru hull exhaust give a gear head a rise in the Levis. These engines were so far ahead of there time

[@RivetGardener]

Great video and these engines were something else....legendary in their power and craftmanship!

[@maxdevlin4349]

Narration is much clearer, thank you! Those engines were functional art... Have been sharing your channel to my retired Navy friends, men of various talents from boat restoration to museum quality model ship builders.

[@LesSharp]

Thank you so much! If you guys have any photos to share I’d love to see them!

[@maxdevlin4349]

@@LesSharp I'll have to ask Dave, he might have some personal Vietnam era PT boat pictures.

[@everettrhay4855]

I spent some time in the engine space aboard PT-658 while underway. It was every bit as awe inspiring as you could imagine. The throttle plates were just barely cracked open, as we were only doing about 15 knots. Conversation in the engine space was impossible, we just stood there with big stupid grins on our faces.

[@bogthing1]

My neighbor served on PT Boats in Mindanao. I was curious about it and asked about the experience. (when I was a kid). He looked at me oddly, and said simply, "it was hot". Then he turned to my father, as though he had asked the question, and said. "they had us fueling them with goddamn jerry cans". Years later, when I was a sailor, I came to appreciate what he'd said.

[@LesSharp]

"It was hot" LMAO! Yeah, filling several thousand gallons by hand when it's 100*F and 100% humidity would absolutely suck. Where I lived, you could see Mindanao on a clear day, so I know.

[@JungleYT]

*Would have been nice to hear some of that legendary droning sound...*

[@edwardpate6128]

I just saw the Miss America X being towed on a trailer near Lake St. Clair in MI. A direct connection to the PT engines.

[@LesSharp]

One of the things I didn't know when making this video was that the Liberty engine was a cheap and cheerful powerplant for smuggling boats during Prohibition. I wonder who inspired who?

[@williambikash6645]

@@LesSharp The current production Florida built Cigarette boats are named after a prohibition era rum runner that was nicknamed Cigarette or was called Cigarette because it was long and thin. I doubt if they lettered the name on the "Cigarette " rum runner !

[@williambikash6645]

@@LesSharp Back around 1969 I worked with a boat mechanic in a Ft Lauderdale boat yard who as a young man worked on a Detroit rum runner tuning up the multiple Liberty engines. He was a young man at the time and was paid with hundred dollar bills. He said he didn't know what to do with bills that large. Ernie Riley was quite the character with an Irish glint in his eyes and full of great stories. Also possibly the world's largest leprechaun!

[@user-hu7nz7oj1j]

Fabulous history lesson and film clips ! Thank you !

[@privateer0561]

The monkeys have no tails in Zamboanga sung at the very end was a song my uncle sang when stationed in New Guinea during WW2; just died a short time ago at 97. I'm guessing my father did as well, although he never spoke of it; he died more than 37 years ago.

[@steveshoemaker6347]

Sorry for your loss of him....l am in my 80's.... Shoe🇺🇸

[@onslought2]

My father was a PT driver known as the river rat in Vietnam three month before he retired.

[@MrJohnestall]

Really interesting film , thank you !

[@jamesmulanax1424]

Interesting. In my younger years as a Sea Scout, we had a 1942 Chris Craft Army J boat. At 42 feet, she had anti-aircraft guns on the fore and aft decks. Supposedly, the motor was a left-over Liberty V-12, and after watching this video, I wonder if it was actually a Packard. The semi-planning hull boat was stationed in San Francisco Bay, had six 220-gallon gas tanks, a 23-inch left hand propeller, twin water-cooled brass exhausts tubes, and accommodated 12 sailors. By the time I was affiliated with it, four gas tanks were removed, the motor replaced with a Detroit Diesel 6-71 with a battle governor, and one of the exhaust tubes plugged though still remained. Even with its diesel and 120 mm injectors, she was quite a fast 8-ton boat in Humboldt Bay where she remained until rotted to the point of destruction. I miss those days growing up on the water!

[@dpeter6396]

Dad was MoMate PT 156 plank owner. Miss him very much.

[@tejastiger61]

Howdy fellas, very impressive, one of the absolute best KZbin format docs….. One million thank you’s for this great video. B R A V O …! Well Done …! Top notch .., TOP NOCH …!

