420 DA Thread

Hello 420 guys, here a little 360 guy :grin:

Here are the building photos from Robski !!!!

I think they are a very interesting input on this thread!!


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Rob, Those are some great pic's. Did you get the washer/dryer option? If so where did they put it? JC
 
Thanx for posting the pics.. I was having resize issues...

Gettign the pics sent to me during its creation ... really helped ....

Hope u guys enjoy em....

One thing that surprised me was the amount of plywood...

oh and the size of the speakers in the couch.....

KIDS LOVE THE STEREO... the entire doc gets to hear high school musical..


Rob
 
Wow those pictures are great!! Thanks for posting them. Robski97, Did you just ask them to send you pictures when they were putting it together?
 
I gave my 320 log (i think) to the family who bought the boat from us. With 350 MAG Horizons I cruised at 3800-4000 RPMs and got around .85 NMPG (going on memory here) and I think it was a fuel burn of 24-26 gph. The 450 Cummins in the 420 turn 2100 RPMs at cruise and burn ~24 GPH. So--fuel burn is pretty close, but the 420 is going 3 knots faster and the diesel fuel is about a dollar less per gallon than 93 octane where I typically fill up.
The other issue is load--we typically loaded the 320 up with full fuel, water, guests, gear, and those 350s were really, really working hard to stay on plane if we had a lot of wind and current working against us. I had 14 people on the 420 last summer with all their gear, full tanks, etc. and the cruise rpm, speed, and time to plane were just about indistinguishable from the regular load of 2 adults, two kids, and our gear.
According to my 420DA log: in 2006 we ran 147 hours, and burned 3020 gallons of diesel for an average of 20.5 GPH. I have no "no wake" zone to contend with at my Marina, so most of my run time is on plane at 2100 RPMs. I am pretty happy with the economy of the diesels given that I am pushing 45 LOA and 14-15 tons of boat on a 14' beam.

regards,
Skip
 
I know the feeling about the 350 mags. Whenever we go for a cruise full fuel, full water a few people and lots of gear aboard the boat just feels sluggish. We also have worse economy at .5-.6 mpg over this past season usually in the 3300-3800 rpm range. A good bit of time we ran in rough seas so I am taking that into account with my mpg calculations.

Now for another question, how is the ride compared to a 320.
 
Bridog,
I asked for the pics.... They were great about it ...

I love the boat... Great manners.... Been in some snot... 4- 6 close together... She was a champ....

Couldnt ask for a better ride.... or a better power plant...

Im sure skip can add alot more....


Rob
 
It is really hard to compare the boats. The 420 is much bigger (10' LOA) wider (2.5') and heavier (almost double the weight-7 tons vs just over 14 tons loaded). The combination of these three factors, plus the steady torque of the diesels, makes for a dramatically different experience aboard in a variety of conditions. On a 420DA, there is no real sensation of "coming on plane". You simply advance the throttles until you achieve desired cruise RPM. There is a pronounced acceleration kick at 1800 RPMs when the turbochargers wind up; but there is negligible bow rise. I never use my tabs, unless I need to trim port and starboard, or lower the bow in sloppy conditions. I've run the boat in 3-4' and not bothered to slow down below 22 knots. In May of last year we elected to head about 35 miles downriver and spend the weekend. As the tide was going out, the wind kicked up to 30 knots sustained out of the south..so wind was against tide, which made for a pretty sloppy sea on the bow and starboard quarter. Several boats, including 26' to 35' Sea Rays from ourlocal dealer's marina, turned back on the same because of the conditions. I trimmed the bow down a bit to break the slop and maintained 23 knots all the way. I had to turn the windshield wipers on occasionally due to wind blown spray. My family fell asleep in the cockpit. A great riding boat.
One issue I had with my 320 was bow rise coming on plane. I had to use the tabs, all the throttle I had, and stand up to maintain visibility forward. The 420DA requires none of that.
Again, the 320 is a great boat, and my family and I had a wonderful time with ours. We just had an opportunity to pick up the used 420DA with Cummins power and are really, really glad that we made the move.
regards
Skip
 
Frank, I did not. Hope you are well. I am cutting shrink wrap and re-commissioning 10 March, having Cummins out on the 14th to do the services that exceed my DIY comfort level, ( I plan to wax while the Cummins tech does his thing, weather permitting) and then I will be ready to light the fires and burn some diesel. I can't wait. It has been a long winter.
regards
Skip
 
Oh I'm in Trouble...

