props speed limites

**Dave S** · 09-11-2018, 05:28 PM

Chaz.... Ya gotta be the best to nkowww durmklang....Thanks D....

**Coupe427** · 09-11-2018, 08:51 PM

You must be from around here cuz I understand every bit. Lol must be Ol Rex rubbing off.

Can the 1.5 out of an inboard lower be used in a sporty?

**Dave S** · 09-11-2018, 08:56 PM

If the front bearing is the same.... Getting into cross use with out P # is the thing....

**Dave S** · 09-11-2018, 09:12 PM

The I os get the ratio in the upper case your limited to at best a 3.4 case ratio....I am not worthy till I pull one apart....I like Part# cross ref but not sure of stuff till I see....

**home made tunnel** · 09-11-2018, 09:22 PM

Originally Posted by Dave S

Ya just punch DRUNK......HeeHee

Posted at 2:44pm. Gotta love day-drinking on a Tuesday!

**Dave S** · 09-11-2018, 09:25 PM

Dammm I just keeping.....I ran out of Vodka ,... Now Rummmm.

**Dave S** · 09-12-2018, 05:24 AM

The world bout ta be upside downnn get ready.,,,,wind rain

**Dave S** · 09-12-2018, 05:26 AM

All week long.....drunk.......sorry wife.....

**OLEGATOR** · 09-14-2018, 11:09 AM

Originally Posted by Dave S

peps looking for 34 pitch props....need to up gear? Prop tip limites? Anyone?

when I first started working on props, (1959) there was a lot of talk about tip speed/boat speed. as time went on, not so much. I got to meet a few prop experts and noticed they all carried a slide rule in their shirt pockets. I got me one and learned the basics. I did figure out there was some correlation, but being hardheaded, I decided to just make a change and see if it was what worked or didn't. this rambling is not what you wanted to hear but wanted you to know someone other than you was aware of the issue of prop/tipspeed/boatspeed. by the way, I never did get smart enough for a smart phone either.

**rude tim** · 09-15-2018, 11:27 AM

Prop tip speed is an interesting subject. On OB’s and IO’s they seem to gear down the prop speed but on V Drives they tend to over drive props. If I am not mistaken the TFH’s spin the props around 20,000 rpm! This leads me to think it comes down to horse power and torque along with being able to shift gears or not.

**Risco** · 09-15-2018, 04:24 PM

Originally Posted by rude tim

Prop tip speed is an interesting subject. On OB’s and IO’s they seem to gear down the prop speed but on V Drives they tend to over drive props. If I am not mistaken the TFH’s spin the props around 20,000 rpm! This leads me to think it comes down to horse power and torque along with being able to shift gears or not.

V drives are not surfaced propellers might also have something to do with it