[@jimkenty5306]

My dad was aboard PT-335 in the South Pacific. While he was away, my mom took me (about age 4) to see a PT at a lake, where we were going to take a ride. We were close to the boat when the engines started up with a roar. It scared the bejeezus out of me, and there was no way I was getting on that darned thing!

[@mickvonbornemann3824]

Well I remember reading somewhere RR suggested Packard should get the contract for US built Merlins because they were the only American firm that they had confidence in, due to their prior experience building V12 engines. This certainly implies that Packard were building V12s before they were building Merlins.

[@paulplack490]

@9:56 - It did not have two plugs per cylinder because of its aero heritage, but because they were required to completely ignite the mixture across a piston face 6.375 inches in diameter. The redundant ignition benefit was just a bonus, as losing spark to one set of plugs would noticeably reduce power output..

[@rosiehawtrey]

Sorry, but in order to be qualified as an aero engine they have to have two full ignition systems. Which is why when you start an 1820 you do a mag test and if the engine stalls on either circuit its a scrub. They probably just kept the system because it would have required a lot of mucking about and new parts (to do it properly) and a loss of power to boot.

[@LesSharp]

Packard did try to implement some form of automatic timing advance/retard in order to simplify operation for the motorman, but it was primitive and didn't work out. They reverted to manual control and that was that. I do believe that running the motor on only one spark plug per cylinder would indeed drop output, considering that ignition advance was as high as 50*BTDC. As someone else pointed out, that shows you how slow flame front propagation was, and chances are good that with only one ignition source that peak cylinder pressure would come so late on the power stroke as to cripple output. Magnetos are a pain to work with, but the advantage is not needed battery power to run ignition coils. Boat builders like ELCO were probably not about to start messing with drop-in units supplied by the anointed Navy supplier.

[@Rev1Kev]

My grandfather worked at Packard in Detroit, from 1925, until his retirement in 1952

[@andyharman3022]

Packard went bankrupt before I was born, but I miss their presence in the auto industry to this day. They had some excellent engineering in their cars and engines.

[@timhallas4275]

It's rather amusing in the 2000s, hearing about a 16 liter v-12 gas engine that makes 800 HP, and cost $20,000 in the 1940s, considering that we get 800hp out of a v-8, 5.7 liter gas engine that cost under $3,000 to build today.

[@keithstudly6071]

How many hours will it run while producing 800HP?

[@timhallas4275]

@@keithstudly6071 Average is 500 racing hours between full rebuilds. or the street version only puts out 500 hp and averages 5,000 hours between overhauls. My point was, $20,000 in the 1940s is equal 200,000 in 2020s dollars. With that much money, I could replace my 800hp engine after every race with a brand new one.

[@keithstudly6071]

@@timhallas4275 Well my point is that the way racing engines and automotive engines in general are rated is very differently from aircraft or marine practice. An aircraft engine is tested for a minimum of 100 hours at it's rated power. That's producing 800 HP on the dyno and held at that power for 100 hours. That's just the start. Automotive practice is just producing the rated power for a few seconds. Automotive engines are rarely producing full power even for 1/2 the time they are running, even if they are being used for racing purposes. The PT boat engines were running between 60 and 100 percent power for their rated 750 hour time between overhaul. To get that kind of service from an automotive engine you would have to de-rate it severely.

[@timhallas4275]

@@keithstudly6071 A NASCAR Stock car engine must produce 800 -1000 hp for up to 3 hours of the most punishing use in any form of racing. The aircraft engines of the 1940s were designed to produce a huge amount of torque. That is why they averaged over 12 liters displacement and operated under 3,500 rpm. Their hp ratings were meaningless. You are comparing apples to oranges. I had a 7.5 liter v8 that ran on 85 octane pump gas, and was able to consistently put out over 500 hp, under the hood of a truck that hauled 50 tons for 100,000 miles before it's first overhaul. With a supercharger this same engine could produce over 900 hp for the same duration.

[@keithstudly6071]

@@timhallas4275 A Pratt-Whitney R-2800C was RATED for 2200 HP but had been tested to 3600 HP for 200 hours of continuous dyno running at 3600 HP. This is the difference between the power an engine can produce and the RATED power of an engine for aviation or marine use. The Packard was RATED for 800 HP for 750 hours continuous load. It likely could have done better for shorter periods of time but that wasn't what the contract the navy gave Packard asked for. They built and tested to meet the requirements of the contract. While your thinking about boat engines consider the load on the crankshaft a boat engine gets when they hit a wave and the prop comes out of the water and runs free for 1 or two seconds and then slams back into the water. Boat engine lower ends see stress that very few applications see.

