Size of outboard

rbronston

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Aug 30, 2022
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Hello, Im a newbie to boating. I have a 16 ft 1999 sea nymph 160 fm. It is rated to up to 70 hp. I don't think i Need that nor can I afford that. Will I be good with a 30-40 hp on it. I won't have more then 3 people onboard at a time.
 

briangcc

Commander
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Jul 10, 2012
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2,360
Umm define good.

Will it move with that load...yes. Will it plane...doubtful. Will it break any speed records...not likely.

Rule of thumb has been 75-80% of factory rated HP as a minimum. So I'd be looking in the 50 & up class.
 

Scott06

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Apr 20, 2014
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Umm define good.

Will it move with that load...yes. Will it plane...doubtful. Will it break any speed records...not likely.

Rule of thumb has been 75-80% of factory rated HP as a minimum. So I'd be looking in the 50 & up class.
Agreed you want to be over 80% of rated or you will have a dog...

My friend has a similar sized boat with 70 merc (2 stroke) and it is adequate with that
 

Silvertip

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Sep 22, 2003
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I once owned a 16 foot side console with a 40HP Evinrude and was never in anyones way. It would plane nicely. 30 HP is a stretch, but 40HP will do the job.
 

Cortes100

Petty Officer 2nd Class
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Apr 30, 2006
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I have a Starcraft Stealth 16'. The tag rates it for max 90hp.
It has a Merc 60hp 4 stroke and moves along quite nice. No problems with holeshot, planing or speed. I usually cruise around 23-25mph. WOT is 33mph.

20220729_124406.jpg
 

Chris1956

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Mar 25, 2004
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A light 16' footer with a 40HP big twin was pretty standard in the 60s. 25MPH was the max cruise.
 

JimS123

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A light 16' footer with a 40HP big twin was pretty standard in the 60s. 25MPH was the max cruise.
Back in the '60's I ran a 40 HP Rude and it worked quite well. Then, some of my neighbors went to 75's and I just HAD to go just as fast as them, so I upgraded to a 60 HP Triumph. It didn't make me have more fun.

The bottom line is do you want to go boating with the family and have memorable days, or be the showoff?

A 40 will do you just fine. The 75-80% "guideline" is for people that have sufficient money to spend and can never be satisfied.
 

Beagleville

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Jul 30, 2017
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Back in the 60's most boats were flat bottomed and a 40 worked well. If your Sea Nymph is flat bottomed the 40 will work for you, too, but it's probably a medium V which will ride better but will require more power.
 

Scott06

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Back in the 60's most boats were flat bottomed and a 40 worked well. If your Sea Nymph is flat bottomed the 40 will work for you, too, but it's probably a medium V which will ride better but will require more power.
Agreed also likely lighter especially with a 2 stroke vs the newer and heavier 4 strokes
 

airshot

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Jul 22, 2008
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I have a very similiar boat, mine is a Sylvan 16' side console. Mine has 3 group 31 batteries and a marine starting battery ( heavy). With two adults and my gear mine will do 30 mph and 32 with just me. Gets up on plane well and actually performs quite well. I have a 1992 40 hp Merc 2 stroke, 4 cylinder outboard on it. Unless you plan on pulling multiple skiers, you should be fine. One thing I will add, is that my motor has power trim and that does nake a big difference !! I can get an extra 3-4 mph just from getting the trim right on the money. When I was a kid, my dad had a 16' Lyman with a 35 hp jonson golden jubilee on it and we pulled up two skiers all day long
 

nola mike

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Sounds like some jealousy. Why don’t you keep your condescending comments to yourself and just answer the guys question.
Talk about a showoff, @Scott06. You have like, 230hp! I agree though, 70 hp IS pretty ostentatious. /s

Also, the difference in price between a 20 yo 40hp and a 20 yo 70hp is less than the gas money needed to launch it. Still waiting for the "I have too much power, and can easily get on plane with a loaded boat" post.
 

JimS123

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Sounds like some jealousy. Why don’t you keep your condescending comments to yourself and just answer the guys question.
I DID answer the question. Back when I was a kid and had limited funds I ran smaller engines. And, I was quite SATISFIED with that and didn't NEED to go fast. The problem today is that way too many people just aren't happy with anything.

BTW, my 2 newest current boats are equipped with the max. HP they could take. It's funny though, they always get run at 20-25 mph.....LOL.
 

robeffy

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Aug 10, 2014
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Hello, Im a newbie to boating. I have a 16 ft 1999 sea nymph 160 fm. It is rated to up to 70 hp. I don't think i Need that nor can I afford that. Will I be good with a 30-40 hp on it. I won't have more then 3 people onboard at a time.
I have a 93 FM161, with a 40 hp 2 stroke Evinrude. With 1 person, I get around 28 mph, with 2, 23 mph, with 4, it will barely plane. Its rated for 60 hp. More than once I wished I had more hp. Those mph ratings are the built in speedo, no idea how accurate that is.
 

JimS123

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I have a 93 FM161, with a 40 hp 2 stroke Evinrude. With 1 person, I get around 28 mph, with 2, 23 mph, with 4, it will barely plane. Its rated for 60 hp. More than once I wished I had more hp. Those mph ratings are the built in speedo, no idea how accurate that is.
Get a good tach and check WOT rpm. Then replace the prop with the appropriate pitch. I had that same motor on a heavier 16 footer and 4 people were fine.

Prop optimization is often overlooked. Many boats thought to be underpowered can perform adequately with the right setup. Of course, if "speed' is the main objective, that simply takes HP.
 

airshot

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Jul 22, 2008
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I have a 93 FM161, with a 40 hp 2 stroke Evinrude. With 1 person, I get around 28 mph, with 2, 23 mph, with 4, it will barely plane. Its rated for 60 hp. More than once I wished I had more hp. Those mph ratings are the built in speedo, no idea how accurate that is.
Probably not very accurate, I use my gps for all speed tests. Cant believe you would get a 5 mph drop for adding one passenger. With a gps, you might find a better spot for your trim setting which could gain you some mph....
 

rbronston

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Aug 30, 2022
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Hello, Im a newbie to boating. I have a 16 ft 1999 sea nymph 160 fm. It is rated to up to 70 hp. I don't think i Need that nor can I afford that. Will I be good with a 30-40 hp on it. I won't have more then 3 people onboard at a time.
Thanks. I'm not much into speed. Just wat to fish on the weekends. The boat is light and planes easily.
 

matt167

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Sep 27, 2012
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4,151
I have a 2021 Suzuki 25hp and a 14’ StarCraft holiday. Powers it decently but wont win a race. I ran it with a big twin 40 and it was just quicker to plane, not really that much faster
 
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