I believe my motor is under powered

Hi all, been lurking for a while and found lots of useful info.
I have a 15' Smokercraft Alaskan with a 4 stroke 15hp merc. Is it the fact that its 4/stroke or is my motor just too small? I have a 24 volt trolling motor with 63lbs of thrust that seems to push my boat as fast as the motor.

You may be/are underpowered if your hull is rated for 35hp and you have a 15 4s on it. Check to see if the cave plate is about even with the bottom of the hull, and how much weight you carry affects it a lot as well.

A 15 hp should be able to push a 15' aluminum boat 15 to 20 mph, depending on how much load you have in it, what prop does it have? It may be propped for power and not speed. A large diameter prop with low pitch for power and small diameter prop with high pitch for speed.

Its the factory prop, I bought this boat new. I usually have me and the wife in the boat and a bit of fishing gear. I will check the cavplate . its rated for 35 and I am not worried to much about speed but just seems so slow

You need to determine your props pitch

You may want to go 4 blade as well

Underpowered is my vote. You need at least a 20 on that thing, but I would want at least a 25 on a 15ft boat.

have you put a tach on it to see if the motor is in the right RPM range? i ended up putting a 4 blade 9p on my 20 and that made a huge difference! stock was a 10P 3 blade. and that motor is a little small for that boat. i have a 20 on my heavy 1448SC and still need more hp.

I have the exact same boat with a 20hp Yamaha tiller four stroke. I fish it inshore/nearshore around the Oregon Inlet area on the Outerbanks of N.C.

I'm 330lbs and solo (w/ trolling motor/battery, fishing gear, and full tank of gas), I get 24mph WOT when it is calm on the bayside. Can take a bit to get up on the plane with all the weight up the back, so I typically add a cinder block or two next to the battery in a box up front. I often feel underpowered too when on the ocean side and am currently looking to pick up a slightly larger more versatile boat. I've considered upping the horsepower myself to the 35hp max recommended power but I'm not entirely confident the hull of the boat would be up to the extra pounding. Bit of background - I'm an Aussie from the Barrier Reef who grew up fishing Quintrex aluminum boats well offshore. The Smokercraft has been good to me inshore and feels quite capable in most any inshore/bayside settings but is not nearly the same quality build of the heavy duty aluminum boats we have back in Oz and that is really noticeable once you put it in the ocean.

Further info on the Smokercraft - I fish inshore with my father in law and brother in law a bit (both around 180lbs each) and still get around 18mph WOT. It can be tough to get on the plane with three folks in the boat but is comfortable enough and still feels safe inshore.

We've added a fourth a time or two when the other brother in law is in town but that is well above the max load capacity... while the boat still floats, she barely moves at about 8mph. Recommended only for short distances and with folks who are highly familiar with one another

Cheers,

Craig

my 15 feels underpowered when i fish high altitude lakes.