190 MONTAUK with 115-HP is Under-power

Optimizing the performance of Boston Whaler boats
tlsch377
Posts: 5
Joined: Fri Aug 18, 2017 2:33 pm

190 MONTAUK with 115-HP is Under-power

Postby tlsch377 » Thu Mar 29, 2018 8:00 pm

[New Topic introduced into a discussion on how to make a repair; this topic has been separated and is now its own thread.]

A 190 Montauk with 115-HP is under-powered. A 115-HP [on a used 190 MONTAUK] may have been a replacement engine, I can't imagine a dealer selling [a 190 MONTAUK] with such a small engine. I'd try to buy it at a price that allowed for a re-power with 150 to 175-HP.

Jefecinco
Posts: 809
Joined: Fri Oct 09, 2015 6:35 pm
Location: Gulf Shores, AL

Re: 190 MONTAUK with 115-HP is Under-power

Postby Jefecinco » Fri Mar 30, 2018 7:19 am

Many 190 Montauk boats were sold with 115-HP engines. Early 190 Montauk hulls were rated for 135-HP maximum. Our 190 has a 135-HP engine and is a very good performer. I believe the current 190 Montauk is rated for a maximum of 150-HP.

A 115-HP engine will provide very adequate performance on a 190 Montauk.
Butch

jimh
Posts: 5445
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby jimh » Fri Mar 30, 2018 7:59 am

BUTCH--thanks for your first-hand report of owning a 190 MONTAUK with a 115-HP engine and its performance.

Any seller of any 190 MONTAUK with 115-HP (or any boat with a working engine only a few years old) will not price the boat as if the engine has no value--which is the price a buyer who thinks the present engine must be removed and immediately replaced will have to offer. The seller won't accommodate an offer like that because the present engine actually does have value. The engine has value even if the hull is rated for 20-HP more. If a buyer wants an engine with more horsepower, they better look at another boat rather than try to buy one with a 115-HP engine "at a price that allowed for re-power." The cost of any re-power with a new 150-HP or 175-HP engine is going to be a significant portion of any used boat's total value. A buyer will be more favored buying a recent model boat with an engine he likes as-is.

tlsch377
Posts: 5
Joined: Fri Aug 18, 2017 2:33 pm

Re: 190 MONTAUK with 115-HP is Under-power

Postby tlsch377 » Thu Apr 19, 2018 9:25 pm

The [advice to a buyer of a 190 MONTAUK with 115-HP] is walk away, unless you want to get into the used engine sales business. The [190 MONTAUK] is a very good hull, a good boat, but the [115-HP] engine is small for the weight, beam, and length.

I am not in a position to challenge the theory that every engine has a value--they do--but this engine is small for the hull. [A buyer should] walk away.

jimh
Posts: 5445
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby jimh » Fri Apr 20, 2018 8:26 am

If a 190 MONTAUK with 115-HP is unsuitable for any buyer to consider, exactly how did Boston Whaler manage to sell so many 190 MONTAUK boats with 115-HP engines as new boats?

If all buyers followed the advice given, Boston Whaler would have never sold any 190 MONTAUK boats with 115-HP engines, and there would be none available as used boats.

ferdinando
Posts: 76
Joined: Thu Oct 22, 2015 3:51 pm

Re: 190 MONTAUK with 115-HP is Under-power

Postby ferdinando » Sun Apr 22, 2018 10:52 pm

Back in 2008 I purchased a brand new 190 Montauk [with 115-HP] and quite frankly I almost cried the first time I took her out. Mind you I was 56-years-old and not a speed freak or skier. I only wanted to cruise and occasionally fish. I found this boat to be quite under-powered for my tastes. I sold that 115-HP engine in less then a year and purchased a new E-TEC 150--and the 190 MONTAUK turned into a totally different boat. And all was well once again! Fred

macfam
Posts: 129
Joined: Fri Oct 16, 2015 9:24 pm

Re: 190 MONTAUK with 115-HP is Under-power

Postby macfam » Wed Apr 25, 2018 4:33 pm

Am I missing something?
I don’t recall ever hearing 170 Montauk with Mercury 90 FourStroke was underpowered. See the stats below.

