Will my 70HP be enough

[jaurora]

I am looking into a 19' center console which is all fiberglas made in 1987. I current have a 1977 70HP evinrude pushing a 1963 16' chriscraft. acordint to my handheld GPS the boat did 35MPH on the water with gear and 2 adults. My chriscraft is a very heavy boat. Mostly wood wrapped with glass. It is a tri hull with 2 built in water tanks in the rear to staiblize the boat. I had a rip in the pottom from the trailer so I know the wood on the boat was swelled up and weighed down at the time.

I am just wondering in the meantime do you think this 70hp will push this boat without stressing the motor? I found a website in which you enter the motor information and then the make model year of the boat and they give you a recomended prop which turned out to be a 13 3/4" X 15".

Please let me know what you think. I am not looking to be a speed boat and I dont really travel long distances. Just use the boat for fishing.

thank you for your ideas and comments.

J

 

[Silvertip]

Re: Will my 70HP be enough

That prop would be about right for the application. It at least gets you in the ballpark.

 

[BF]

Re: Will my 70HP be enough

what is the new boat rated for? If it's rated for more than about 90hp, I think 70 would be too little. If it's rated for 90 or less, a 70 would probably be reasonable (but no speed demon). First impression was that a 19' boat sounds pretty big for a 70. If it has lots of deadrise, it'll take more power to get on plane than a flatter bottom boat.

 

[jtexas]

Re: Will my 70HP be enough

"without stressing the motor? " ........ prop it to run 5000 RPM at WOT, it'll be fine. 35mph is doubtful however.

 

[kenmyfam]

Re: Will my 70HP be enough

You dont know until you try it. 75% of max rated HP is a good rule of thumb for a minimum.

 

[Dakota47]

Re: Will my 70HP be enough

it should be fine, its not going to stress the motor. its just pushing water..

 

[Frank Acampora]

Re: Will my 70HP be enough

The 70 will get it on a plane but look for speeds in the high 20s. That doesn't leave much reserve power if weather turns bad and you want to make shore fast.

 

[studlymandingo]

Re: Will my 70HP be enough

If the 19'er is fiberglass, speeds in the high 20s is probably a bit optimistic. I would guess the max rating to be closer to 200HP. As everyone has stated, if the 70 is propped to run in its max RPM range, then the motor will be fine; it will just be you who is a bit stressed when the guy in the canoe blows by you!​

 

[kenmyfam]

Re: Will my 70HP be enough

If the 19'er is fiberglass, speeds in the high 20s is probably a bit optimistic. I would guess the max rating to be closer to 200HP. As everyone has stated, if the 70 is propped to run in its max RPM range, then the motor will be fine; it will just be you who is a bit stressed when the guy in the canoe blows by you!​

Canoe would have to be equipped with high pitch paddles though !!! LOL

 

[Solittle]

Re: Will my 70HP be enough

If you have it try it though I suspect you will find the performance wanting. In my book rule of thumb says a 115 is adequate for a 19'er.

 

[kenmyfam]

Re: Will my 70HP be enough

If you have it try it though I suspect you will find the performance wanting. In my book rule of thumb says a 115 is adequate for a 19'er.

I'm with that opinion but like said, if you got it then try it !!! you may be satisfied.

 

[jaurora]

Re: Will my 70HP be enough

Thanks guys for all the input. I had a feeling it would be under powered but unfortunatly the finances do not hold enough room at this point to repower in which I would love to do.

 

[Rancherlee]

Re: Will my 70HP be enough

It should be fine, might be hard to get it to plane out though. My friend has a 21' Starcraft center console striper model (just the console and a bait well) with a 110 crossflow on the back and its struggles pretty hard to get on plane and runs out at 34 mph. His is rated for a 150

 

[Lowranger]

Re: Will my 70HP be enough

a 19' boat sounds pretty big for a 70

It depends on the boat and how you use it. I run a Johnson 70 on my 3500# 22' C-Dory and she planes clean @10 and tops out at about 25 mph with a 14"X13" aluminum prop. She'll be 18 years old this Saturday.