silver_power
Petty Officer 1st Class
- Joined
- Jul 8, 2009
- Messages
- 321
Hello again,...
after the first 50hrs of operation of my new 350mag mpi (cat), i still use the 19p aluminium prop.
The boat hits 56-58mph@gps and the engine reaches 4900-5050rpm depending load.
AM i crazy that i am trying to hit 60mph with aluminium prop?
?
With this prop, the boat can not trim up almost at all. The smartcraft trim gauge has 0-5-10 scale with the 5-straight position, and all i can trim is till 6 and nothing changes. After 7, the prop looses the thrust! Besides, the boat's handling is a lot worst that with 22p Enertia. This prop gives me the impression that because of the material, can not handle 300hp and can not push a boat to 60mph.
In the other hand, the 22P enertia hits again 56-58mph and 4400-4500rpm. But the handling i a lot better, and i can trim till the end 10 and the prop still pushes! According the service manual, using a big prop (overpitched) that does not allow the engine to reach the manufacture's wot 4800-5200rpm, has a result of performance lost and the engine operates with bigger load!
The prop selector of mercury site, giving the current performance with the current prop (22p) and with this engine (350 mag mpi cat) suggests 19-20p with 62,1mph@gps! I have three points....
Firstly, do you agree that it is out of question , useless, to talk about speeds of 60+mph and aluminium prop?...
Secondly, what prop do you thing i should use on my boat? 19,20,21p?
Third,...I already have an 21P Tempest that i used before 22ss Enertia, which i will test at the next days. Do you thing that this will go better that the 22p,.....i am just asking because Tempest has bigger diameter that Enertia and so bigger load, ...but lower pitch.....we willl see!!!It will be interesting to trying this! What do you thing??
after the first 50hrs of operation of my new 350mag mpi (cat), i still use the 19p aluminium prop.
The boat hits 56-58mph@gps and the engine reaches 4900-5050rpm depending load.
AM i crazy that i am trying to hit 60mph with aluminium prop?
?With this prop, the boat can not trim up almost at all. The smartcraft trim gauge has 0-5-10 scale with the 5-straight position, and all i can trim is till 6 and nothing changes. After 7, the prop looses the thrust! Besides, the boat's handling is a lot worst that with 22p Enertia. This prop gives me the impression that because of the material, can not handle 300hp and can not push a boat to 60mph.
In the other hand, the 22P enertia hits again 56-58mph and 4400-4500rpm. But the handling i a lot better, and i can trim till the end 10 and the prop still pushes! According the service manual, using a big prop (overpitched) that does not allow the engine to reach the manufacture's wot 4800-5200rpm, has a result of performance lost and the engine operates with bigger load!
The prop selector of mercury site, giving the current performance with the current prop (22p) and with this engine (350 mag mpi cat) suggests 19-20p with 62,1mph@gps! I have three points....
Firstly, do you agree that it is out of question , useless, to talk about speeds of 60+mph and aluminium prop?...
Secondly, what prop do you thing i should use on my boat? 19,20,21p?
Third,...I already have an 21P Tempest that i used before 22ss Enertia, which i will test at the next days. Do you thing that this will go better that the 22p,.....i am just asking because Tempest has bigger diameter that Enertia and so bigger load, ...but lower pitch.....we willl see!!!It will be interesting to trying this! What do you thing??
