what prop for skiing & tubing

[medic181075]

I am fairly new to the stern-drive boating world. I need a bit of help deciding on a prop, as the one that came with my boat is pretty beat up. 89 SunRunner 175b (17.5'), Volvo Penta AQ131D/275 (120 hp/2.15:1) with the top RPM rating at 4600-5000 according to the volvo chart. I have found a chart from volvo which tells me top speed for different props with my I/O setup, but none of them tell me what I need to know. While I am somewhat interested in cruising, the boat will be on a small lake most of the time with the main use being for tubing & skiing. Common sense tells me that a bigger prop will get me up out of the water quicker and be better for everything. I was thinking of a 14x21 or 15x19 as these are the largest props that volvo recommends for my setup. Any thoughts or advise would be greatly appreciated.

 

[chris0061]

Re: what prop for skiing & tubing

The smaller the pitch the more whole shot for pulling up skiers. To prop your boat right you need a tack, a speedo, and a normal load. You want your wot rpm to the high side of the spread and I would recommend stainless over alum and cupped would help. You do need to find your wot rpm with the speed to start with then you can go from there. I'm no expert but the guys on here helped me prop my boat right and it makes all the difference in the world. with your gear ratio and a 19 pitch prop and you can hit 5000 rpm with it your speed would be 42 mph. It probably wouldn't be quite that cause of prop slip but within a few mph. I would definitely not go with the 21 pitch. start with the 19 and you may have to go down to 17.

 

[erlindbl]

Re: what prop for skiing & tubing

I agree with the above and would add if your on a small lake where top end isn't going to mean a whole lot, I would go with the 17P. You will thank yourself when your not dragging half the lake to get up. If your doing any kind of water sports with the boat, tubing, skiing etc, you will be happier with the 17P prop.