420da Sea Trial

[Rocket]

So we did the survey and sea trial today and documented the following numbers on an 04 420 with Cummins 6CTA-8.3

2200 RPM - 22 knots - Cruise

2760 RPM - 29.2 knots - WOT

Engine Survey was performed, all temps, pressure, boost was acceptable. Reading through some of the threads i see that this 04 420 should be at 24 knot, 2200 rpm with a WOT at 31 knots. They hauled the boat and the bottom was clean however i noticed that the props were differant sizes, which i caught by eye. We recorded the prop size and both showed 22 x 25 which my understanding is 22" diameter with a 25 degree pitch. So why would both props with the same stamp be physically a differant size? some crude measurements revealed the port wheel was about 22" and the starboard was 25". We pulled the maintenance records and the starboard side was replaced.

What is the correct prop for this boat? We tried to call searay but they are closed. You would think that the boat would not track straight. She ran straight. Also both engines recorded the same RPM with independent laser tach on the engine. What am i missing??????????

 

[Hampton]

http://www.searay.com/prop_charts.asp

It says you have to check with your dealer for larger boats.

 

[Steve36]

I have the 480CE engines on a 2005 420DA.
The prop size on my blades are 22x27 Light Cup Nibral.
They are manufactured by Hy Torq propellers out of Canada.
Hope that helps.

 

[Hampton]

I have the 480CE engines on a 2005 420DA.
The prop size on my blades are 22x27 Light Cup Nibral.
They are manufactured by Hy Torq propellers out of Canada.
Hope that helps.

What's your performance in those same ranges?

 

[Skip]

Mike,
On the same boat with the same engines I run 22 x 26 four blade nibral wheels. Assuming zero wind and zero current, full fuel, water, gear, and a couple adults aboard, 2200 RPM gets me in the 24.5 knot range.

Rated WOT on these motors is 2650 RPM, and that earns me right around 31.5 knots (and 44 GPH-ouch). I turn right at 2650 WOT. I think the boat you are considering is underpropped, or more precisely, underpitched.


regards
Skip

 

[mrsrobinson]

Our boat came with 4 bladed props, 3 bladed spare (originals) on the boat. We used her for almost 2 seasons and then had her pulled for bottom painting and prop tuning.

Prop shop called to tell me one prop was 1" larger than the other in diameter and one was from 1974 and one was from 1994, our boat is a 1995. My guess is the previous owner purchased them used (ebay maybe) and either did not know or did not care. We had the larger one cut down 1". The boat ran better, but honestly we never new it ran "bad" as it's how the boat was for us from day 1.

 

[Rocket]

My research is telling us that they are suppossed to be 22 x 25. I cant confrim with searay at this point because no one is around, including the dealer. It's amazing that they are differant sizes and you cant tell by running the boat.

Skip - Your numbers are more in line with the test numbers by Boattest. I am off by 2 knots all around.

The dealer agreed to pull both off, confirm with searay and reprop as per spec. Cummins is telling us that we need to re-survey the engines with the new props. They found it odd that both engines had identical readings with different size props. Any thoughts on this?

 

[Skip]

Mike,
I can't disagree with the selling dealer's proposed approach. Short hauling the boat, pulling the props, then re-propping with factory specification props makes sense. Then drop her back in and go for a boat ride. If the boat then turns WOT RPM on both engines and the speeds are close, I'd say you found the problem. I am not sure a second mechanical survey is called for from Cummins, but you may be able to negotiate with them on the labor rate for the second "survey" since most of the survey work on the mains is already done. For all practical purposes, you are really only looking for the Cummins Tech to go for a boat ride and verify WOT RPMs are to Spec.

As to consistency of RPM, tracking, and speed, I can only guess that perhaps the smaller diameter wheel on the starboard side has more pitch; other factors may include the Glendenning Synchronizer being engaged and keeping a steady RPM between engines and the AP keeping the boat on the selected course..but these are only guesses.

