SS MT Washington II

[Pepper]

Originally Posted by carguy

...
Someone with access to the Mount should ask the Captain what speed the Mount is cruising at by GPS.

WeirsBeachBoater could probably provide any data you'd like with regard to speed, engine size, horsepower, etc.

[Pepper]

Here's another photo for perspective on the size of those engines ...

[Resident 2B]

I believe the engines are 6,500 hp each for a total of 13,000 hp. 615 hp or 650 hp each would not do much to move the Mount.

As far as top speed, remember this is a full displacement vessel so the length of the ship determines the top speed as long as the hp is adequate. I doubt it could get out of the hole and up on plane even with the 13,000 hp.

Their web site appears to be down at present, but I think my memory is somewhat accurate.

R2B

[GWC...]

Originally Posted by Resident 2B

I believe the engines are 6,500 hp each for a total of 13,000 hp. 615 hp or 650 hp each would not do much to move the Mount.

R2B

In a word: Torque

In two words: Big Pistons

In two more words: Big Cylinders

In three words: Lots of Torque

In the animal kingdom, engine wise, you're thinking mouse and you need to think elephant - moves slow but moves alot.

[Resident 2B]

GWC,

Assuming the 700 ton figure for the Mount Washington's displacement is correct, and I feel it is close, 1,300 hp is not going to move a 1,400,000 pound vessel anywhere near 15 knots, let alone provide adequate reverse thrust when docking.

I am not trying to be argumentative, it is just physically impossible.

I understand torque. It is often measured with a distance and a force, such as foot-pounds. You still need the force component to develop high torque. Energy cannot be created or destroyed! I believe that is still a principle of science.

Let's wait until the web site comes back and see what they claim for hp.

Best regards,

R2B

[GWC...]

Originally Posted by Resident 2B

GWC,

I am not trying to be argumentative, it is just physically impossible.

Let's wait until the web site comes back and see what they claim for hp.

Best regards,

R2B

Okay, Don (Webmaster), I'm being good, even though I know the answer and do not need the data from the website and you're thinking, "GWC... you're trying, very trying."

The upside, this website is indeed informative and educational.

[carguy]

Resident 2B:

The Mount displaces approximately 700 tons of water (That is how they weigh ships, the amount in tons of the water displaced by the hull in the water). The diesel engines are 615 HP each for a total of 1230 HP. There are many other factors that determine the speed beside horsepower and displacement weight.

[Resident 2B]

Carguy,

I still think 1300 hp is not enough to do the job. I could be wrong, but to me it does not add up. From what I have read, the engines taken from the vessel in the 1940's were only 750 hp each, so you folks may be right. I am sure someone from the Mount Washington can give us the facts.

Regarding weight, the amount of water displaced is equal to the weight of the vessel. That is why it floats. If it weighted more than the water it could displace, it would sink. A vessel will displace an amount of water equal to it's weight and the waterline is established at that point.

If it displaces 700 tons of water and floats, it weighs 700 tons or 1.4 million pounds.

R2B

[carguy]

Resident 2B:

The diesel submarine that I served on in the late 1960's had three 1600 HP Faibanks Morse opposed piston diesel motors, and they looked a lot bigger than the two engines in the Mount's engine room. I stand by my 1230 or closely thereabouts horsepower figure, definately not 13,000 HP.

[Resident 2B]

I just dug out my special edition of the Weirs Times on the Mount and it states "two 615 hp Enterprise diesels".

I will always admit it when I am wrong, and I was! I am still very surprised about the low power.

R2B

[mcdude]

[Mee-n-Mac]

As was stated earlier:

Originally Posted by GWC

In a word: Torque

I'd say torque for acceleration, power for speed.

Torque is a force and Newton wasn't kidding when he said F=MA or turning it around, acceleration = force (or torque)/ mass. I don't know the torque #'s for the Mount (and what, if any, gear ratio is used) but they must be large to move that ship. Power is the rate at which work is being done and HP = torque * RPM * conversion factor. The conversion factor is a number that scales ft-lbs & rpm into HP, or newton-meters & rad/sec into watts, or whatever, depending on the units you're using. So relatively low HP can still move big masses (high torque) but the RPMs will be low. The acceleration of the Mount is also pretty slow when compared to a typical boat. Even a low torque engine could theoretically move the Mount but you might only gain 1 mph every hour.

As for theoretical top speed, I recall the approximation that hull speed (knots) is 1.33 * square root (waterline length). I'm not sure what the LWL is for the Mount, mebbe 200 ft or so ? So that's about 19 knots. With a lot more HP you can go (slightly) faster and perhaps the Mount is more "draggy" that typical so it might top out lower than predicted. Could also be that the prop pitch and gearing is such that redline is hit before max "hull speed". I dunno. Anyone know what the redline on the Mount is ?