Mercury 90 FourStroke Standard
https://bostonwhaler-8c1e.kxcdn.com/wp-content/uploads/2016/08/Chart-170-montauk-1-1-e1474301205940.png

However, here we are discussing how the 190 with the 115 Command Thrust is woefully underpowered. See the stats below.
Mercury 115 FourStroke Command Thrust
https://bostonwhaler-8c1e.kxcdn.com/wp-content/uploads/2016/08/Chart-190-montauk-1-1-e1474319049419.png

If you compare these stats, they are almost identical. In fact, the 190/115 combo has a slightly higher top end.

jimh
Posts: 5445
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby jimh » Wed Apr 25, 2018 7:52 pm

A simple but very reasonable analysis can be made by comparing the weight-to-horsepower ratio of the two models. The less weight for each horsepower, the better performance to be expected. I use the weight reported in the factory test data as the weight. This should be a good comparison because the two boats have very similar hull forms. And I am using the legacy hulls, not the just-introduced 2018 models.

170 MONTAUK
HP = 90
LBS = 2089
RATIO = 23.1-LBS/HP

190 MONTAUK
HP = 115
LBS = 2960
RATIO = 25.7-LBS/HP

The 170 MONTAUK has a better ratio by 2.6-lbs/HP.

In order for the 190 MONTAUK to have the same ratio as the 170 MONTAUK, it would have to have 128-HP. The 190 MONTAUK looks a bit under-powered compared to the 170 MONTAUK. But this is just a conjectural analysis; there is no real-world data to confirm this conclusion.

There is another element that might also be considered: the 190 has more beam. This means that when the hull is on plane it can generate more lift because there will be a wider hull in left in the water. This suggests it can be driven on plane with less horsepower. We can test and verifty this by looking at the top speeds. Again, I use the performance data from the factory performance reports:

170 MONTAUK = 40.9
190 MONTAUK = 42-MPH

This comparison tells a different story: the 190 is faster than the 170. Now which model is under-powered?

Let's compare time to get on plane:

170 MONTAUK = 4.5-seconds
190 MONTAUK = 4.6-seconds

The variation of 0.1-seconds is probably well within the measurement error range. It's a draw.

We have three analysis: one theoretical, two based on actual test outcomes.

One possible corollary: because the 190 MONTAUK is a larger boat, in actual use it ends up with more people, more gear, and more weight added--because it has more room for all that stuff. Now when the boat is actually used, it has more added weight that the typical 170 MONTAUK will have added to its base weight, because the 170 doesn't have room for the extra people and gear. So the weight-to-horsepower climbs even higher on the 190, reducing performance.

A second corollary: because the 190 MONTAUK is a larger boat, it is used in bigger water, with bigger seas under rougher conditions. The 190 has to run in bigger waves, against bigger seas, into higher winds than the 170 MONTAUK which stays home when the weather is marginal. In these tougher conditions the 190 begins to feel under-powered. Since the 170 MONTAUK does not operate in such adverse conditions, it does not feel underpowered.

User avatar
Dutchman
Posts: 604
Joined: Wed Oct 14, 2015 7:48 am
Location: Kalamazoo, MI (South Haven)
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby Dutchman » Thu Apr 26, 2018 10:43 am

Jim I like your corollaries which speak more to real life and what would be encountered.

Due to the great construction of these boats, I find that many of the Montauk-three-digit-models of the past 20 years or so are or were under-powered.

I have test driven a 2014 170 and a 2014 190 with engines as mentioned here, and with almost full load of crew (five on the 170 and six on the 190) and no gear, I found them to be sluggish as is my 150 (with four crew). They are still great boats and meet what they were built for, but I think under-powered.

macfam--your stats do not show the 190 with 115 to be faster as the speed of the 170/90 at the same RPM shows more. At 5,500 the 170 is faster.

