Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Minimum HP performance

Posted by Bachus12345 on 03/30/08 - 7:59 AM
#1

Hi Folks, I have a perfectly restored 1966 Nauset.
I am in the process of selecting an outboard engine and have narrowed my search to both Honda and Yamaha 4 stroke engines.
I am in South West Florida so will most likely select Yamaha because the dealer network is the largest here.

I am looking at a modest engine; 50-60 hp...that is it.

I plan to se the boat for joy ridding, fishing in the bay and going to the beach.

I don't want to pay a lot for an engine that you thow away after 5 years and I don't need to go very fast, I also don't want to suck down the fuel......I'm happy if I can get up on a solid plane with 2 people on board and clip along at about 25-30mph.

The Whaler specs say that it recommends as a minimum 35hp for this boat.

Why?

Is that the magic HP number to get up on a plane with 2 people on board?
Does anyone have any experience with running the smaller engine sizes?

When I was a kid the biggest thing on the block was a 40-50hp and that is what I used to see on this boat back in the mid 1960's.....why is everyone pushing 100hp plus????

Is this just the same problem we have with the big V-8 pick-up truck craze and SUV craze?

Anyone running a smaller engine out there????

Posted by lennell on 03/30/08 - 8:24 AM
#2

A friend of mine runs a 1980 Montauk with a 55 hp Suzuki 2 stroke and with the two of us on the boat he gets about 28mph top speed. Hope this helps.

Posted by Phil T on 03/30/08 - 8:43 AM
#3

Let me welcome you to WC.

Could you explain your statement:

I don't want to pay a lot for an engine that you thow away after 5 years


I know dozens of boat owners who own 1980-1990 boats with same year engines with hundreds of engine hours in salt water so your statement appears opposite of my observation. My guess on a marine outboard engine life-cycle is 700-1000 engine hours if maintained. At 50 hours a year, that is a long time.

While the maximum horsepower for your Nauset is 90 hp, I see many Nausets with a 70 horsepower 2 strokes. If you prefer a 4 stroke, a 50-60 hp 4 stroke would weigh about the same. Given the age of your transom, engine weight should be taken into consideration.

Additionally, consider a smaller engine will run more RPM's to reach 30 mph in contrast to a larger engine. I had a 90 hp on my Montauk and have a 115 hp on my Outrage. While I can go 40+, I often cruise at 28-30 mph.

Take a look at this great reference article on engine choices by Joe Kriz.

Hope this helps and again, welcome.

Posted by danedg on 03/30/08 - 10:31 AM
#4

Bachus,
Welcome aboard!
I've posted many comments here extolling the virtues of the 60HP 4 stroke on my Nauset...it's strong, reliable and efficient. All motors on the boat have been 60 - 70 HP...none of them seemed to have a problem achieving plane in a fully loaded boat. The current Suzuki has proven to be the best so far....
I wouldn't put less than a 50 on one...and I think a 90+ is a bit much...but that's just my opinion after 45 years...the rest of the members here are not bashful about sharing theirs....:)
This subject comes up a lot!
My motor is now 8 years old with 756 hours...
I anticipate running her for a number of years to come...Suzuki estimates 10,000 hours of life expectancy...

Edited by danedg on 03/30/08 - 10:34 AM

Posted by ioptfm on 03/30/08 - 1:15 PM
#5

You may also want to consider the point that if the boat is under-powered you will be running at a higher RPM rate to attain a crusing speed, thus hight fuel consumption, whereas with a higher HP you will be attaining the same speed and comfort while the motor is in cruising speed. Better gas consumption and less wear and tear on the motor. I agree others in that I do not understand your statement of using a motor for only 5 years. Many of the newer motor have a 5 or 7 year warranty with them

Posted by Davidk on 03/30/08 - 1:20 PM
#6

Well I'm ready to chime in now. I just ran my 1963 Nauset for the first time in 15 years. It has a freshly installed 100HP Yamaha 4 stroke (2001 carberated). Here's what I got today with 5-10kt winds and slight chop. I maxed out at 6200RPM (I likely have the wrong prop). At full trottle I got 42.5 MPH. At a cruise speed of 3700 RPM, I ran about 23 MPH. At 4000 RPM, I ran about 28-29 MPH. In an hour and a half I burned about 3 gallons of gas (15 minute no wake each way) - the rest of that time was between full trottle and cruise. Of note is my boat is on the heavy side with alot of wood decking in the bow, and stern seating as well.