[@johnshields6852]

McHales navy, I was a kid then and loved that show mainly because of pt boats, the engines sound beautiful, plus JFK was on a pt boat.

[@adamwort7160]

There was one of those engines at pounds shipping Portsmouth in the shed I saw it in 2006

[@jinksomiabodyart3189]

Amazing job. Thanks.

[@robertthegrape2192]

Great engines!

[@craigmcdonald2110]

Great video thanks for sharing

[@oceanmariner]

I was a commercial fisherman. Years earlier an older friend bought a PT right after the war for tuna jig fishing. When he first got the boat he put a few hundred gallons in the tanks and went joy riding with family and friends. In a few hours the engines started missing and then stopping. The Coast Guard towed him back. One of the coasties had been on PTs during the war and told him the engines burned 50 gallons per hour per engine at speed. He pulled the gas engines and put in 3 war surplus Detroit Diesels.

[@ern48]

Nice educational video on Packard V12 engines. I worked on a friends PT boat engines in the 90s. The Packard engines had been replaced with 2) direct drive forward mounted 8v71 Detroits and a single 6-71 with a v-drive in the center, this configuration is the opposite of the description in this video. We ran the boat from NC up to Toronto for a tv movie, "JFK Reckless Youth". This boat was also the Coast Guard boat in the 1991 movie "Sleeping with the Enemy".

[@darrellborland119]

Ward Bond there at the end...fascinating video.

[@rogerclark9285]

From They Were Expendable..

[@marcfriedman7339]

My father worked at Packard machining harmonic balancers for these engines before he went into the Army in WWII.

[@bnnttdenn]

The Packard museum in Warren Ohio has a new never used Packard PT boat engine on display..

[@EricTheOld]

Awesome and informative! I've subscribed. I watched McHale's Navy as a kid in the 60s and in the 70s dreamed about building a fiberglass PT boat with three supercharged Allison's. I still dream of that until I awake to reality😂

[@monsieurcommissaire1628]

I hope you come into an unexpected and ma$$ive windfall and get to build your PT! ⚓Fair winds & following seas!

[@LBG-cf8gu]

thanks for the upload...

[@edwardpate6128]

A great video that I will reference when folks on aviation pages keep referring to this as the Merlin!

[@LesSharp]

Please do!

[@phlodel]

They won't hear any different, either. It was made by Packard and it's a V-12, it's a Merlin.

[@billadams1018]

Wonderful video!

[@johngillon6969]

Video made me happy. I made a few parts for the guys restoring P.T. 658 in portland or. anyone who wants to see this boat is in for a real treat. It is a small museum of regular guys. One of the finest museums you will ever see as there is also a world war two landing craft museum there also. It is a small operation and they have a phone number listed i am sure on their web site. They are justly proud of the boat and all the unbelievable work they have done, but very few folks show up to view the museum,, so if you just call them they will most likely drop everything and open the museum any time you want. seriously i recommend this museum to any body into world war two history, or that has even been a military veteran. Also i enjoyed the film clip about the monkeys of Zamboanga that had no tails. Zamboanga is one of my favorite ports of call.

[@seymourwrasse3321]

the WW1 surplus motors made fine rumrunner boat motors, boat building yards would be building boats for the coast guard, on the other side of the yard they would be building faster boats for rumrunners

[@dukecraig2402]

There were more changes to the 3A-2500 engine to use them in the PT boats then just water cooled headers and a few other things. After the war when he was interviewed the engineer that made the changes to create what eventually became the 4M-2500 engine used in most of the PT boats during the war claimed it was a "clean sheet" design, that isn't exactly true, it was more of an "overlay" design, ie if you draw the crankshaft, pistons, connecting rods and valve's of the 3A-2500 aircraft engine and then designed the rest of the engine around it then you'd be doing an overlay design. The bore, stroke, connecting rod length center of eye to eye and the cylinder spacing center to center are the same between the 3A-2500 aircraft engine and the marine version and that's about the only things that are the same, the blocks, cylinders and heads are completely different castings and even different designs, the cylinder banks are one piece aluminum with steel cylinder sleeves as opposed to the 3A-2500 engine which were individual forged steel cylinders. The changes were extensive and Packard underestimated the amount of work it would take to do it leading to them losing a considerable amount of money creating the marine version. And yes the after-cooler was to add more power, it would have worked in conjunction with the existing inner-cooler, raising boost levels is possible with higher octane fuels but creating that much more boost creates a significant amount more heat in the compressed air (charge air) of the boost, it's not a linear increase in heat as boost is increased there's a curve in the formula, all the aircraft engine's of WW2 (as far as the Allies are concerned) required better charge cooling as boost was increased which was made possible by higher octane levels, the rise in charge temperature is much greater from 25 lbs of boost to 30 lbs than it is from 20 lbs to 25 lbs, as the higher octane levels gave them the ability to raise boost levels they had to design better charge cooling systems (inner and after coolers) to deal with the increased heat, otherwise even though you've increased boost levels you'd have to richen the air/fuel ratio and retard the timing to control detonation (knock) to the point where most of your power increase from the higher boost is canceled out from what you have to do to deal with the higher charge temperatures.

