How much power

edcordes

Recruit
Joined
Mar 6, 2001
Messages
1
I am looking at buying an 18 foot bass/ski boat (Procraft)and am confused a little about power needs. I'm interested in hole shot for skiers, not top end. I'm told by salesman that 150 has as much hole shot as 175 or 200, in the Mercury EFI line. I boat at altitude, 5,000 feet to 9,000 feet, and have a few big friends. Can anyone help with advice?
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: How much power

Exactly! The prop is the key. The prop, balance, bottom design and the x dimention is what makes it happen or makes it a nightmare. I built a 150 for a friend's Procraft 3 or 4 years ago and was really suprised how well it ran. It was a bass boat model and it had a lighting hole shot and ran in the mid to upper 70's. Besides, the easiest thing on the motor is two props. After all -- you need a spare anyway. Good luck!
 

ODDD1

Lieutenant Junior Grade
Joined
Jan 23, 2001
Messages
1,054
Re: How much power

Ed, whenever your boat shoppin, an this question arises, take a look at the BIA rating tag inside of boat[ is usually yellow an black] it will have a max horsepower rating on it for that boat....stay as close as you can to that number..the boat will perform well for you and it'll help on resale value down the road. as far as one of these motors having a better holeshot than another....baloney....correct choice of props will help more than anything else.
 

TJ

Recruit
Joined
Mar 23, 2001
Messages
2
Re: How much power

I own an 18'4" Champion fish & ski (bass boat), and used to go skiing a lot, with a lot of people in boat (7 people or 900 pound). It had a 175 carb Merc and now has a 1997 Merc 175EFI on it. I have dragged all sizes of people behind that boat with 3 blade props, never had any complaints. I have a 3 blade, 25 Tempest on it now, and pull average size skiers up ok (170 pounds). If those friends are big, might go with 4 blades and less pitch than I have. I would suggest you get the boat on water and ride with dealer mechanic and have him prop it out for you.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: How much power

I can't add anything about selection of the motor except: To tow two skiers you will need about 5 to 6 hp per 100 pounds of boat, fully loaded and fueled. If that exceeds the boats power rating don't buy it. It will probably come to 70% to 80% of the rating. The only reliable way to select a prop is to put it on the boat, again fully loaded, with one or two skiers behind and run it to full throttle. The engine should reach, but not exceed its rated speed range. On most motors that is between 5,000 and 6,000 rpm. For other recreation not including skiers you will want a second prop with 1 or 2 inches more pitch. Four blade props give a good hole shot, but very rarely perform as well as three blades of the same pitch because of the added drag. A three blade, cupped stainless steel prop should do anything you want from a good boat with a good engine. Good Luck.
 
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