For more that I care to know, you can look here. Using their formulas I get a delivered power requirement of 628 HP for the Mount to do 18.8 knots. Given the losses in the prop/water coupling and then in the gearbox/transmission, the HP needed at the engine is at least 20% higher. So, contrary to expectation, the Mount's twin ~650 HP engines appear to adequate (given the ballpark nature of my calculations) to overcome the water's friction (drag). Kinda surprised me too. The residual HP (1300-[628+20%]) can then be used to fight the resistance that comes from making the wake(s). I leave it to the reader to calculate how much HP is needed to overcome wake resistance (and yes, there will be a quiz in the AM).

ps - During one of cruises I asked one the Mount's crew what her top speed was and the answer was about 14 knots or a little over 15 mph. Not sure what typical cruise speed is.

[skprbob]

A nice thread - to confirm some of the items:

The Mount's engines are 1946 Enterprise, 615 HP each. 12 in bore, 15 in stroke. They top out at 450 rpm, but are normally run at a 400 rpm maximum. At that speed, she makes almost 15 mph with an average load. At so-called 2/3 throttle, or 300 rpm, she makes just over 10 mph.

The drive train is direct drive - no transmissions - so "neutral" is actually shut down. To reverse, the engines are restarted with the opposite rotation. Incidentally, she got new props two years ago. The old ones were originally 60 in diameter, but had actually worn down over the years to 55 in. The new ones are back to 60 in with much improved efficiency.

Also - great pictures! And yes, the man in the engine room is Darryl "Doc" Watson - now retired.

[carguy]

SKPRBOB:

Did the Mount ever run faster than 15 MPH?

I recall that she did around 20 MPH back in the late 1950's, long before the 25 foot addition and additional superstructure pieces.

[Mee-n-Mac]

Originally Posted by carguy

SKPRBOB:

Did the Mount ever run faster than 15 MPH?

I recall that she did around 20 MPH back in the late 1950's, long before the 25 foot addition and additional superstructure pieces.

Here's a thought. I can't say anything about her top speed then vs now but I will say the wake size sure seems smaller now vs then. If I'm correct in this recollection then I'll further speculate that the top speed now is the same (? perhaps higher ?) as back then. Here's my thinking ... keeping all other things the same, whatever increase in drag she gained due to the added wetted area was offset by a reduction in drag due less energy lost in making a wake. Where did these competing interests balance out ? Got me, perhaps some secret sources can tell us.

[carguy]

Originally Posted by Mee-n-Mac

Here's a thought. I can't say anything about her top speed then vs now but I will say the wake size sure seems smaller now vs then. If I'm correct in this recollection then I'll further speculate that the top speed now is the same (? perhaps higher ?) as back then. Here's my thinking ... keeping all other things the same, whatever increase in drag she gained due to the added wetted area was offset by a reduction in drag due less energy lost in making a wake. Where did these competing interests balance out ? Got me, perhaps some secret sources can tell us.

Yes, the Mount's wake does seem lower in height than it did when I was a kid. Back in the late 1950's as a boy at Lake Shore Park, one of the highlights of the day on the waterfront was riding the wakes of both the Mount Washington and the Sophie C., in our inner tubes, as the wakes crashed against the concrete wall by the Big Pier. The Mount's wake was wider, but the Sophie C.'s wake was higher. Back in those days, prior to being the mail boat, the Sophie C. almost had the same route as the Mount. The Mount had a four hour trip that included the ports of the Weirs, Center Harbor, Wolfeboro, Alton Bay, and back to the Weirs. The Mount made this run twice a day. The Mount passed Lake Shore Park at 12:45 PM and 5:45 PM. You could set your watch by it passing the Big Pier.

[skprbob]

I don't know for sure, but I strongly suspect that the Mount went faster than 15 mph back in the 50's since her engines were usually run up around the 450 rpm level. Nowadays, although they're still capable of 450, 405 rpm is the normal max. Plus the routes are now shorter than they were then.
Those of you who remember a larger wake back then are right. Her wake got smaller when she was lengthened. She got longer, but not wider. Also, the new section actually increased buoyancy, requiring several tons of concrete ballast to bring her back down to the proper water line.

[carguy]

Originally Posted by skprbob

I don't know for sure, but I strongly suspect that the Mount went faster than 15 mph back in the 50's since her engines were usually run up around the 450 rpm level. Nowadays, although they're still capable of 450, 405 rpm is the normal max. Plus the routes are now shorter than they were then.
Those of you who remember a larger wake back then are right. Her wake got smaller when she was lengthened. She got longer, but not wider. Also, the new section actually increased buoyancy, requiring several tons of concrete ballast to bring her back down to the proper water line.

Skprbob:

You are very knowledgeable about the Mount. You wouldn't be a crew member would you?

I was hoping to get some scenes dated from my old video on the Lakes Region. I was thinking that you might know who the crew member is in the attached photo, and when he served on the Mount. I am guessing the early 1950's.

