23 Sceptre OB on transom vs 23 CC with OB on bracket - impressions.

[Fr. Frank]

Originally Posted by gofastsandman

Big Shrimpin` suggested I try a Mirage + so I found a 15.380x17p.

Denny and I tested many props shortly thereafter. Apollo 4 bl 14.75 x 20,
PT ofs 4 bl 15x15, and the Mirage +, were among the standouts.

76 Red suggested a SST 1 3bl many moons ago. I shrugged this off as not being
serious at all. I now run a 15x16p and can hold plane at 2700 rpm easily.
12 mph all day. I wonder if this is part of the 2 stroke factory exhaust design.

I get ya' Sandy. On my previous Seafari, I started with a 4B 16P over-hub cleaver on a B&B'd XR Merc (prop came with motor). Motor had big 4.75" gearcase, 1.65 gear ratio with a nose-cone and low water pickup. Top speed was about 44 kts (not mph) at 6100 rpm, but fell off plane below 16kts, and very poor holeshot. No trim tabs (Threw a hell of a rooster tail above 40, though).

I switched to a 3B Mirage 17P. Top speed was 42 knots, would hold plane down to about 13 kts and got on plane very quickly.

Got a chance to talk with the guys at PowerTech and bought an OFS 4B 15.5x15P. 1 knot slower than the Mirage, but even better holeshot, much better low-speed control and would hold plane down to 10 kts. Max RPM fell to 5650.

After a couple of months and lots of emails, I traded that back to PT for a one-off custom-built (read non-returnable) Power Tech OFS 3B 15.25Dx16.5P with extended tip cupping because I ran with my motor mount as high as possible. Top speed was now 46 knots at 6050 rpms with light fuel and one person on a cold day. When I put the bimini up and loaded the family top speed was about 42-44 kts, depending on conditions. Time to plane about the same as the Mirage, and would hold plane down to 11 kts in calm water. Ran best in a light chop.
Man, I LOVED that prop!

Swapped the Merc XR motor for a 90hp Opti in '06. Top speed fell to 34kts, but fuel economy went from 1.9 NMPG, to almost 6 NMPG average. Partly because I wasn't tempted to run at 5800-6000 rpms all the time.

[MASBAS]

Snookerd, Regarding point #2, which was better? Can you give me some more details on that (without upsetting anyone). I am currently planning a 23SF resto, bracket with twins is the current plan. I have read a ton on this site but have not yet taken a ride on one.

I need to find someone in NJ with a 23sf and bracket with twins.

Thanks

[Snookerd]

Originally Posted by MASBAS

Snookerd, Regarding point #2, which was better? Can you give me some more details on that (without upsetting anyone). I am currently planning a 23SF resto, bracket with twins is the current plan. I have read a ton on this site but have not yet taken a ride on one.

I need to find someone in NJ with a 23sf and bracket with twins.

Thanks

I ran twin Mercury 225s on an Armstrong bracket on a 23SF. Each motor was 445lbs. If you look at the two pictures I posted earlier in the thread, the key is to look at how each motor is trimmed. The transom mounted motor is positively trimmed and the bracketed motor is negatively trimmed. That’s a giveaway for balancing the ride. The famous Woosh of our VDRs will always be there with either set up. It all depends on how much weight forward is set up on the bracketed boat. Twins on a bracket can be great, if you look at this past week‘s Florida sportsman dreamboat addition, Coreys Sceptre to center console conversion with twin 150 Suzuki’s on a bracket look like it rode pretty well. It’s doable, but for me personally a large single motor is the maximum amount of weight I want on a 23SF SeaCraft. Transom mounted or on a bracket- twin 115‘s or the now canceled three cylinder G2 Etecs up to 150 hp would be fine on a Sceptre due to the offsetting weight of the cabin so far forward, but I probably wouldn’t do that on the SF.

[gofastsandman]

Originally Posted by Fr. Frank

I get ya' Sandy. On my previous Seafari, I started with a 4B 16P over-hub cleaver on a B&B'd XR Merc (prop came with motor). Motor had big 4.75" gearcase, 1.65 gear ratio with a nose-cone and low water pickup. Top speed was about 44 kts (not mph) at 6100 rpm, but fell off plane below 16kts, and very poor holeshot. No trim tabs (Threw a hell of a rooster tail above 40, though).

I switched to a 3B Mirage 17P. Top speed was 42 knots, would hold plane down to about 13 kts and got on plane very quickly.

Got a chance to talk with the guys at PowerTech and bought an OFS 4B 15.5x15P. 1 knot slower than the Mirage, but even better holeshot, much better low-speed control and would hold plane down to 10 kts. Max RPM fell to 5650.

After a couple of months and lots of emails, I traded that back to PT for a one-off custom-built (read non-returnable) Power Tech OFS 3B 15.25Dx16.5P with extended tip cupping because I ran with my motor mount as high as possible. Top speed was now 46 knots at 6050 rpms with light fuel and one person on a cold day. When I put the bimini up and loaded the family top speed was about 42-44 kts, depending on conditions. Time to plane about the same as the Mirage, and would hold plane down to 11 kts in calm water. Ran best in a light chop.
Man, I LOVED that prop!

Swapped the Merc XR motor for a 90hp Opti in '06. Top speed fell to 34kts, but fuel economy went from 1.9 NMPG, to almost 6 NMPG average. Partly because I wasn't tempted to run at 5800-6000 rpms all the time.

I'd like to see the Cyclone 4 bl against the Bravo 4 bl.

[bmajvi]

It's probably obvious, but thought I'd throw in that in addition to the difference in balance point between the Sceptre hull and a CC that Snookerd mentioned, the "moveable ballast" - people and gear - are typically also further forward while underway in a Sceptre than a CC. People at the helm, and junk in the trunk. We get on plane very easily and quickly, running just a Merc 150 4 stroke on an old non-floatation Armstrong bracket. I haven't tried to pin down exactly how slow it will maintain plane - fixing the trim tabs hasn't made it to the top of the list yet.

[kmoose]

Twins on a SF with a bracket would worry me with stock deck heights.