94sylvan

Looking to pick up some different props to try next season. Currently running 21 mirage, 21 Solas Titan HR3, and a 23 Tempest Plus that has increased cup. Boat is 21', 20 deg. deadrise, 8" pad at rear, a little over 3500# operating weight, alpha drive w/ sternjack and a 470ish HP sbc. Drive is deep (7.5" prop shaft depth below pad) I damaged my lower that had a nosecone mid-season last year and lost about 3 mph with a std. lower the rest of the season. A Mirage 21 with std. lower runs 69mph @ 6100rpm but will blow out with any chop, or additional positive trim. Did not do this with a nosecone. The Tempest provided great lift, but was too big diameter / pitch and couldn't swing it to where engine needs to be. I never ran the tempest with a nosecone. I also didn't run the Solas after the lower unit damage, but it has more cup and similar rake to a mirage so I would assume similar / slightly better than the 69 mph the mirage achieved. I've read on another forum about smaller alpha boats seeing significant top speed increases going from Mirage to Turbo or Laser 2 props, but trading off cruising efficiency. Wondering if this boat is too heavy and / or long for similar gains? If a laser II would work, where should I start as far as pitch? 23-24?

SB

iTrader: (1)

Boat dependent I think. What else is new, right ? Lol.
My 21” Laser II makes my boat ride horribly. It just slaps the water over waves, even trimming down. Irritating as fuk. I’ve never seen anyone say the same. So again, probably how it works on this one.
The normal complaint people would have sith the Laser II was when turning harder they’d cavitate, if I remember right,

Turbo prop works good on my uncles stock 350/260hp Scarab I. It lifts my boat right out of the water. Drive stays same position, boat trims. Lol. I have not tried it with Aloha SS though. I should.

Mine blew out all props at 65mph. Nose cone let it get to 68. Alpha SS 73.

94sylvan

SB,
Your boat has always been a** heavy so this would make sense with the high rake angle of the laser. Mine tends to be a little bow heavy as it responds well to bow lifting props and the sternjack really helped. Just curious if there's enough blade surface to carry this boat with the laser. Looks like snow coming your way this weekend - sleds ready?

SB

iTrader: (1)

Yup, ready, but ground isn’t frozen enough.Normal this time of year.

Laser II is one of those props, though, it seems, every smaller boat with alfalfa.drive needs to try to see what boat wants.

JaniH

Every hull is different, My 22ft chris craft/alpha liked 4 blades, the rev4 and bravo 1, bravo 1 being the best. from the 3 blades i tested, the tempest plus was superior comapared to other 3 blades, amazing grip for 3 blade prop. MIrage plus was the worst, even with added cupping, it was horrible! absolutely no grip. never tried Laser. My propshaft was at 5.3", so not a good comparison to your compo.

El Espanol

I can give you some opinions from the waters we ride in Europe and the different set-up.

first, when we read the treads about 20ft boats running 80MPH on a pad we got crazy, because we never saw that here!

About the Laser II its quite a very good prop with nice price/development relation. The blades are not very thin, then they are reliables.

They are ventilated props, soo is one step forward in performance.

I have seen them running very well in light boats under 23ft, and not very powerful 2 stroke outboards.

You can run a 18ft, 115HP with a 21” laser over 40MPH easy.

if you have a bit more power, and nosecones, you can run 25” at +60MPH with longer gear relation.

But if you have an V6, then I would move Ballistic. You will find faster response and top end with a couped design.

Javier.