Jack/Orca's Repower Thread

[Jackman]

Okay, so here are some real life figures. I don't have a floscan yet but I do know I did the same trip with the 454's and used close to 3x the fuel in gas.

800rpms (idle) 6kts
1500rpms on plane @ about 17kts
2000rpms 22kts
2200rpms 24.5 to 25kts
2400rpms 26.5kts
2800rpms (WOT) 32 to 33kts all by GPS

She ran flawless through 3-5's and 2-4's. I could not have had it work oput better. I do have a slight lean to port that I will check out but all in all a totally brand new boat. The 2.5hour ride from Leipsic, DE to my slip in Long Neck, DE was eventless, something I'm not used to for sure! The engines never bogged down from the current or wind. I went right through Indian River inlet against the wind and tide without any sign of the engines being week. I cruised most of the way down at 2200rpms but I almost think 2000rpms is acceptable for cruise as well. The engine temps never varied nor did the pressure until I pulled the throttles back to enter my marina.

It was kind of neat to pull in and have everyone who has been looking for me because I'm in the water late this year...give me a funny look when they didn't hear the big blocks they are used to hearing!

I think the first fishing trip will be next weekend depending on the weather.

I talked things over with the owner of Carey's Diesel and he suggested that we put lifting strakes on the boat because it does get squirrelly at speeds over 29kts because of the keel and the roundness of the hull. He said it would keep it from being so goofy at those speeds. This performance test was also done with a rougher bottom that has 20+ yrs of bottom paint on it. I will be stripping and barrier coating in the fall. I may see even better performance than I saw today. I think I may need different tabs as well but that will all be later...I need to recover from this repower and the shock of going so fast on my old Hat!

[sammidog]

Sweet Jackman! Those 370's would have been a complete waste of money. You would never have been able to use the extra power. Did you sell your 454's yet?

[UNIQUE_NAME]

please stop jackman, you're killin' me my 427's cost 28 gal/hr @13.5 knts.

[the kuz]

Jackman, if I remember the fuel flow charts right, you should be burning about 18 -20 GPH total at the RPMs you are cruising. You are about 2 to 2.5 knots faster than our series one 36C at the 2000 and up. We get about a knot more than you at the low end RPM. Please post actuals when you get your flowscans in. Check you throttle linkage - you should be able to idle at 600 RPM or a little under. Best of luck with your new boat! You have a right to be very proud of those results. Regards, Bob K

[Jackman]

I'll have to look at them myself. I have the exact same setup as Tony Athen's repower of Got Bait and that boat did 14gph total. I'm sure there will be some differences from that because no boat is the same.

No, did not sell them yet, the 454's, have not had time to push them but that is coming up with a bunch of other stuff left over from my repower. I think I'll put out one big list and work off that to sell everything.

I'll have to look up the specs for idle rpms but I thought it was about 800rpms. Too low and the engines and trannies might not interact well. We'll see. I think I'll let it the way it is until breakin and then talk to them about lowering it if possible. She does take off in gear!

[34Hatt]

So Jackman you were able to get 2800 rpm out of the 23" pitch???
Also what do you think of the loudness of them compared to your 454's??
Glad you had a good shake down and from those #s that puppy is flying..

Also I just don't understand about lifting strakes making it less squirrelly they will lift the boat out more which tends to make it unstable!

Enjoy your Summer I am on season too and every time I push those throttles and here the turbo whined up I get a rush.

[Jackman]

The guys at Carey's thought that since my boat has a keel and where the freeboard meets the underside of the hull is round my boat walks a little at speeds above 31kts. He thought that adding strakes (maybe I'm calling it something different) would make the hull less round in shape and cut back on the walking or bouncing left to right at higher speeds. They also thought I needed bigger tabs or at best a different style because they are not as responsive as they should be, even though they are fully functionable.

Yes, I did meet the 2800 rpm requirement by about 50rpms according to the tachs and digital tachs. I may make some changes to increase the rpms just a bit for those times when the boat has more weight on it, but we did the seatrial with a full tank and four guys on board with some extra stuff in the cabin so I think we'll be okay for now. I'm nothing but excited to be on the boat now. She certainly has more power than I need and I will probably keep her at 2200rpms or maybe even 2000 for most of my trips if not all of them.

They are quieter than my 454's but will be even quieter when I install the new sound proofing in the engine hatches. (We removed the old stuff because of being oily from the 454's before the rebuild job that was done on them....probably 25yrs of engine residue on them! They are quieter, smoother, more fuel efficient and push the boat faster. I'm actually on top of the wave when I cruise now.....before I was not even close!

What have you done to help make the paint last? I'm sure you know the paint on these engines isn't all that great as far as quality. Where do you see it start to deteriorate first so I know where to watch for it?

[34Hatt]

They are quieter than my 454's but will be even quieter when I install the new sound proofing in the engine hatches. (We removed the old stuff because of being oily from the 454's before the rebuild job that was done on them....probably 25yrs of engine residue on them! They are quieter, smoother, more fuel efficient and push the boat faster. I'm actually on top of the wave when I cruise now.....before I was not even close!

I had the same change totally different boat. And see you say quieter and smoother. That is what drives me crazy when people say diesels are to loud and shake the boat. Then the other comments about smell and smoke!!!
I also have my bow much higher then before and the boat is much drier. Doing a offshore trip next week can't wait!

Mine were used when I bought them and after reseaching boat diesel I decide to paint them with rustolieum and so far very happy with the results. Everyone does have that one complaint about the paint being not so good!!!