[gtxrider]

Originally Posted by Mee-n-Mac

Here's a thought. I can't say anything about her top speed then vs now but I will say the wake size sure seems smaller now vs then. If I'm correct in this recollection then I'll further speculate that the top speed now is the same (? perhaps higher ?) as back then. Here's my thinking ... keeping all other things the same, whatever increase in drag she gained due to the added wetted area was offset by a reduction in drag due less energy lost in making a wake. Where did these competing interests balance out ? Got me, perhaps some secret sources can tell us.

I remember the wake being bigger but than I was smaller. We used to try to get our skiing in before the morning run down Alton Bay. It seemed after the Mount came by the water stayed rough until much later in the day. Back in those days she made 2 trips every day. I think the morning run came by before 11:00AM

I miss the toot as she passes Sandy Point

[Weirs guy]

Originally Posted by skprbob

Incidentally, she got new props two years ago. The old ones were originally 60 in diameter, but had actually worn down over the years to 55 in. The new ones are back to 60 in with much improved efficiency.

Assuming her props were original to the 1940 refit (or even younger) thats around 1" off the diameter every decade?!?

[skprbob]

carguy - Yes, I'm a pilot and engineer, seasonal/fulltime since 1994.

Capt. Bob - The screen name comes from the years when I skippered the Sophie C as a seasonal crew member. Best summer job for a schoolteacher that I can think of!

[Captain Bob]

Originally Posted by skprbob

Capt. Bob - The screen name comes from the years when I skippered the Sophie C as a seasonal crew member. Best summer job for a schoolteacher that I can think of!

Skprbob,

I realize I should know this, but is the Sophie C still in operation? As a kid 50's/60'5, it was always the Mount, The Sophie C, and the Doris E, plus some lake speed boats like the Miss Winnepesaukee - but the only one I was ever on (5-6 times) was the Mount! I thought teachers were lucky that they got the summer "off" - seems like your summer employment was an even better deal!

Captain Bob

[WeirsBeachBoater]

Still in operation. Celebrating over 60yrs!!! Delivers the mail June 15th thru the second Saturday in Sept. Great Fun, getting to interact with the islanders. Especially 3 mile

[skprbob]

Captain Bob - Sophie is very much in operation, though done for this season. Her mail delivery runs from June 15 through the Saturday after Labor Day and leaves Weirs Beach at 11:00 AM and 2:00 PM for two hour trips. That was a job I enjoyed very much and I try to get back to her a few times a season, mostly in the early and late season when her current skipper must return to his classroom! Doris is also still around, but also done for this season.

gtxrider - you can still catch the Mount in Alton Bay on Sundays and Thursdays through the end of October, around 11:15 and 2:00 (those times VERY approximate).

[carguy]

McDude:

Thanks for the photo and your input.

Resident 2B:

I also pulled out one of my special editions of the Weirs Times yesterday. I forgot that I had a couple of these, for they are over 10 years old. I got most of my information from Blackstone's Farewell to thee Old MT. WASHINGTON. You just had too many zeros in your horsepower rating. You would think that they would have had bigger engines, but possibly that old iron hull couldn't take the stress. Back in the 1950's I think I recall that the Mount might have been faster, let's say 20 MPH top speed. Adding a 25' extension, more equipment, and more superstructure, increased the weight of the Mount quite a bit, thus slowing it's top end speed down to around 15 MPH. Only the operators of the Mount could substantiate this theory.

[WeirsBeachBoater]

But in a nutshell.
The engines are inline 8 cyl Enterprise Diesels 615hp each
Direct Reversing, Direct Drive, No transmissions, therefore no powerloss in transmission.
The props are 60 inch in Diameter

The top speed on the GPS is approx 14.8mph
Night cruises are typically around 9.9 mph

She slides through the water fairly well for her size.

The gentleman in that picture by the starboard engine is Doc Watson former Chief Engineer for Winni Flagship.

[GWC...]

Something to pass the time on a rainy day...

Mount history:
http://www.lwhs.us/steam-mtwashhistory.htm

A website about Enterprise Diesel Engines:
http://www.oldtacomamarine.com/enterprisemore.html
Notice the RPM of the listed engines, and their Bore and Stroke – big and slow, like an elephant.

Pictures of an eight cylinder from two different angle.

[Weirs guy]

OK WeirsBeachBoater, the only way to settle this is we all need to take a little spin in her and see what she's got. Lets say Monday afternoon?

The old girl generates enough torque that when shes put into full reverse when pulling into the Weirs docks she'll shake the windows in my house from about 1/4 of a mile away. Thats a lot of water displacement.

[WeirsBeachBoater]

The model engines that are in the mount are 12X15 Bore-Stroke

[Mee-n-Mac]

Anyone notice the cylinder counts on some of the other Enterprise diesel engines ? 7 and 9, how very odd. Now maybe WBB's secret source can tell us the pitch of the screws ....

[WeirsBeachBoater]

The engineers will send their goons after me if i tell all the Mounts secrets.

[mcdude]

Here she is seen at the Weirs shortly after her launching.

[carguy]

McDude:

Nice photo of the Mount in 1940. I have never seen this particular photo before in any of Heald's books or Blackstone's books on the Mount.