I'm trying to figure out the correct prop for my 1989 300 DA. It has twin 260 hp mercruiser I/O with 19" pitch aluminum props. It seems to be a bit over propped and I was considering trying 17" pitch stainless. Then I read a review in one of the boating magazines on this same boat/motor/year. They reported using 21" pitch props. I can't imagine trying to spin that if I'm not getting wot rpm with the 19" setup. If my tachs are close to accurate, I can only get about 4100 rpm. Any ideas? Can two of the same model boats with the same power and drives be that different?
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'89 300 DA Prop Pitch??
- Thread starter undertow
- Start date
I have an 89 30' with outdrives. The trick here is to get the original style prop. If you ask for a 14x19 they usually give you the latest version which has different shape blades. They have a lot of push at the low end but run terrible on a 30' I took them off in a day. I stick with alumnium because I would rather bend the prop than break the drive when hitting something.
Here's a link to the OEM prop chart from Sea Ray for the 1989 model year.
http://www.searay.com/boat_graphics/sea_ray_prop_charts/1989.ENGINE,DRIVE AND PROP MATRIX.pdf
As you'll see, the OEM prop spec was 14x19 as BoatPIB mentioned. There were many other configurations of engines and props. According to Sea Ray's specs for your set-up, you should be able to get 4600 RPM WOT.
Things you may want to check - the props (are you sure they are what you think they are, had 'em scanned recently?), boat load, engines, bottom condition, trim.
http://www.searay.com/boat_graphics/sea_ray_prop_charts/1989.ENGINE,DRIVE AND PROP MATRIX.pdf
As you'll see, the OEM prop spec was 14x19 as BoatPIB mentioned. There were many other configurations of engines and props. According to Sea Ray's specs for your set-up, you should be able to get 4600 RPM WOT.
Things you may want to check - the props (are you sure they are what you think they are, had 'em scanned recently?), boat load, engines, bottom condition, trim.
Undertow,
I used to own the same boat as you have. I switched to 18" pitch 4
blade props. I found that performance was better (much easier to get
up on plane) cruising speed was basically unchanged at same RPM and
fuel economy (if you can use that word for a boat) was a little better.
Regards,
Gary Shorrel SAMS SA
I used to own the same boat as you have. I switched to 18" pitch 4
blade props. I found that performance was better (much easier to get
up on plane) cruising speed was basically unchanged at same RPM and
fuel economy (if you can use that word for a boat) was a little better.
Regards,
Gary Shorrel SAMS SA