CPseudonym
Moderator Emeritus
Congratulations Ted, a resounding success ![Thumb :thumb: :thumb:](https://www.trawlerforum.com/forums/images/trawler/smilies/sk/thumb.gif)
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![Thumb :thumb: :thumb:](https://www.trawlerforum.com/forums/images/trawler/smilies/sk/thumb.gif)
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I know that has to be an awesome feeling to have it in the water after all this time!
Congratulations Ted, a resounding success![]()
Holy $#@&*%$! Looking great there, Ted! Must be a great feeling to have that much success on such a huge job. You found a great team member in Sean!
Welp...I don't know quite what to say except that if your goal was to splash this baby this year, you made it be the skin of your teeth. I'll bet you checked the bilges a few times before heading home! Can hardly wait to hear the feedback on the waterways south. Still in the mid 80's here.....come on down!
Great result. Congratulations!
Now don't ya just wish is was August? Then after she was splashed, Cocktail Time!
Great job you guys! I forgot Shawn dosent drink. Oh well, I'll have one for him.
Well done, must be a great feeling and a wonderful achievement....
No, that's bird poop. Thanks!Missed a spot,......... just kidding, awesome, congratulations!
The case for repowering:
To cruise the boat at 7 knots the engine runs at 1,200 rpm. 6 knots is 1,000 rpm. Less than 6 knots your taking in and out of gear. The engine doesn't run efficiently at 7 knots, less than 2 mpg. Spent a lot of time running HP requirements on software programs such as you find on boatdiesel.com. You can come up with all sorts of numbers depending on how you classify the hull shape etc. (garbage in, garbage out). The realistic range for HP needed for 7 knots is somewhere between 25 and 45 HP with 35 being a pretty realistic number. So, assuming 35 HP, the 450 HP Cummins is running at 8% of it's capacity and generating roughly 10 HP for every gallon it's burning. Simply, this engine is designed to run at 1,600+ rpm and generate hundreds of HP.
Need to find an engine around 100 HP with the same WOT rpm that I can bolt my ZF 280.1 transmission to. Then I only need to change to a flatter pitch prop. Logical choice was the John Deere 4045TFM75 M1. The engine is 107 HP at 2,400 rpm M1 rating (continuous duty). The Cummins is 450 HP at 2,500 rpm. My ZF 280.1 gear bolted right up, albeit substantial over kill.
So here are the numbers: Sold the Cummins sight unseen to a waterman of the marina for $15K before I brought the boat to Maryland. Bought the new engine for $17.8K. Add another +/- $4.2K in materials (custom stainless exhaust riser, lift muffler, exhaust pipe, engine mounts, transmission cooler, transmission service, and a bunch of misc. Add +/- $3K for Sean labor (and 100+ hours of my labor). That brings me to around $10K. Still need to buy a new prop, but will run the old one to generate some numbers to work from. Expect the boat to cruise at 1,600 to 1,800 rpm at 7 knots. Peak torque (full efficiency) is reached at 1,400 rpm. WOT (2,400 rpm) should be somewhere near 8.5 knots.
So you probably want to know what I think I will get for fuel consumption. The closest production boat with the same motor was the Kadey Krogen 39 (discontinued). The KK39 is a little shorter LWL (about 4'). The listed displacements and drafts are almost exactly the same. Hull shapes are different as the KK39 is full displacement. So it's roughly comparible. The question is, do you believe Kadey Krogen's advertised numbers?KK claims the 39 burns 1.3 GPH at 7 knots with the JD 4045T. That's a little over 5 MPG. I'm hoping to do at least 3 MPG which is 2.3 GPH. I will be ecstatic if I hit 4 MPG / 1.75 GPH.
Ted
That's economical then, and a pretty short snagging list for the amount of work you have done....
It'll never be finished though![]()
Congratulations Ted!! With all rewiring and refitting you and Sean have done, that is an incredibly short squawk list.
I know this has probably been said before, but it’s worth saying again, thank you for keeping us abreast on your progress and reasoning for the upgrades you did. For me, this thread was like a ‘how-to’ manual. In about three months, I will be doing a re-power, updating systems, installing a lot of stuff and trying to make sense of the plumbing and wiring currently down there. This thread, along with the ‘Show us your ER’ and ‘Old Fat Men and Engine Rooms’ have been a great inspiration for me to do the ER right.
Please keep updates coming. When this thread end, if it ever ends, I guess I will have to take up reading ‘War and Peace’ or ‘Moby Dick’.
Bob
Man I really like the profile of your boat. To coin another, she's real "shippy" looking. I showed a pic to my ocean alexander, and it shuddered. Dont think I wanna know why either.
Do you think the mpg's will drop a tad as the rpms go up with the new prop?
Ted
After I repowered my boat with more hp in otherwise similar engines, my rpm at 8 knots dropped slightly, from 2750 to 2500 or so. No change to the props. On urging by my Volvo Mechanic "your engines will run more efficiently and last a lot longer", I repropped by Adding 4" of pitch. This brought my cruising rpm down some more. I now cruise at around 2000 rpm and WOT only gets me a little more, maybe 2300. I have had these conditions now for about 12 years, with no ill effects. In fact, my fuel consumption dropped significantly, paying for the cost of the repower and repropping within the first 5 years. My Volvo TAMD41s would run at 3300 WOT if propped for it, but there is no need to get them that excited.
Just sayin, you don't need to rush those props in to change their pitch.
Ted, the HP18 looks good! How is it on glare? I will also be redoing the panel and installing a computer in a cradle much like you did.
Bob
Ted, it's not bad, but certainly not as crisp as your other displays. I sure could live with it.
Ill try and find the company in Ga. that can take a laptop and redo the display portion with 3M's transflexive layers and make it daylight bright. I've done it to 2 laptops running as depth finders and the results are remarkable.
Direct sunlight makes it brighter.