When I put the right prop on, I will probably loose a couple of miles per hour on the top end.

Posted by Bachus12345 on 03/30/08 - 3:49 PM
#7

Hi Folks,

When I lived up north like the majority of your folks I also ran my boat very little.
So I do understand went the man from Casco Bay says he has an old engine and it's going strong....that's because you hardly use it.

In Florida I use the boat 6 hours on Saturday and another 6 hours on Sunday. I also run it 3 week nights for a few hours each evening. I average about 15-20 hours per week. I use the boat for about 50 weeks out of the year....that's about 1000hrs.
That is why outboard motor boat engines do not last very long in South Florida.
After about 5 years you are tossing it or trading what's left of it in.

I know when your getting dumped on with snow like Maine had last week and your stuck with wet drizzle most of the year it's hard to understand that a lot of us boat year round and enjoy 70-80 degree sunny weather!

Posted by Bachus12345 on 03/30/08 - 5:18 PM
#8

Here are some pics of the Nauset I just finished, it has a brand new mahogany consol and seat, just needs that engine.
Based on what I am hearing I will place an order on Monday for a 60hp 4 stroke high thust Yamaha and live with it.

Posted by Joe Kriz on 03/30/08 - 8:03 PM
#9

That is why outboard motor boat engines do not last very long in South Florida.
After about 5 years you are tossing it or trading what's left of it in


To bring this back into reality, not all motors, nor all boats in Florida get used heavily.
I'm sure some boats get used more and some boats get used much less.
To look at the big picture around the world, it depends on the user and can also depend on what part of the country they are from.

First:
Which engine is going to last longer?
60hp that has to turn 4000 RPM to push a boat 30 mph for 1000 hours
or a
90hp that has to turn 3000 RPM to push a boat 30 mph for 1000 hours?

Second:
Given the above, which engine will use less fuel?

There are a lot of variables in the above suggestions but the common mistake many people choose to believe is that a smaller engine will give them better fuel economy. This is really NOT the case. The smaller engine will generally NOT last longer because it has been worked much harder.

Just food for thought and I encourage everyone to think about the BIG picture.
This is the World Wide Web and we have Whaler owners around the world in different climates and some of them use their boats more than others no matter where a person might be located.

We all need to think about the above questions and try and figure out the best engine for us using any and all variables. Bottom line, whatever fits your needs and your pocket book.

Edited by Joe Kriz on 03/31/08 - 11:20 AM

Posted by Binkie on 03/31/08 - 10:00 AM
#10

Joe,
To bring this back into reality, not all motors, nor all boats in Florida get used that much.
I have to disagree somewhat. Its true that boat owners who baby their boats, their equipment will stay nice indefinitely. Most boats are not babied and kept covered in yards or garages. The boating season is 12 months a year. A motor stored in the open or even worse, in salt water will get scorched by the sun in just a few years.
I have a `58 Evinrude 35, from Wisconsin, a `56 Evinrude 30 from upstate NY, and a `87 150 Suzuki, from Mo. and they are in far better shape cosmetically and have better compression, than the `99 Johnson 25 I just bought that spent its life in S. Florida, in the sun. The only reason I bought this motor was I don`t seem to have good luck when receiving shipped motors. Always some king of damage during shipping.

rich

Posted by Joe Kriz on 03/31/08 - 10:19 AM
#11

Binkie,

Maybe you are misunderstanding what I am saying.

I am saying not EVERY boater in Florida uses their boat everyday and therefore has to throw their engine away every 5 years....
Every boater is different even though they might live in Florida.
Not every boater in Florida leaves their boat out either.
That's all I am saying....