[@LesSharp]

Thanks very much for filling in that detail!

[@dukecraig2402]

@@LesSharp Re-read my post, I just edited it adding some information about the after-cooler added onto the late war engines.

[@williambikash6645]

Could a 4m-2500 be upgraded to a 5m-2500? How much boost pressure did the 4m and 5m develop? Did the octane requirement stay about the same between the 4m and 5m because of the cooler charge temperature on the 5m? I believe the 5m developed 1850 hp.

[@dukecraig2402]

@@williambikash6645 Don't know, could be they added the after-cooler just to be able to run more boost on the same level octane or could be they added it because octane levels increased and they had to add it to take advantage of the higher octane and could run more boost. As far as boost levels they ran on the engines of those PT boats i don't know what they ran, and I'm not sure if they measured it in psi or inches of mercury, American military aircraft in those days used inches of mercury as their measuring standard so I've no reason to believe the PT boats would use any other measuring standard aside from that, but you never know so I can't say one way or the other with 100% certainty, there's several videos on KZbin that give tours of PT boats on display in the US, if during the tour you can see the boost guages when they're in the engine room where the guy who ran the engines sits at the controls one should be able to determine which it is if they show the guages close enough, 30 psi of boost is right around 76 inches of mercury so a good look at the number's on the dial face of the guages should answer that question, if the highest number on the guages is around 35 or 40 it'd be psi but if it's 80 or 90 it'd be inches of mercury, which it probably is since US aircraft used that, the British used psi and the Germans used atmospheres for their's (it's abbreviated as ATTA or something like that). As with the aircraft engine's I'm sure these followed suit when it came to HP increases, different cams and other major components that one would typically associate with increasing HP in cars and motorcycles weren't used to increase HP it was always just a matter of increasing boost, either by way of higher octane and better inner/after coolers, the only change in a major engine component in US aircraft engine's that I'm aware of for the sake of increasing power is the engine for the P47M/N engine when it was increased to 2,800 HP at War Emergency Power (WEP), the static compression ratio of the pistons was raised from 6.5:1 to 6.7:1, but those engines also had an improved turbo and after-cooler's also,, previous to that all the HP increases were done without any changes to internal engine components, just increased octane, better turbos and inner/after coolers. As I explained just raising octane itself doesn't allow you to run higher boost levels simply because without cooling your increased boost intake charge that much more to offset the increased temperature in your it the benefits of increased boost are canceled because of having to retard the timing and richen the air/fuel ratio to keep detonation from occurring. In a highly boosted engine like these detonation can shred one of them in seconds if it's bad enough, I ask a pilot once who ran Pratt&Whitney R2800 engines in a cargo plane in the late 80's if you can hear detonation in one like you can in a car and he said you couldn't, that what makes it so dangerous and is why pilots flying aircraft with high boost engines have a chart inside the cockpit that shows timing and fuel settings for boost levels that must be strictly adhered to, if they get into detonation far enough the engine will sputter and power will drop and they know they have a problem but if it's not at that high of a level they'll be tearing the engine apart and not even know it, that's a big problem in places like over the ocean where you're hundreds of miles from land, I hope you're a good swimmer if you don't pay attention to those charts. It's getting increasingly rare these days with cars and motorcycle's due to the advancements in the aluminum pistons are made of but back in the day I had more than one engine brought to me for rebuilding that had holes blown through the tops of the pistons from detonation, mostly these days I'll see damage done to the tops of pistons from it that looks like someone took the ball end of a ball peen hammer and beat on the top of the pistons, but between modern engines having hypereuticic pistons stock from the factory and forged aftermarket pistons in modified engine's I haven't seen a hole blow in a piston from detonation in some years now, but I still occasionally see one on an air cooled motorcycle engine that's got a hole melted through one from the engine developing a massive vacuum leak and the operator not understanding what's going on.

