Trust the dealer?

[Trudging]

Just put an order In for a new aluminum boat. It is primarily for fishing small to medium fresh water lakes with two adults. I have chosen a sixteen foot boat weighing in about 300 lb. I hope to have a top end speed of roughly 25 mph. Dealer advises one of the new lighter 20 hp 4 strokes. Is this enough engine?

 

[dingbat]

Just put an order In for a new aluminum boat. It is primarily for fishing small to medium fresh water lakes with two adults. I have chosen a sixteen foot boat weighing in about 300 lb. I hope to have a top end speed of roughly 25 mph. Dealer advises one of the new lighter 20 hp 4 strokes. Is this enough engine?

It would push a #300 boat at speed. Not sure about adding two “adults”.

Bear in mind an “adult” in boating terms weighs #150

 

[racerone]

Need 30 HP for this.

 

[Scott Danforth]

welcome aboard.

Just put an order In for a new aluminum boat. It is primarily for fishing small to medium fresh water lakes with two adults. I have chosen a sixteen foot boat weighing in about 300 lb. I hope to have a top end speed of roughly 25 mph. Dealer advises one of the new lighter 20 hp 4 strokes. Is this enough engine?

how loaded will you be? just yourself? yourself and 3 buddies?

as indicated above, it is assumed the average adult is 150#. some of us famine proof boaters are over 200#, some close to 3X what the average adult weights.

so how much are you adding in terms of weight? gear?

the old fishing barge I inherited from dad is an old 14' aluminum boat with a 12hp. it will plane with 1 person, however not with two. with a 20hp on back, it will plane with two, however not be anywhere near 25mph. with a 25hp, it was close to 22mph with two people.

some boats from my past needed over 30hp to reach 25mph.

 

[Sea Rider]

Yep, if not on a tight budget go for a 30 HP motor, will have more water fun and speed than with a 20 HP one.

Happy Boating

 

[Alumarine]

A friend has a 16ft Lund SSV that weighs about 350 lbs with a 20hp honda.
2 of us in it is another 300, 2.5 gallons fuel and a 20 lb anchor so less than 400 total.
We get about 22 mph.

 

[JimS123]

My old Starcraft Utility weighed 450# (deluxe model with floor) and it would reach 25 mph with a 25 HP 2-stroke and 2 people.

Propped right, your 20 will "perform" OK, but not at your desired speed. Go with a 30.

 

[nola mike]

My Carolina skiff probably weighs about 300#. 25 hp 2 stroke hits 28 mph with me aboard, 25 easy with 2 adults. I can pull my kids skiing with it.

 

[Scott06]

Agree with the others I think 20 would be a little low. What's the max hp rating of the boat? I'd think you want to be close to the max rating.

 

[ahicks]

Do NOT trust the dealer unless it's in writing and signed by an owner or manager.

 

[rjwilliams11741]

Just put an order In for a new aluminum boat. It is primarily for fishing small to medium fresh water lakes with two adults. I have chosen a sixteen foot boat weighing in about 300 lb. I hope to have a top end speed of roughly 25 mph. Dealer advises one of the new lighter 20 hp 4 strokes. Is this enough engine?

I would opt for the maximum hp allowable for that particular boat.

 

[Sea Rider]

In reality you can power large light alum boats, Ribs with whichever portable motor you prefer from as low as 8 HP to 30 HP ones ideal for fast displacement to extra fun plane speeds. More efficient hull designs requires less HP motors to less efficient ones that's comparing 2 boats with equal lenghts.

Wth 2 up, fishing gear and motor well propped that's with at least one less pitch from factory delivered ones a 20 HP will perform very well, cost less and burn less fuel than a 30. The issue is that very few boaters goes for a prop maximization from a medium pitched factory delivered prop, prefer next higher HP motor and guess what delivered too with a medium pitch factory installed prop. LOL!! Now a days with high fuel rates will be insane to run a motor at full throttle for long distances on constante basis unless fuel costs it's of no importance to your economy. OTOH what's the point of having a speed demon motor for fishing small to medim large lakes ?

Happy Boating​

 

[JimS123]

Now a days with high fuel rates will be insane to run a motor at full throttle for long distances on constant basis ​

Not nowadays, but it was ALWAYS that way.

OMC owner's manuals always referred to the term "cruise throttle". When at WOT you would merely back off the throttle a bit until you heard a slight reduction in engine speed. At that point you were saving a lot of fuel, but the speed reduction was only slight.

Sure adds to engine longevity as well.

 

[racerone]

Friends of mine used to have a 35 HP 1959 Johnson in the family.------Then graduated as funds allowed.----New 1966 model 100 HP Johnson on a bigger 17' boat.-----The father said ---" You know this 100 HP does not use that much more in the way of fuel "-----Much of that is due to the fact that the 100 HP did not have to run at full throttle.

 

[Sea Rider]

Not nowadays, but it was ALWAYS that way.

Surely it's been always that way, but right now the fuel cost has got much worse to the point I'm driving and boating much less than used to before speculative fuel prices skyrocketed way high. Going back to the OP's post : Which 4 stroke 20 HP motor brand was the dealer recommending going for ? Which 16 footer alum boat brand are we talking about to know its max HP and passenger capacity rated for ? Each motor manufacturer have their own speeding and fuel comsumption parameters...


Happy Boating​

 

[JimS123]

but right now the fuel cost has got much worse to the point I'm driving and boating much less than used to before speculative fuel prices skyrocketed way high. ​

I got my first boat at age 19. My hourly wage back then would buy 3 1/2 gallons of gas.

A few years later, after graduating from the University, my hourly salary would buy me 10 1/2 gallons of gas

Today retired, my annual income / 52 / 40 would buy me 11 gallons of gas.

It's all relative.

The larger the motor, the larger the capital. The larger the motor, in all probability, the lower the fuel usage.

The longer you wait to buy a bigger motor, the more efficient the motor will be. Technology is always improving.

 

[RMClark]

My 2021 Merc 20HP will push my 14' Aluminum Lund at 23 mph.

That speed is loaded with two fisherman, added wood decks, fuel, gear, battery, trolling motor, and anchor.

 

[racerone]

Yes per post #15----It has always been that way.-----But there are many novice boaters today that do not understand the concept of fuel consumption on boats / outboard motors !!

 

[wooky30014]

Back quite a few years ago my Uncle rigged a 35hp Merc on a 12ft Sears V-hull and mounted the steering and throttle lever on the front seat. He had to sit on the floor in order to drive it and although I didn't see this contraption run he told me it scared the outta him. My Cousins also got to drive it with the same result. It was dismantled soon after with being "too dangerous" as the reason. Your call on what hp to set on any particular hull. I once had a 14ft LoneStar rated for a 50hp and it had a 45hp Chrysler on it and that was plenty for me, it was up on plane within 3 feet of firewalling the throttle lever. As far as consumption goes, if I pulled back a little after getting up on plane I could literally ride all day on a tank of gas (but who runs slow like that "just up on plane" ??, not me)

 

[909]

Trust your gut, not your dealer

There's no replacement for displacement