Family Horsepower

Scouting the classifieds I’m seeing this boat, that boat and if they fit the bill for layout, then secondly if it’s got enough ponies. You see alot of 17-18’boats out there with 90, 115hp motors and that just doesn’t seem like enough to me.

Obviously many factors out there, but the deeper tin vhulls such as older Tyees, Nordics, Phantoms, StarCraft etc what kind of HP would a family of 5 need fully geared with cooler, grill, TM, batteries, to still pull some tubers, knee boards, potentially skiers adequately?

Very little experience in bigger boats, let alone pulling stuff behind them. Any info greatly appreciated.

I had a 1775 pro-v that I bought new with a 115. It was fine for everything you talked about. Ran about 42 mph. Pulled tubes no problem. I repowered with a 150 and that was maybe more than I needed. 115 on a 17′ boat should be fine.

More so depends on the particular boat and rated hp.

As long as you stay within about 25percent of the rated hp on the plate you should be fine.

I will second mojo, I have a 17.5ft v hull with a 115 as well. With 3 trolling motor batteries, 650lbs of people, plus gear I have an awesome hileshot, planes out real quick with a top end of 44 Gps. I would think you would be fine, you can always ask to test the boat as well… Good luck with your boat hunting.

My tournament pro 170 cs is rated for a 115, has a 90 and I can get 38-39mph out of it

have a alumacraft full windshield 17′ 8″ with a 140HP. I can pull tubers and do all the other things fine. max speed with 2 passengers and gear is around 38mph but I believe my boat needs some fine tuning as others with the same/similar rig are reporting speeds reaching 45mph.

I agree with the 25% percentage suggestion because the recommendation factors in the boat. Different boats will require different power.

I have an 18′ Alumacraft rated for 175hp. Bought it used with a 115hp and it was under powered. Bumped it up to a 150hp and it works great. A friend has a similar boat with a 175hp and it is even better.

By better I mean, as they go up in HP they go up in efficiency. The 115hp on my boat got about 3.5mph while running wide open all the time.

The 150hp cruises about 4,000 rpm getting 5mpg while moving 2mph faster than the 115hp when it was running wide open. I can drop it back to the same speed as the 115 and get 6mpg if I feel like being conservative.

Then my friend’s 175hp cruises 3,750rpm vs my 150hp at 4,000rpm. I don’t know his mpg usage though but expect it to better yet.

It may also depend on the lengths of runs you plan to make. I mainly fish Vermilion and Mille Lacs so 25 minute runs each way are the norm. In those cases, the fuel efficiency and speed were helpful. If you are making smaller runs, 5 minutes to your spot, then fuel and speed won’t matter as much.

By the way, I thought the thread was going to be a spin off from the Cylinder Index.

Kyhl wrote:

By the way, I thought the thread was going to be a spin off from the Cylinder Index.

Well it’s always a bonus adding to your CI!

Really helpful info here

Kyhl wrote:

By better I mean, as they go up in HP they go up in efficiency. The 115hp on my boat got about 3.5mph while running wide open all the time.
The 150hp cruises about 4,000 rpm getting 5mpg while moving 2mph faster than the 115hp when it was running wide open. I can drop it back to the same speed as the 115 and get 6mpg if I feel like being conservative.

This assumes keeping the speed constant. Did you ever compare by dropping the rpm’s down on your 115 or something like just on plane?

I’m really curious on this topic too but more so from a fuel standpoint. Think I’m about 1-2 years behind nhamm and staring my research aka dreaming ahead of time.

I have a 17′ Aluminum with a 115… plenty of power.. and if propped correctly, it can be made for speed or power or best of both.

patk wrote:

This assumes keeping the speed constant. Did you ever compare by dropping the rpm’s down on your 115 or something like just on plane?

I’m really curious on this topic too but more so from a fuel standpoint. Think I’m about 1-2 years behind nhamm and staring my research aka dreaming ahead of time.

Sure. That is why I mentioned the length of runs that you plan to make. At the time of my upgrade I would regularly run 6+ miles to a spot. I put on 100 miles one three day weekend last year on Vermilion. Now I’m trying to keep it under 4 miles each way but sometimes I still run 10 miles out.

Note: over 100 miles, that is a difference of 20 minutes of travel time when assuming running at the same mpg but at different speeds between the two motor options. That equates to 20 extra minutes of doing something other than driving over one weekend.

It is up to the guy spending the money how much they value the time savings, only 2 mins each way on 10 miles, excitement level, and depreciation versus the value of today’s dollar. I tend to think that depreciation is similar between the two options, meaning that the higher cost of the bigger option depreciates to a higher number, so effectively the depreciation is the same between both options. Assuming you resell before the value goes to zero.

Keep in mind, I’m not suggesting getting the biggest baddest rig you can. This goes back to my suggestion to try to stay withing 25% of the boat’s rating because outside of that I think you lose efficiencies. Pick out the boat that you like then power it within 25% of the rating.

I also have a 1775 Pro V with a 115 and my adult children pop right up on a wakeboard. Like MOJO, mine also hits 42 fully loaded.

belletaine wrote:

I also have a 1775 Pro V with a 115 and my adult children pop right up on a wakeboard. Like MOJO, mine also hits 42 fully loaded.

Do you know what prop you run BT? I had a 19 pitch 3 blade aluminum on my 1775 Pro V w/ a 115, and it struggled getting skiers out of the water. I went to a 17 pitch, and it seems to have a better hole shot but I haven’t tried pulling anyone with it yet. I was surprised that I only lost about 2-3 mph on the top end. Going from 44 mph top end to 41-42 is virtually no difference imo. So to the OP I would stay away from a 90 hp, but 115 should be fine depending on the boat.

Kyhl wrote:

It is up to the guy spending the money how much they value the time savings, only 2 mins each way on 10 miles, excitement level, and depreciation versus the value of today’s dollar

Yep, I get it. Time vs money. My fuel economy concerns are more about limited fuel. My math is doing 8 days on Rainy Lake without an option to refuel. Questions like: How big is the gas tank? How many gallons per day will I use? How many fuel cans can I take in one trip up the lake? Do I have to back off the throttle(costing time) so I don’t burn more fuel than I can bring up?

My partner’s boat is a 17′ with a 115hp and very fuel efficient if we drive it nice. Our average over the last few years is 7 gallons/day. One of these years it will be my turn to supply the boat. I don’t want to buy one that is burning twice the fuel and requires an extra trip to town for more gas. Basically how big a boat and motor can I get away with.

In another note, if you are looking at a Merc, spring for the MercMonitor system.

It does all kinds of things. I don’t tow so I don’t use that feature. Link it to the GPS so the Smart Monitor will trade information with the GPS. This gives the smart gauge system the ability to see distance, speed, and time, combined with fuel flow gives you real time MPG info.
I also put an overlays on the HDS-8 to show a tach and trim level from the smart gauge system over the top of the depth finder.

It also includes troll control for the main motor.

Plus it gives you other motor information like hours and miles traveled. It is crazy how much info it gives you. I’m an analyst. I need info to make decisions.