[@williambikash6645]

@@dukecraig2402 Thanks for going into so much detail. I help maintain a friend's 20 yo triple engine Fountain speed boat with stock and original 575 hp supercharged 502ci Mercruiser engines. These engines have Roots style blowers with no coolers and develop about 4 lbs boost. They have 2 GM style throttle body injections per engine and block mounted knock sensors. They call for 92 pump octane and we stay out of boost when we use 89 octane in a pinch. The current 502 Mercruiser versions are 600 and 700hp and run on 87 and 89 octane. They use axial flow superchargers without coolers and have modern FI systems and sophisticated electronics ignition systems. The 575s are original and have not been rebuilt. The center engine has never had the valve covers off! They have over 700 hrs and the boat still does 90mph. Factory rated when new was 93 mph which I can't verify. Chevrolet recently released a 632 ci BBC crate engine that developes over 1000 hp na. It has a new design aluminum cylinder heads with 12.5 to 1 cr and runs on street gasoline, 93 octane, I'm amazed!

[@Dulcimerea]

In the 70s, I went to a truck and tractor pull in Kansas City, and one of the tractors had a submarine engine on it, wow did it roar and pull.

[@fdhicks69]

Doubt it. Submarines used FM 38 8-1/8 engines. They are 9.3 meters long and weigh 38 tons in 12 cylinder configuration. Each cylinder displaces 17 liters.

[@claiborneeastjr4129]

Really fascinating Packard engines. I didn't realize the two outboard engines had V-Drives; whereas the center engine had direct drive. I'm surprised they could be even run on 87 octane gas, which I'm sure was leaded. Also the shaft-drives to the overhead cams are unique. Also, I'm surprised the exposed valve trains of the old Liberty engines didn't gunk up with dirt and debris. I'd guess that a PT boat at WOT consumed at least 150 GPH, maybe more. They were impressive. Great video and quite interesting.

[@JosephStately]

I believe the fuel they used was 100 octane aviation fuel

[@walthammond6816]

You are correct.

[@wilburfinnigan2142]

The shaft drive to the overhead cam was NOT unique as the Allison and RR used a similiar system !!!

[@brianwilcox3478]

Yes try 500GPH at WOT Thirsty engines

[@garysmith2188]

About five years ago I visited The National World War II Museum in New Orleans, Louisiana. They were restoring a PT boat and I know it was equipped with three Packard engines, all right-hand drive!

[@alleyoop1234]

I know a guy that is an antique boat restorer that has one of these Packard marine engines. Next time I'm there I will ask more about it!

[@kimmer6]

In the 1970's there was a complete Packard 2500 PT boat engine on a stand inside the Mechanical Engineering Building at Cal Poly San Luis Obispo. I wonder if it is still there.

[@jimclarke1108]

Amazing information

[@Aceman597]

My grandfather ran a Crash Boat ( rare) and was faster than the PT. It was PT boat they took off the torpedoes and third center engine . It ran twins . His boat did S/R for pilots and patrol. Even hauled an army jeep on it speeding around the Philippines.

[@never-stock-rc2968]

This stuff tickles my fancy way cool I'm 43 and I just love this knowledge!!!!

[@dobermanpac1064]

Great story. The Pacific War in my mind at sea was won on the backs on the Enterprise and the Pt’s.

[@LesSharp]

Submarines

[@dobermanpac1064]

@@LesSharp Them too.

[@chrisabraham8793]

The Liberty 12 was also used in British tanks during WW2, the early A13 cruiser tank and Crusader tank.

[@wilburfinnigan2142]

Yes they were until the UK got their meteor engines up and running!!!

[@billmerkle2677]

I sure wish more of these great boats were around. Would enjoy piloting one of these which are over twice as long as our current Trojan (1980).

[@bruceramseyramsey2605]

Nice job... thanks

[@bogey361]

Great vid Les.

[@POBulkhead]

"I love that kind of talk."

