Fuel Numbers for my "Speed Demon" (not)
 

Have been playing with my new navman and gotten some interesting results for you inboard guys if you like. 350 magnum 270 hp PCM inboard and I am currently turning an old ,tired 17"/15 pitch wheel-with the following results- 3000 rpm's 20 knots at 9.5 to 10 gallons an hour. 3200 rpm's 22 knots at 12-12.5 gallons an hour. 3800 rpms 25 to 27 knots at 20 gallons an hour. Funny how my new tach only reads WOT at 3800. The old tach read 4200 rpms. Boat tachs have always IMO been P.O.S.
The 17/15 is not real efficient but is a great trolling wheel because I can troll real slow during rockfish season. I believe a 16"/17 pitch is what originally came on the boat. I am going to reprop it soon and am still debateing on the 16"/17 pitch 3 blade or a 16/16 4 blade both cupped.I think both my economy and speed will increase preety much although that slow trolling speed will be gone. Most of my rockfishing anyways is from November into february so I can change the wheel if need be.

I support the "BIG FISH CATCH AND RELEASE THEORY"

craig

Re: Fuel Numbers for my "Speed Demon" (not)
 

Miles - drag a bucket or a board of the stern, will slow you down from the fast troll...

Re: Fuel Numbers for my "Speed Demon" (not)
 

<font size="2" face="Verdana, Helvetica, sans-serif">Amen, brother.

Re: Fuel Numbers for my "Speed Demon" (not)
 

Miles... I'd get a good Tach before I'd start playing with wheels. I have a good number of years messing with inboard boats. But it's your choice if you beleive me or not.. But your not turning up to max RPM's (if the new tach is right)with the 17/15 wheel. 1 inch of Diam is 1000 RPMS and 1" of pitch is 500 rpm's. Your at 3800 with the 17/15, knock 1" of Diam. off and your up to 4800 that's about 200 over max for your motor, so add a little cup and it should be just right. The 16/17 is allmost the same wheel, just at lower rpms(idle speed)your gonna move faster. I'd look at a 16/15 with a cup, A case of beer says I hit it right on the money [img]images/icons/shocked.gif[/img]

Re: Fuel Numbers for my "Speed Demon" (not)
 

Thanx Don,I appreciate the advice. Im going to put one of those timing gun tachs on it and see where its at. I really think the old tach was right and the new one isnt. She seems to be turning up real well, and btw I drink Bud or Corona's. [img]images/icons/cool.gif[/img]

Re: Fuel Numbers for my "Speed Demon" (not)
 

Miles.. Sounds like a good plan..but if the new tach is wrong all bets are off.. [img]images/icons/tongue.gif[/img] .. Your close with the old tach, I'd just have the wheel worked and it just may turn up.. But Corona's it will be.. cuz themz Budz give me a killer head ache.. But on another note..hows the tuna fishing been off shore, any size yet?.. I see that the VA.Beach bouy has some nice water temps. I'm planing to start running to the Dog soon..

Re: Fuel Numbers for my "Speed Demon" (not)
 

Hey Don, yellowfins are just starting to show up good here, they have been very hot just south of here from the triple zeroes down to the point. Most have their limits and are done by noon. The fish have been running smaller than normal so far on average 25-35 lbs although the larger 65 lb fish are becoming more frequent. The water temps are rising quickly, I have heard of fish being caught at Norfolk Canyon a couple of weeks ago so I would imagine that they are already up there by now. There have also been some bluefins caught inshore but not many folks are targeting them. Since my last back operation my tuna days are over but my bro-in -law just purchased a 43 viking so I can probably be coaxed into a couple of marlin trips [img]images/icons/wink.gif[/img] go get um-craig

Re: Fuel Numbers for my "Speed Demon" (not)
 

Miles: I know we've discussed this before and I'm turning a 16x17 which I think is the original setup. I achieve the same as a friend with same prop at 23k@ 3200ish, 25k@3600ish and 29K@4000ish. I troll wire line for stripers and its plenty slow enough. Thanks for the fuel consumption info. Keep me posted though on the results when you change. Don I'll meet you at the 19 Fathom Lump! (Hot Dog too far south).

Re: Fuel Numbers for my "Speed Demon" (not)
 

Fuel comsumption update for the Inboard crowd. Just ran from Sandy Hook to Little Egg Inlet,NJ. Its about 65 miles per my GPS.I burned one full tank, 48 Gals., +/-, averaging 3250 RPM, 22 NMH and arrived in 3 hours.

Re: Fuel Numbers for my "Speed Demon" (not)
 

OUCH! Jeff that is worse fuel mileage than my old 225 Johnson. 45gal's for 65 miles nets you only a 1.4 average. My dual 115 4 stroke Suzuki's would have done about 2.8-3.2mpg, and I could have done it at 30kts without breaking a sweat. Those old inboards do look good though!

Re: Fuel Numbers for my "Speed Demon" (not)
 

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

Re: Fuel Numbers for my "Speed Demon" (not)
 

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!!!!

Re: Fuel Numbers for my "Speed Demon" (not)
 

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

Re: Fuel Numbers for my "Speed Demon" (not)
 

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

Re: Fuel Numbers for my "Speed Demon" (not)
 

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

Re: Fuel Numbers for my "Speed Demon" (not)
 

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

Re: Fuel Numbers for my "Speed Demon" (not)
 

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

Re: Fuel Numbers for my "Speed Demon" (not)
 

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

Re: Fuel Numbers for my "Speed Demon" (not)
 

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.

Re: Fuel Numbers for my "Speed Demon" (not)
 

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!!

