Sea Nymph transom size & motor recommendations?

[TwoRivers]

Just picked up a 1990 Sea Nymph 19ft. Striper. It has a 70 hp. Evinrude long shaft on it.
Not sure the motor came with the boat originally?
Motor runs fine except the boat is rated for 140 hp.
Looking at higher hp motors but I not sure about what shaft length to look for.
I know, just measure the transom from the top to the point at the bottom, right?
Too much junk in the way, t&t , transom bracket etc.
Can't tell for sure exactly what it measures but seems to be more than 20 inches.
Does anybody know if this particular boat takes an extra long shaft motor?
Also, any thoughts on how big a motor to look for.
Intend to use the boat maybe six times a year to fish lake Erie.
thanks in advance for your consideration

Will post photo once I learn how to resize them again.

 

[JimS123]

See where the anti-cavitation plate lines up with the boat bottom. If its OK, then check the model number of the engine to see what length it is. Viola, you got your answer.

As an option. lay a twobyfore on the transom, with it sticking out back. Level it and measure the distance to the ground. Then crawl under the boat and measure the distance from the keel to the ground. A-B is the transom height.

 

[TwoRivers]

Thanks, Jim.
Should have paid more attention during geometry class.
According to the model number the current motor is a standard long shaft.
I'll crawl under and measure once it stops raining.
Anybody out there have one of these relics?
What motor are you running?
thanks
rob

 

[Bondo]

Can't tell for sure exactly what it measures but seems to be more than 20 inches.

Ayuh,...... Generally speakin',... Outboards are 15",..... 20",...... or 25",......

 

[TwoRivers]

Thanks Bondo,
In the Evinrude motor ID chart they additionally list a 22.5" and 30".
My transom seems a little longer than 20 but shorter than 25.
I'll measure to make sure.
I've never seen a 22.5 or 30 inch shaft motor but with my luck I probably bought a boat that requires one?

 

[ahicks]

Myself, I would have no trouble running the 70 if it was doing everything I wanted it to do. On a lightly loaded fishing boat there's no need to run max power. I'm not sure of this boat's design, but a lot of boats can only go so fast in a chop without beating the snot out of boat and occupants, making that heavier faster motor useless.

Bottom line, I'd suggest you run it for a bit to see what you think. If you do decide to go bigger, watch the weight carefully. There can be quite a jump from the small 4 cylinder engines (90-115hp) to the next size up (120+). That's a jump I would avoid, I don't care what the boat is rated for.

 

[TwoRivers]

Thanks ahicks,
I think that's good advice. Never even had the boat out to test it.
From my research I think the 19ft. Stripers came with a 90hp setup?
Read a lot on the forums about bigger is better when it comes to HP.
Been on Lake Erie many times on friends boats, when waves kick up you want to get off ASAP.
Planning to take the boat out to my local lake (Youghiogheny River Lake) soon.
Thanks again.
PS
Can't remember how to post pictures?
Keep getting "Unknown Error" message?

 

[Sea Rider]

If you don't want to go for a larger HP motor, need to know :

What's the max passenger capacity of that boat ?

Number of passengers on board that plan going boating with ?

No need to go for the max HP capacity rated if boating with less passengers than max rated.

Can always go for a prop maximization for motor to run middle to max wot rpm range.

Happy Boating

 

[JimS123]

Thanks Bondo,
In the Evinrude motor ID chart they additionally list a 22.5" and 30".
My transom seems a little longer than 20 but shorter than 25.
I'll measure to make sure.
I've never seen a 22.5 or 30 inch shaft motor but with my luck I probably bought a boat that requires one?

30" motors are quite common in the higher HP models. I never heard of a 22.5. Short shaft transoms usually measure about 16", so if yours measures 21" its built for a long shaft.

Many boaters want the newest, biggest and best, and won't stand for nothing less than the fastest thing on the water. Your Striper is a relatively light boat. Propped correctly a 3 cyl. 70 would be fine for me.

My Sea Nymph is rated for 25 HP. Anything over 18 is dangerous. I settled on a 9.5 and couldn't be more pleased with the results.

 

[TwoRivers]

Measured transom yesterday, just a tad over 20". Feeling better knowing that the regular long shaft motor on it now is the correct length.
Thanks to all who responded.
Will follow your advice and leave things alone for now.
I'll report back after first shake down cruise.
Still trying to post picture?
thanks again.