Help settle an argument?

[NW Redneck]

I was having a 'discussion' with my father in law on the weekend about waterskiing and boat/engine size. He has an 18' runabout style (early '80's?) v-hull boat with an early '90's 90hp yammy o/b. He was stating (quite vehemently!) that this setup was not enough power to pull a skier without doing damage to the motor. "Nothing will kill the motor quicker. It's just not enough power for this size boat." All this time I'm looking out onto the lake and watching a 12-14'-ish whaler-style boat with with an older MAYBE 40hp o/b pulling skiiers and wakeboarders with no problem getting them up. So, does his argument 'hold water'?

 

[Utahboatnut]

Re: Help settle an argument?

Not that this would settle your argument but that should be fine to pull skiers with, for sure wakeboarders. An inexperienced slalom skier may struggle getting up but thats about it. He may be killing it already depending on what prop he is running, if incorrect it will not let the motor run at the correct rpm range which is way harder on them than anything. Heat(or too much of it) and carbon buildup is what kills outboards in my opinion. My last boat 20' wellcraft cuddy had a 200 horse evinrude 1980 model year and that boat was a beast. It would pull slalom skiers out no problem and could run 40mph+ and god only knows how many hours that thing had on it.

 

[skibrain]

Re: Help settle an argument?

As long as the waterpump is working correctly (cooling) the oil injection system ok (lubrication) and the prop set up not letting prolonged rpm at above recommended rpm range (over-revving). Pulling skiers will not damage a boat at all.

It could be that this boat would more optimal for skiing if it had a larger motor (many 18' boats are rated for 125 or even 150 max. hp). If it is a heavy hull, hole shot performance may not be great, but that is only a frustration for the skier. Does not hurt the motor.

it is not like towing a travel trailer through the mountains with an under-powered rig. There is no transmission to overheat and burn out. No direct link to the engine making the engine lug. The prop just slips.

BTW I've done lots of skiing behind a 13' Whaler with a 40 hp. A GREAT ski boat for smaller skiers!

 

[kenmyfam]

Re: Help settle an argument?

Should be no issue if set up is good.

 

[Les Robb]

Re: Help settle an argument?

We used to ski with a starcraft 14-15 and 35hp Johnson. Yeah tough to get up but what the heck. You really think your going to win this argument.

Good luck

 

[jay_merrill]

Re: Help settle an argument?

Don't think in terms of pulling a skier. Simplify the issue and think of in terms of load being placed on the engine.

A light 18' hull that is typically operated with very little "payload," would do just fine with 90hp on the back. Conversely, a heavy 18' hull, typically loaded down with lots of people and "stuff," might not do so well.

For both these boats, however, prop selection is the key issue. Keep the engine in its targeted WOT range, no matter what it is that you use it for, and you'll have a happy motor. Use a prop that is too steep in pitch and you'll have an unhappy motor that will probably not live up to its longevity potential. Remember, also, that if the motor truly is too small for the boat, you may get to a point where installation of successively smaller pitch numbers don't help anymore, because you are either still lugging the engine or just can't get the boat to go fast enough to make skiing much fun.

As for your FIL's boat, if he is running about a 19" pitch prop on it, my guess is that he could drop down in pitch to a point where he could pull a skier without hurting anything. If he is running something on the order of a 15" pitch prop now, I would have to agree that he doesn't have much room to pull a skier. I say that merely because dropping down to a 13" pitch prop is only going to push his boat at about 20 mph and that's most likely without a skier.

 

[highN'dry]

Re: Help settle an argument?

Correctly propped it would pull skiers just fine, he just does not want to.

 

[lowkee]

Re: Help settle an argument?

As others have said, the prop makes the difference. You could pull a tugboat witht gat with a prop matching the load. If the engine has lower than optimal RPM now, a skier would make things worse, but if a lower pitch prop is used, as long as the skier can get up, it can pull one.

 

[tashasdaddy]

Re: Help settle an argument?

we skied with a 14' 3/8 plywood, home made boat, with a 1955 15 hp evinrude, tiller.

 

[robert graham]

Re: Help settle an argument?

mine is an 18' jon boat with a 90HP Yamaha and it has plenty of power to pull skis or tubes or another boat, in an emergency. lack of power should be no real issue for your father-in-law's boat, with the right prop and if the motor is well maintained. of course, arguing with him may be a losing proposition for you. Good Luck!

 

[rndn]

Re: Help settle an argument?

Is it correct to assume it's your father-in-laws boat and you're trying to get him to allow you to water ski behind it??
If you're FIL thinks that it will hurt his boat and doesn't want to do it do you really want to hear in 10 years when something breaks on his motor that it was all because you used it for water skiing?