[@nickdanger3802]

71.5ft British Power Boat MkV MGB 3x Packard M-2500 petrol engines Fairmile D MGB 4x Packard M-2500 petrol engines Spitfires of the Sea Motor Gun Boats page

[@LesSharp]

Thanks for that! The Huckins PT also had four Packards and swilled gas like there was no tomorrow.

[@nickdanger3802]

@@LesSharp No trouble

[@feedingravens]

Nevertheless, Packard took over the building of Rolls-Royce Merlin engines for e.g. the P-51 Mustang (as the Allisons had no performance at height). The overall design was good - but the Merlins were more or less hand-built, each one a unique example, and often you could not change parts without modifying them to the particular engine. So Packard reverse-engineered the Merlin, and converted it into metric, and made it suitable for mass production. So they also achieved that parts would fit directly, greatly reducing maintenance costs and time.

[@markhorton3994]

I have a little semi- inside information. Many of the Rolls-Royce/Packard Merlin aircraft engines were built by the GM. Chevrolet engine plant in Flint. My grandfather was a machinist turned inspector. When the Packard inspectors visited they were astonished by how fast and accurate Chevy was. They got better piston - cylinder interchabilityvthan Packard could. Even though Chevrolet was a cheep production line car and Packard a hand made luxury car. My grandfather told them that that was why. Packard could afford to hand fit each piston and cylinder so there was very little interchangability. Chevrolet had less margin and couldn't afford to hand fit that many cylinders. The machininy had to be much more precise to keep down costs. There was a secret assembly line hidden between two other lines at the Flint plant. No one not working on it or supervising it knew what it made. Rumer said Norden bomb sights but my Grandfather never knew and either will I.

[@geoffreypiltz271]

These engines also powered British Fairmile D MTB's (Motor Torpedo Boats) and MGB's (Motor Gun Boats).

[@wilburfinnigan2142]

Absolutely !!! Via lend lease !!

[@percyprune7548]

Most beautiful vessel ever built. Only an irretrievable deteriorated hull in a Norwegian fjord as the last survivor of all the D's - Dogboats - but there is a Fairmile B awaiting restoration at Hartlepool.

[@tracksofnyc]

Once upon a time, when Pride ran through the blood of all Americans.

[@ianbutler1983]

You misgendered me!!!!! lol.

[@sprezzatura8755]

No God, no unity, no future.

[@waynetaylor8082]

Not only pride, but a belief in the common good. Where our differences don't make us enemies. PEACE ✌️

[@johnschoonmaker-tm3ll]

From a time when schools taught pride and love of America.

[@kevinhanson8142]

Thanks! I’m going to Portland in a few weeks, going to look for PT658!

[@LesSharp]

Jealous. Try to run into @Jerry Gilmartin. He knows more about these engines than just about anyone!

[@kevinhanson8142]

I will! We’re going tomorrow or Monday, need to call them but we’re in Ptown! Hopefully we can take pictures!

[@erroneous6947]

I think the pt boat idea is underrated. Iran still uses the concept. You could argue they do it out of cost. In this day and age give it some kind of drone and anti drone capability. I think it could have a place in coastal/harbor defense.

[@danieltorrens4954]

When I was a young boy in the late 60s early 70s they had old PT boats in NJ that they would give you rides on, very fast and you would be drenched after you were done!

[@markekberg8371]

Considered an amazing feat. While I agree somewhat, a 750 hrs life span with a very high cost does not seem very good.

[@billt6116]

36 cylinders of whooping ass! In their days they would pass anything on the sea... Except a fueling stop. And that was for extremely flammable, high octane aircraft fuel.

[@joewoodchuck3824]

Very interesting.

[@gmac8852]

My neighbor says he served on PT 73 during the war to end all wars.

[@JesseWright68]

World War One?

[@gmac8852]

@@JesseWright68 yeah he's crazy 🤪

[@bferguson9277]

One of these engines is on display at America's Packard Museum in Dayton, Ohio.

[@babaganoush6106]

This is great thanks. Very clear. I also understood the pt boat and British mtb to be powered by merlin engines. The merlin was used as a tank engine (called Meteor used in comet, centurion etc) and in trucks as well as cut down to a V8 (Meteorite). Oh and yes it was used aircraft lol. Rover eventually swapped with Rolls-Royce its jet engine production for the Meteor.

