3300 Open Props

[Lucky Dog 33]

Recently picked up a 3300 Open with twin original Crusader 454s. The props that came with the boat are 17x20 3 blades. The boat can’t get out of its own way at a reasonable cruise of 3200-3400rpm. At 3200, the boat barely gets 16kts and even with full trim the bow is in the air.

Tiara sent me the original performance sheet for this set up, 350hp 454s with 1.88:1 transmissions and 18x21 3 blade props. At 3000rpm the boat should do 26mph. Granted, this is not a brand new boat and original notes, so I know that is not realistic, but 16kts????

A local mechanic, as well as prop shop told me I should run 19x19 3 blades, which should get me to about 20kts at 3000-3200. This sounds more like what the boat should run. My concern is the distance from the prop blade to the hull. 

Has/is anyone running 19” props on a 3300? Or does anyone know the distance from the shaft to the hull at the props? 

Thanks in advance. I plan to order props and have everything on hand before I get a short haul.

[Misdirection]

Tiara builds really great boats. I'd suggest reinstalling what it left the factory with.

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[emarrero]

Have you spoken with S&S over in College Point? http://sspropeller.com/

[Lucky Dog 33]

S&S is the local shop. My concern is clearance between prop blade and hull.

[ardoski14]

My 1988 has 18 x 21 Ni-Bral. Feel it is propped correctly. It does need some tabs when fully loaded and does have generator also. Think 3100 rpm  I'm doing about 24  to 25 mph. Hope this helps

[Lucky Dog 33]

Thanks for the info. I too have the generator mounted centerline near the transom. What are you able to spin WOT with 18x21s?

[Lucky Dog 33]

Update: I pulled boat today and swapped props out with 19x20 3 blades at the recommendation of my local shop. Turns out the props I pulled off are stamped 18x21s, but they are def not 18” diameter. 

It was extremely choppy today in the LI Sound with east wind 15-20. Seas were 3-4s tight. Couldn’t really test out the new props as I wanted. Was able to get 20-21kts at 3200-3300rpm and e bow is definitely down more.  Need a calmer day to put them on the pins to see what she spins up to.