My 23

[ripndip]

Fr. Frank,

My apologies again. NOW you can say you have seen them turned in TWICE.




Hope your smiling cause I'm giggling. It was the NEVER that got me.

Skyler

[Fr. Frank]

NOW you can say you have seen them turned in TWICE.

Okay. I have seen them turned in twice.

Seriously, I was part of the team that did the factory prop setups for Mercruiser sterndrive and Mercury and Yamaha outboard powered Wellcraft Scarab and Excaliber offshore boats in the mid-late 80's. While we discussed inward rotation, we decided against it because of the "P" factor. As I recall, some slide-rule engineer calculated a 3-4% loss of thrust from submerged inward rotation, a loss not present with surface-piercing propellers and running semi-submerged.

Which, by the way, is why the standard twin engine setup for the 27' Wellcraft Nova II and 26' Wellcraft Antigua back '86 to '89 was Mercruiser 350/260's with two RH Alpha drives. Counter-rotation was offered as an option. Best performance and the standard factory setup was with twin RH 23"P surface-piercing thru-hub Cleavers, so rotational direction/ "P" factor wasn't really a issue. With CR drives, we used outward rotating ventilated Mirage propellers.

I will say this, I have seen CR props installed by a dockhand onto the wrong lower units on twin Zuke 250's after 100hr service. That was just two weeks ago. The owner shoved the controls forward and promptly backed into into the dock, cracking both cowlings.
Needless the say, the Marina owner wasn't happy about having to give the guy new cowlings. On the other hand, you should never put your boat in gear and throttle up at the same time right at the dock, without clearing the dock and other boats first.

[peterb]

The owner shoved the controls forward and promptly backed into into the dock

Father Frank,

So, are you saying that I will need to look into a rearview mirror to drive forward?

[Fr. Frank]

Father Frank,

So, are you saying that I will need to look into a rearview mirror to drive forward?

Don't tell me you drive your boat around bass ackwards too!

[ripndip]

I'm glad to see you have a sense of humor. It's almost impossible to exist these days without one.

One of my clients has three boats, a 65 Buddy Davis, a 35 Cigarette, and a 26 Regulator. The Cigarette is a classic, and he just put new engines in. He listened to the guy who sold him the engines on the original set of props, and was unhappy with the ride and speed of the boat- it wanted to porpoise and wasn't any faster when he increased horsepower by 100 a side. I suggested trying a different set of props for the ride, and also suggested he could try spinning the props in. He has tried several sets of props since then, and was instantly pleased with the first set/smaller diameter/more pitch which I switched and then seatrialed with/for him. He has since switched the drives and turned the props in and has picked up speed and ride and is now looking for an even higher pitch set of props.

Because of this result, he is now going to try spinning the props in on the '08 26 Regulator. It is another heavy center console deep V boat. I will let you know the results when he tells me.

I spoke with Ken? from Prop Gods regarding spinning props inward, and he agreed that it can yield positive results in some applications. He told me of a boat he tried it on-27 Fountain with very bad results. I guess with the "reliefs" in the bottom of the boat combined with the props spinning in he was unable to get the boat on plane and immediately switched them back. I have also heard of a few people trying to do it with Contenders. Not good results with those. Not really a surprise as the 23' Contender has the exact same length and width as a 23 Seacraft with more (23 degrees) deadrise and weighs 800 lbs. less. They are light boats that don't do well with stern lift, and IMO don't do well anyway!

It is just impossible to say what will happen until you try.

[Fr. Frank]

Ken? from Prop Gods regarding spinning props inward, and he agreed that it can yield positive results in some applications. ...
It is just impossible to say what will happen until you try.

I'm old school, and have been out of the high performance field for almost 20 years. I never tried spinning inwards, I just believed the engineers who told us why it was a bad idea. I do know that with that Rybo Runner we switched the lower units on, we pick up quite a bit of performance by changing over to spinning outwards. But a Rybo Runner also had a 10' beam, with the motors mounted a full 4' apart, center to center.