Re: Fuel Numbers for my "Speed Demon" (not)
 

Pulled the 4 blade and reinstalled the 3 blade while I play/prop shop plays with the 4 some more. Humm is completely gone with the 3. We will see, I know the water is starting to get [img]images/icons/shocked.gif[/img] cold )60( changing these wheels under the boat lift. Damn near fell in today. [img]images/icons/rolleyes.gif[/img]

Re: Fuel Numbers for my "Speed Demon" (not)
 

Mike, it's a new prop for me, my 16x17 3 blade was really dinged up. The smallest 4 blade available is 17, so I went to 16 pitch. UPDATE: after running several times I think the prop needs to be cut down to 16x16. The 17 prop is "loud" and I think its too tight to the prop pockett and I've also picked up a little too much speed for the slow troll with wire line. The hole shot is great. I'm 1.5 gears if I recall. I'll keep you posted but I'd hold off on the Nibral until we get this right.

Re: Fuel Numbers for my "Speed Demon" (not)
 

Jeff, Mike- I'm now going to a 16-15, after putting her on the software that the prop shop runs this is what shows to be optimal. I guess we will see. craig

Re: Fuel Numbers for my "Speed Demon" (not)
 

Just wanted to share my setup. I checked my prop shop papers and found mine is a 15" x 17.5 pitch. Good hole shot and run plenty quick, 3200 rpm nets 24 knots @ 10 gph.

Re: Fuel Numbers for my "Speed Demon" (not)
 

Skip, thanks for info, are you 3 or 4 blade?

Re: Fuel Numbers for my "Speed Demon" (not)
 

Don, I was hoping you were just ignoring my dumb @ss,lol.Right on the money were you . I am guessing with as crappy a weather we have been having instaead of fishing another boat I might get her changed the weekend . I have learned something though. It doesnt matter how frequently you change your wheel,it is still a son of a beetch to get off every time. Coors light ,huh??? No problemo, you can pick em up when you come down and go rockfishin with me this winter. Big boyz are just starting to show up. Offshore has been hot when mother nature allows anyone to get out.(White Marlin that is.)see-ya-craig

Re: Fuel Numbers for my "Speed Demon" (not)
 

Hey guys.. I just pick back up on this post today.. Miles..., [img]images/icons/shocked.gif[/img] Make that case of beer Coor's Light long necks bottles. please. It's looking like your gonna be at 16x15 when you done.. Right where I thought.. [img]images/icons/tongue.gif[/img] lol .. Jeff you wheel sounds a bit to fat right now, did you get the pitch out of it yet?

Re: Fuel Numbers for my "Speed Demon" (not)
 

OK- here is my brain, ............- put the revamped 4 blade 16/15 no cup back on today. Still have a hum but now at 700 rpms only- gone at all other speeds. Its going to have to be tolerable now. Speed numbers-
3000 rpm's, 19.5/20knots 10.4 to 10.6 gph. [img]images/icons/smile.gif[/img]
3200 rpms, 21/22 knots 11 to 11.1 gph [img]images/icons/smile.gif[/img]

3500 rpms 24 knots 17 gph [img]images/icons/rolleyes.gif[/img]
3800-4000 rpms 24.1 knots 18.5 gph [img]images/icons/shocked.gif[/img]

All on a crossing over tide with only a slight breeze

whadda y'all think ?

Pretty happy except for that damn humm. Think I might have hit something on the way in.Everything seems to be alright. Was tog fishing yesterday in my friends old 23 formula and we hit a 2 x 4 on the way in. Lots of crap from Isabel still floating around.2 x 4's, 4 x 4's, piers, telephone poles, you name it.sux. 3000/3200 is my normal cruising rpms , glad to see the numbers look good, better than what I expected

Re: Fuel Numbers for my "Speed Demon" (not)
 

Miles,
I am surprised you didn't get any more at the top end (3800 - 4000). Assuming 10% prop slip your boat should hit 30 knots as set up [img]images/icons/confused.gif[/img] . I know a 4 blade loses some speed compared to a 3 blade but I didn't think it was this dramatic.

Re: Fuel Numbers for my "Speed Demon" (not)
 

Craig, as Mike noted, what happened to your top end? Seems like yout not turning up? Maybe I'll go 16x16 with a five degree cup [img]images/icons/confused.gif[/img]

Re: Fuel Numbers for my "Speed Demon" (not)
 

My top end numbers are probably not real accurate so take them with a grain of salt. I hesitate to leave it running wot for long period of time even for the gps to catch up. I also think that I am not getting /or am losing several knots because of the keel guard on my boat. There is not a smooth transition forward where it is bolted thru the boat and the whole thing doesnt really make aerodynamacilly (sp) smooth flow possible. I'm certain thats why everyones numbers are better than mine.Another thing I noticed yesterday is I have some play(wobble) in my rudder(oversized). Hopefully I can get rid of the wobble by repacking it?? If there is wobble Im thinking that is giving me even more resistance slowing me down even more?? I toyed with the idea of removing the keel guard this past spring but after some thought figured that it is a better idea to leave it on and protect the running gear and lose a few knots.

Jeff if you put cup in it arnt you defeating the purpose of taking the pitch out???

yall might have seen these before but this is what I mean-the first picture you can see the blunt edge that sticks down an inch or so that is definitly in need of some kind of fairing in. The very back part of the foot also has a lot of drag Im certain because it is not totally stationary.

http://images.snapfish.com/338%3A%3B...B56%3A65nu0mrj

http://images.snapfish.com/338%3A%3B...B56%3A64nu0mrj

heres one with the 4 blade on it right after hurricane isabel-notice where the tide level is
http://images.snapfish.com/338%3A%3B...B56%3A63nu0mrj

[ November 03, 2003, 07:51 PM: Message edited by: Miles Offshore ]