QC
Supreme Mariner
- Joined
- Mar 22, 2005
- Messages
- 22,783
Re: WOT on 4.3 merc
No, the relationship between diameter and pitch is complex, and often misunderstood. Generally speaking you should ignore it. However, larger, slower boats typically do well with larger diameter wheels to handle the load. This is what the Bravo 2 was primarily about prior to Bravo 3 introduction.
You need to confirm your data!! There is absolutely something amiss. Either the gear ratio, pitch, speed or RPM is wrong. Maybe more than one . . . Making any decisions before these things are clear is stupid unless somebody can loan you props. Still won't mean a lot because you won't know what data is off with the "test" wheels.
Personally . . . I still think tachs and here's why. 39 MPH from 380 total hp (still unconfirmed as well) is actually pretty dang good. Especially with a loaded boat, and I am guessing you had people and stuff and fuel and water and people and ice and beer and tools and stuff that wasn't on any test boats. This boat at 39 MPH and only 4000 RPM IMHO would not plane. Basically, if the data was right, she would be too high geared (prop + gear ratio), or running too poorly to plane. The 39 MPH tells me they're making power. But if the 4000 RPM was right you'd be here complaining that she wouldn't plane, not about top speed.
No, the relationship between diameter and pitch is complex, and often misunderstood. Generally speaking you should ignore it. However, larger, slower boats typically do well with larger diameter wheels to handle the load. This is what the Bravo 2 was primarily about prior to Bravo 3 introduction.
You need to confirm your data!! There is absolutely something amiss. Either the gear ratio, pitch, speed or RPM is wrong. Maybe more than one . . . Making any decisions before these things are clear is stupid unless somebody can loan you props. Still won't mean a lot because you won't know what data is off with the "test" wheels.
Personally . . . I still think tachs and here's why. 39 MPH from 380 total hp (still unconfirmed as well) is actually pretty dang good. Especially with a loaded boat, and I am guessing you had people and stuff and fuel and water and people and ice and beer and tools and stuff that wasn't on any test boats. This boat at 39 MPH and only 4000 RPM IMHO would not plane. Basically, if the data was right, she would be too high geared (prop + gear ratio), or running too poorly to plane. The 39 MPH tells me they're making power. But if the 4000 RPM was right you'd be here complaining that she wouldn't plane, not about top speed.
