Fuel Numbers for my "Speed Demon" (not) - Page 2

GetReel · #11 08-12-2003, 01:56 AM

Thanks for the math lesson, but the info was for inboard power.

Miles Offshore · #12 08-26-2003, 09:31 PM

Jeff, picked up my new nibral 16-16 4 blade today with no cup. 580 clams,shew. Anyways I hope to get her on soon and see what happens!!!!

GetReel · #13 08-28-2003, 01:22 AM

Miles: KEEP ME POSTED!!!!!!!!!!

omaier · #14 08-29-2003, 09:02 PM

Miles
I am very interested in how your performance changes with the new wheel!! Where were you able to find a 16" 4 blade?

Miles Offshore · #15 08-30-2003, 11:12 AM

Mike- Believe me I cannot wait either. My only concern is that I have the not so heavy version of 1.5-1 bw gear. I never really run over 3000/3200 rpms so Im not real worried,(but Ill find out for sure.) As far as the wheel goes you are right , they dont make a 16/16 4 blade yet but Michigan is supposed to start in the fall. I had to get a 17/17 and have it cut down and repitched. Murphys propellal in Norfolk did a real nice job using there CNC(?) . I know this is the computerized machine that they use on Navy surface ships and subs as well. They even provide the "stats" of the wheel when done. Anyways if you want their number let me know and I will get if for you but Im certain you want me to test mine before you dump the bucks into yours! [img]images/icons/grin.gif[/img] . A bronze will run around 100$ less than the nibral but will flex more when taking off,etc. Hope to get her on today since small craft flags are flying !!! You guys have a great and safe labor day weekend. craig

Miles Offshore · #16 08-30-2003, 07:01 PM

Got her on today and heres what happened. I had an annoying little whine between 700 and 900rpms. Any other speed it went away. Didnt have it before so I guess Ill have to figure it out. Anyways I love the new wheel already. At 3000 rpm's I was getting 22.5 knots burning 11.1 GPH. Much over that I didnt get a real good feel for yet but I did notice that the 4 barrel kicked in around 3500 and fuel consumption rose to 16 gph but I cant tell you what speed I was getting because I didnt have time to keep her up and running because of no wake zones inside. (didnt run her outside today. I dont think my speed increased significantly though to warrent running over say 3200. The real difference was in the ability to come to plane almost immediatly and she is very smooth and "strong". (feels like it has enough tourqe to be towboat us.) Anyways thats it for now. I guess my next thing is to figure out that whine. craig

GetReel · #17 09-24-2003, 05:32 PM

Craig: Any further research on the new prop?By the way, what type of shaft log are you using, traditional or dripless?

Miles Offshore · #18 10-14-2003, 09:44 PM

Hey Jeff, sorry I missed your last post. I have a traditional stuffing box. The propellar is giving me some heartburn now. I cant seem to get rid of the humm at around 800 rpm's Everywhere else is fine. It is currently 16-16 but I am going to have a little more pitch taken out of it to get my rpms up a tad. (Hopefully the noise will go away. I really dont believe its the cutlass bearing, have you noticed any such noise at low rpm's? The performance like you say though is outstanding and the torque is exceptional as well. Anyways I have to haul the boat again to pull the wheel. (also learned the hard way working under the boat while on a lift that a 3 bladed wheel puller doesnt work to well on a 4 blade wheel. ) I will let you know when I get it changed out again. Catch-em-up, Craig

GetReel · #19 10-15-2003, 01:08 AM

Craig just ran with new 17x16 four blade. I gained about 2.5 knots on the cruise and running at 3000 I was about 22.5/23 knots, @ 3200 she was movin @ 24.5 knots. My top end however was about 4000(31.5 knots) vs. 4400 (29.5 knots) on the old 16x17 3 blade. My hole shot is much better and low end performance has got more "grab". My temp didn't go up but I don't want to overload either so I may need to cut the wheel down to a 16x16, but I need to spend more time on it. I'm really interested to see what the fuel economy is...I also put on a new dripless shaft seal check it out at www.pyiinc.com , real slick.
Also new shaft, I had a groove in the old one. I only have one original mechanical part left on my boat [img]images/icons/shocked.gif[/img] and I'm sure thats next! Don Battin if you see this let me know your thoughts on the prop.

omaier · #20 10-23-2003, 09:11 PM

Jeff,
Is this a new prop for you? what was your thinking around going up in diameter and down in pitch? what reduction do you have in your transmission? Once you and Miles get this figured out I am going to take the plunge and buy a 4 blade Nibral prop. Thanks for the help!!