Posted by ioptfm on 03/31/08 - 5:37 PM
#12

I've got to add one more thing. I have been told by several mechanics that when you are shopping for a used outboard motor, shy away from one that was used on a pontoon boat. They are usually run at WOT the majority of the time. Same principle with a boat that is underpowered

Posted by Derwd24 on 03/31/08 - 9:07 PM
#13

Io, I was told the same thing by a good mechanic a number of years back, but he stated the opposite reason - said pontoon motors spend too much time running at low speeds by people trolling around all day and don't get the chance to burn off all the deposits by high speed running. For whatever reason, probably good advice to heed by steering clear!

Posted by number9 on 04/03/08 - 11:04 PM
#14

Recently purchased a great 1984 18' Outrage without power with t-top. Minimum recommended is 70 hp 25" shaft. Had a recently purchased leftover 2004 Yamaha 50 hp High Thrust with a 21" shaft. Decided to give it a chance since it was sitting around and after spending some time calculating Whaler hull forms, weights, and expected top speeds with different hps. With a black stainless 13 1/2 x 14 prop and full 64 gallons of fuel the boats performance far exceeds my expectations. Quick to get up on plane and easily cruises at 22 mph a bit over half throttle, top end is close to 30. The slightly longer High Thrust shaft on the T50TLR, larger gearcase with lower gearing and larger diameter prop seem to get the necessary bite in the water and only get some cavitation if sharply turning without lowering power setting. Added benefit of the shorter shaft is reduced drag and draft. After getting my tach installed and do some mpg calculations will share that information if ya'll are interested.

Posted by Bachus12345 on 04/04/08 - 7:05 PM
#15

Nice to hear about your performance with a "normal" engine!
Everyone is so power and speed crazed that it's hard to explain that some of us just don't need to go 50-60mph in a 40 year old boat and don't want to gulp down the fuel.
Like the SUV craze most outboard boat owners seem to feel that bigger and faster is better.
When I was a kid 40-50 HP was big........in the late 60's motor cycles that you would see on the road were small and 450cc was considered a big bike.
Back then very Whaler I saw that was 17' ran a 40hp johnson/merc/evenrude 2 stroke and we were all very happy with them; and I lived about 10 miles from the factory in Mass. and we had more Whalers around than any place else.
Why then am I being told, more than I want to hear ,that I have to hang a 90-100hp to "get the performance I need" ??????
You seem happy and I am glad to hear it.......

Posted by danedg on 04/05/08 - 5:03 PM
#16

The 60 Hp 4 stroke of which I speak so highly...spent it's first four years in salty...
Damned near killed it.....
...it took nearly 75 hours of "fresh water" to flush out all the salt, sand, and stuff:(
that motor sucked up in it's first 178 hours.....(4 years)
Recommended service procedures have replaced most of the cooling/lub/lower end parts...and she seems to have survived quite well....at 785 hrs.....(7 years)
despite the marine onslaught and initial general neglect....
which is why I respect this particular motor....
with a bunch of TLC...it's considered reliable.....
But...A motor in brine/ 1000 hrs/yr?
I'm with CBO....five years.....

Edited by danedg on 04/05/08 - 5:06 PM

Posted by Tarpun on 04/20/08 - 10:29 AM
#17

Bacchus,
Good luck with your new motor! I'm sure for the way you use your boat that and for your locale you'll be satisfied with it's performance. I also do not see the need to be able to run @60 or 70mph. However some of us do have the need for a little more power. I am currently replacing the 1979 85 hp. Evinrude with a '96 model 115hp Evinrude. The old motor ran well even though it had a pile of hours on it. About 37 mph wiht a full load. Most of my cruising and running from spot to spot was done at 22-24 mph. I very seldom ran any harder. I have run a whaler with a 70 hp 2 stroke and for my uses I prefer a few more cubes. One big reason is that I'm likely to run out the inlet on spring day to chase cobia and sometimes the wind kicks up and the tide turns and I want plenty of power to come in with. Reason #2 is that I often fish the flats and if I can find a deeper hole 30' across I can jump on plane. I generally run with18-24gal. of fuel and a 24 volt trolling motor. The reason for the 115 is that it was a deal. If I was to buy new it would probably be 90 Etec. I would be very interested in your performance numbers when yo get it dialed in. Tight lines and fair seas.