Hey guys, I've had my 320 for only 1 year and now I've been looking at 40 and 42 and even a 44, what the Hell am I doing? I know I'd like one of these babies, please tell me why it's so great having Deisels over Gas, I know the difference's in a truck, but tell me aboout the engines you all have in these Monsters of Fiberglass. I would really like a 40, not neccessarily New either, I'd romance a new used boat too. But I'd really like deisels in her for sure. Man they are very expensive though, but are they worth it.
 
Do you really expect a logical answer to mans unquenching desire for a bigger boat ? OK.. the answer is "BECAUSE"........ :smt043 , and diesels are better..........because....

Now I have really Pis**ed off the gas guys.. Oh well.
 
Yea Frank, us gas guys are watching you. :smt021 :smt043

Boltman repost your question as a single thread to start getting some answers there. :smt024 Thanks.
 
Biggers always BETTER.........

LEt skip take u for a bay test... ull never go back!!!!!!!!!!!!!!!1

Gas boaters ,.,,,, who needs em... lol... JOKING !!!!

Rob
 
Just a quick follow up to my recommissioning/spring preparation thread. I have now run all systems except for my fresh water system (below freezing tongiht) and I really think the winterization checklist I worked from was on the money (thanks jlevin). The Cummins came through the winter just fine, as did the Onan genny.
My windshield wiper arms were looking pretty gray and faded. They pop right off with the removal of the nut and lock washer; I laid them out on the dock and sprayed them with three coats of rustoleum gloss black. Cheaper than replacing them. I bit the bullet on the $79 holding tank filter, but Kenpcfl was kind enough to link me back to his thread that detailed recharging the filter for under 5 bucks worth of PVC parts and Aquarium charcoal..a good afternoon project.
I uploaded SR Navigator 3.5.1 but have yet to fiddle with the significant features of the upgrade.
I have now 1 hour on the mains for the 07 season--enroute to about 150-175, I hope.
regards
Skip
 
Skip,
What did the cummins guy do??

When did he recommend u take apart ur heat exchngers ?

DETAILS .......

My dang marina wont let cummins in .....

they got this whole payola for work thing and cummins wants no part of it . Cummins would have to give my marina a percentage of the bill.....


Everyones got there hands in the jar ...


Rob
 
Rob, my marina does the same thing except the guys doing the work just pass it through to me. I don't like that either but it is the only way to get the work done.

Skip, did you have to do anything to the bottom paint? I have a few thin spots and plan to rough the spot with 80 grit and brush on a couple of new coats. Do you think I can get by without doing the whole bottom until next season?

Great to hear you guys are out on the water already. It will be another month until we launch.
 
Rob,
The Cummins Tech did the complete 3 year service last year, including valve lash adjustment. I was only at 147 hours, but it is an 03 boat. This year we did T-stats in the port engine (was getting a temp spike when the turbos spooled up on our last run of the season..did stbd last year)
Checked the coolant chemistry and strength in mains and gen set; replaced the main impellers (new sherwood impeller design is really user friendly) tightened the oil feed line to the port turbo that was causing a light coating of oil on the fitting; replaced the starboard tachometer pickup (stbd tach was 600 rpms off synch) and did a general once over of the engines. belts, hoses, zincs, aftercoolers all good. As regards flushing the aftercoolers, Cummins pushes every 2 years/1,000 hours; my tech said a fresh water boat like mine will go several years without aftercooler flush. The tech said it was obvious that I baby my engines because there is only very minor darkening of the white paint on the forward edge of the aftercoolers. A sure sign of C series that get run at or near wot often are dark brown aftercoolers due to heat. I cruise at 2100 RPMs, or about 81% of WOT, which gets us a nice 24 knot cruise and 24 GPH burn rate. I'll wind her up to WOT once in a while for a couple minutes at a shot.
Tech also said his shop has seen little impact yet from ULSD fuels in over the road C-series; I am inclined to think there is not enough data yet on ULSD impacts on marine C series due to slower migration of ULSD fuels to the marine users.

All this Cummins tech does is work on diesel boats. He said he had run into a few 480DA owners who thought the Cummins 480CEs and QSCs (basically my motors with electronic controls) were not enough for a loaded 480 dancer and as such were unhappy with their boats. I have no 480 sundancer helm time to substantiate but I thought this was interesting. I think the C series are a perfect match for the 420/44DA, but we are a bit lighter than a 48..

regards
Skip
 
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