[@wilburfinnigan2142]

Baba Ganoush Many of the British MTB's also used the Packard M2500 lend leased from the USA. the M2500 was 50% Larger than a merlin which were needed for aircraft !!!! Just a FYI

[@boatdetective]

The British MTBs were 72' Vosper designs. The vast majority were built in the US- some in Canada. They were powered by the same Packard 3M-2500s mentioned here.

[@percyprune7548]

Also the Fairmiles, the Fairmile D or Dogboat was 115' long.

[@tonyclough9844]

The meteor is an engine that dosnt meet areo standards and were downgraded from aircraft use.

[@georgesheffield1580]

These engines were also used by the Brits in their PT boats . They were also used in the air sea rescue launches .

[@andrewwmacfadyen6958]

They gave less problems than the Merlins in British MTB and MGB the Merlin didn't get on with salt water, post war as the Meteor and V8 Meteorite this was less of an issue they even made a diesel version

[@wilburfinnigan2142]

Yes they did as the brits received several thousands of the Packard M2500 and the quality of those engines is what brought RR engineers to Packard for the Merlins !! !

[@wilburfinnigan2142]

@@andrewwmacfadyen6958 And they were a lot mor powerful !!!

[@m1t2a1]

McHale's Navy taught me everything I need to know, or so I thought.

[@Trump985]

Did you say they had to be rebuilt at 750 hours? I can’t wrap my head around that! That’s only a month of running! I thought our Cummins diesels were bad requiring overhauls around 25,000 hours! 750 hours that’s just insane. It’s a miracle we won the war with junk like these engines in our boats and planes.

[@raymondj8768]

That was a cool movie !!!

[@jrsgarage7623]

A friends dad has one of these engines in a pulling tractor. You can feel it in your chest when it's pulling at full power.

[@bigredc222]

A lot of tractor pull tractors had Packard motors in them in the 80s. They were always my favorite.

[@jrsgarage7623]

@@bigredc222 same guy had one with the Allison v12 and one with 3 5.3l in a row

[@bigredc222]

@@jrsgarage7623 Now that I think about it, the tractors I saw had Allison engines, not Packard.

[@jrsgarage7623]

@@bigredc222 the Allison had a Holley four barrel that was huge

[@jrsgarage7623]

@@bigredc222 I think the Allison came outta airplanes and the Packard was the pt boat motors

[@daviddavid5880]

Very cool

[@331SVTCobra]

Patrol Torpedo boats were not actually "lightning fast". Their main tactic was to slowly creep around at night. A bow wake and churning propellers would be visible even on a very dark night. On the few occasions when a PT boat approached a major surface combatant they would creep forward slowly, being within a mile would be considered very close, they would fire their torpedo (praying to God that grease in the tube didn't flash), and then slowly creep away before the torpedoes hit which was almost never. Pretty quickly the role of the PT boat changed from torpedoing warships to patrolling for Japanese supplies that were pushed overboard and expected to drift to Japanese-controlled beaches. This along with intercepting heavily gunned Japanese light craft which would transport a handful of troops or supplies. Torpedo launchers were landed and additional gunnery was installed. With the hull typically in the water, speed rarely needed, and maintenance facilities non-existent, their hulls quickly picked up beards of moss. 100 octane gas during wartime was also not guaranteed to be available. Bottom line, a brand new PT boat without armament could maybe do 40kt, but put a crew on it, configure it for gun battles with maybe two torpedoes "just in case", give it questionable gas and a moss beard, and even if it could do 30kt, if it were in a combat situation it would be creeping along at night.

[@ericcsuf]

Any significance to the Morse code "HIstory on Location" in the beginning of this video? Didn't hear it on any of your other videos. Excellent video, BTW.

[@LesSharp]

I use it in lieu of the titles. I found that people tend to skip forward when they see my channel 'teasers', expecting 20s of fluff unrelated to topic. I figure only those who are interested would be bothered to decode it and most might not notice. So, kudos to you! Most of my war history videos are based around the idea that I can visit the actual locations and film current day reality there, which is usually the case. This time not, but it's the theme of the channel.

[@ShakespeareCafe]

PT-109 movie was filmed in the Florida Keyes

[@bearshield7138]

I am having a grand time watching these. Do you have any ideas as to where to find ELCO PT Boat blueprints? I would like to hang them in my shop.

[@LesSharp]

I don't, but there are Facebook groups for PT boat modelers. I bet they would have a line on drawings.

[@stevemcdonald4885]

The Morse code at the beginning says history on location.