You stats only show 5,750-RPM for the 90-HP and it shows 6,000-RPM for the 115-HP, I don't know propeller pitches for either model but the 250-RPM difference will most likely make up the top speed difference shown in your stats.
Last edited by Dutchman on Tue May 01, 2018 9:39 am, edited 1 time in total.
EJO
"Clumsy Cleat"look up what it means
50th edition 2008 Montauk 150, w/60HP Mercury Bigfoot

jimh
Posts: 5445
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby jimh » Fri Apr 27, 2018 10:58 am

DUTCH--if a buyer chooses a 190 MONTAUK and plans to ALWAYS have six people aboard, then maybe the buyer should be encouraged to get the larger engine option. It is no secret that the base model of any product is usually the cheapest model because it omits all the desirable options.

I can buy a Chevy "work truck" for $23,000, but if I check all the option boxes I can make that same chassis cost $60,000. You just get what you pay for.

If a guy wants a 190 MONTAUK for he and wife to go for a boat ride, I think the 115-HP is going to be fine. Who needs to go faster than 42-MPH?

If a guy wants a 190 MONTAUK to haul around 2,000-lbs of gear in heavy seas, maybe he wants a bigger engine.

User avatar
Dutchman
Posts: 604
Joined: Wed Oct 14, 2015 7:48 am
Location: Kalamazoo, MI (South Haven)
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby Dutchman » Tue May 01, 2018 10:00 am

Jim makes a g good point: why would you want to go over 40 mph in a boat?

But why don't you see two-door work trucks? (I know [the reason you don't see them is due to] taxation and miles-per-gallon.)

More and you see more four-door extended-cab trucks. [The reason is] [a four-door extended cab truck] can move the extra people if you want to. [The truck] still will have the power to handle more and perform the same--even though most pick-up trucks have less than two people in then 99.5% of the time.

The same with the Whaler: most of the time two or three people or less are onboard, but [the boat is] capable of more people. Therefore the powerplant should be set up to handle the extra load.

The extra load in our smaller boats [has] more influenced [on performance] than in a work truck. The Whaler boats cost a lot more ,too.
EJO
"Clumsy Cleat"look up what it means
50th edition 2008 Montauk 150, w/60HP Mercury Bigfoot

jimh
Posts: 5445
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby jimh » Tue May 01, 2018 2:47 pm

DUTCH--your analogy is flawed. I demonstrate the flaw:

--when you buy a truck you get a choice of engines;
--then you buy a 190 MONTAUK you get choice of engines;
--when trucks have larger more powerful engines, their ability to accelerate under heavy load increases;
--when a 190 MONTAUK has a larger more powerful engine, its ability to accelerate under heaver load increases

I cannot see anything about the analogy that is different between trucks and boats. If you want to have better acceleration at maximum loads, buy the option for a more powerful engine. It works in boats and trucks alike.

The effect of weight on acceleration in truck and boats is the same when the two are in similar circumstances. For a wheeled vehicle on a paved road, the equivalent circumstance to a boat in the water on plane will be for the wheel vehicle on a paved road to be travelling uphill on a substantial grade.

If you want to compare power needed for acceleration when a wheeled vehicle is on a paved road that is level, compare to a boat when in displacement mode. Only very modest horsepower, perhaps less than 5-HP, will accelerate a heavily loaded boat to displacement speed. Similarly, only modest horsepower is need to maintain a wheeled vehicle at speed on a paved road that is level.

User avatar
Dutchman
Posts: 604
Joined: Wed Oct 14, 2015 7:48 am
Location: Kalamazoo, MI (South Haven)
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby Dutchman » Fri May 04, 2018 2:21 pm

jim all true what you said. But the truck seats 4 or maybe 5 and its WOT with full crew is no different than with just the driver no matter what which engine is opted for in contrast to an under powered Whaler boat. I'm not talking stowage of the truck or every nook and cranny of the boat, we are talking people allowed (truck-# of seat belts ; boat- # of persons per USCG)
Take the analogy a step further. A cruise ship runs WOT as fast with 200 crew as it does with 2000 passengers full displacement, semi-displacement or planing hull is not the point the point here is that the vessel does not perform as it should and maybe was designed for.
EJO
"Clumsy Cleat"look up what it means
50th edition 2008 Montauk 150, w/60HP Mercury Bigfoot

jimh
Posts: 5445
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby jimh » Fri May 04, 2018 2:49 pm

DUTCH--your claim that trucks suffer no decline in performance with the total weight of the truck and crew cannot be true. As I mentioned, the effect is probably masked because most driving is on level roads where there is no effect of deceleration from gravity to overcome and only rolling friction and aerodynamic forces must be matched with power to maintain speed. If driving up a steep grade, you would notice the change in performance with added weight. The Physics of a truck going uphill and a boat on plane are the same: both are trying to accelerate against gravity.

There is no boat whose performance does not decrease with increasing weight. In your example of a cruise ship, the difference in total weight is very small for the weight of 2,000-people. Assume the people weight 175-lbs, so 2,000 people weigh 350,000-lbs. The total weight of a "cruise ship" is likely to be about 100,000-tons or 220,000,000 or 220-million-pounds. The weight of 2,000-people as a percentage of the displacement weight is then

3.5 x 105 / 2.2 x 10[sup]8 = 1.59 x 10-3 = 0.00159 = 0.159-percent.

If you want to make a valid comparison, you get to change the weight of a 190 MONTAUK by 0.159-percent while it is moving at displacement speeds--cruise ships never get onto hydroplane, at least not ones that carry 2,200-people.

If we assume the total weight of a 190 MONTAUK with 115-HP is as mentioned in the performance report, 2960-lbs, then the allowed increase in weight will be

2.96 x 103 x 1.59 x 10-3 = 4.7-lbs

So, please, tell me how much difference in performance will occur by adding 4.7-lbs to the test weight of the 190 MONTAUK with 115-HP engine when the boat is operating at displacement speeds? I look forward to learning the answer.

jimh
Posts: 5445
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: 190 MONTAUK with 115-HP is Under-power

Postby jimh » Fri May 04, 2018 3:14 pm

A good indication that DUTCH's analogy of boats and trucks is flawed is easily detected by the amount of fuel used by the engines to maintain them at a certain speed. I can keep my boat on plane at 27-MPH by burning about 10-GPH. I can keep my truck in motion on a level road at 54-MPH burning about 5-GPH WHILE I AM ALSO TOWING THE BOAT AND THE TRAILER.

Now you do not have to be Leonardo to figure out if one engine burns 10-GPH just moving the boat in the water while the other engine can move the boat, its trailer, and a truck at the twice the speed on the road with about half as much fuel, there must be some reason. The reason is that the boat is much harder to move through water at 27-MPH than the truck is to move on a level paved road at twice that speed. On the basis of fuel consumed we can see the boat is a the very least FOUR TIMES HARDER to move. (The truck has to move itself and the boat; the boat just moves the boat.)

If you want to make an analogy about effect of weight, you better take into consideration the boat needs at least FOUR TIMES as much horsepower per pound to move on plane as the truck does on to maintain speed on level pavement.

The problem is not that trucks are immune to change in power-to-weight ratio, it is just that most of the time you never see much effect because the truck is not constantly trying to accelerate against gravity.

If I try to drive my truck uphill on a steep grade while pulling the boat and trailer, I am sure the fuel flow rate begins to climb drastically, and the ability for the truck to accelerate declines very significantly. On some steep grades it is very difficult to maintain speed, and the truck transmission must be down-shifted to a lower gear in order to continue up the grade. Now we clearly see the effect of weight on the truck's ability to accelerate under load.