I commend you for your due diligence and refusal to hurry the process along. Getting this right before you take delivery is critical.

regards
Skip

 

[fwebster]

Proping a Sea Ray isn't a guessing game, unless there is something wrong somewhere. On popular boats like the 420DA, Sea Ray long ago dialed in what the correct prop should be.

The Sea Ray parts list for the '04 420 is confusing, but there were 2 Cummins engine packages offered in that year. The 6CTA, and its replacement, the CE engine. The electronic CE may have bigger props or more pitch since they produce slightly more power then the 6C's. The dealer/Sea Ray is the right place to look for answers.

One other point worth noting, on some boats, the transmissions have a slightly different ratio from port to stbd. You may see a very small difference in the props from port to stbd to account for the ratio difference, but it is something like 1/2" of pitch or diameter.

I agree with Skip on the need for an additional engine survey. As long as the engines produced rated WOT rpm's during the survey and everything checked out, nothing much will be gained by investing another few hundred $ in having a mechanic witness that again. If the engines didn't produce full power, then the mechanic surveyed them in an overloaded condition and the results may be skewed. I think a legitimate question for the Cummins service company is "What will I gain by having you recheck these engines and what will the cost be?"

 

[Rocket]

The original engine survey was not performed by cummins. The hull surveyor did the engine survey. I know this is not typical as you usually have the manufacturer do the engine survey however i found this guy was extremely thorough. Prior to hiring him he sent me a 50 point check list on his engine survey which was quite impressive as to what cummins churned out on the dealer's survey when they took the boat on a trade. Cummin's survey documented rpm's, knots and few temps. THis surveyor spent about 3 hours on each engine, performed a coolant test to see if any combustion product was present, listened to each injector at idle and under load, documented temps at idle, cruise RPM, and WOT. He also took oil samples which came back normal.

After calling my local searay dealer and speaking with cummins, they recommended the sea trial. I know it can be a sales pitch. I tend to agree with you on not spending the money. My only concern to have them survey is why am i not obtaining the published speeds.

They will have the boat ready for me on tuesday and i will speak to cummins today.

 

[fwebster]

I've gotten in on this discussion late, but I don't see where you told us your source for your "published" speeds.

If you are trying to achieve speeds Sea Ray published in sales or other marketing data, you probably aren't going to get there. The reason is that Sea Ray test runs their boats for performance with 2 average sized adults, 50 gal of fuel, no water, no waste, no gear, no food/supplies, etc. , only a CG kit containing number boards, a few life jackets and a small anchor and flare pack. Typically, a normal boat with fuel and water will run 2-4 kts slower that the speeds shown in the marketing info.

But the prop question and whether or not you can turn up rated WOT question do need answers.

 

[MrSeaRayMike]

Hello Rocket, you should have 22 X 25 4-bladed cupped props on your vessel. This is from an internal Sea Ray Manual...Regarding the "published" performance characteristics of your 2004 420 "Dancer" the tests were done in salt (not brackish) water...salt water being more bouyant. Also, your vessel was produced in Meritt Island Florida. They take every vessel out for a 1-4 hour run prior to being delivered to a dealership. They may or may not change props for your specific Sundancer. You can contact Sea Ray customer service 1-800-SR-BOATS and they can give you the specific props your vessel was delivered with...ask for Rusty, he knows how to sort through all the #@$%^&.. You know what I mean.

Good luck,

 

[Rocket]

Frank - I found the performance data on Boattest and Skip's numbers coincide with that data. I am about 2 knots behind on both.

After i sea trial with the new props, i will post the new numbers.

Mike

 

[Rocket]

Hello Rocket, you should have 22 X 25 4-bladed cupped props on your vessel. This is from an internal Sea Ray Manual...Regarding the "published" performance characteristics of your 2004 420 "Dancer" the tests were done in salt (not brackish) water...salt water being more bouyant. Also, your vessel was produced in Meritt Island Florida. They take every vessel out for a 1-4 hour run prior to being delivered to a dealership. They may or may not change props for your specific Sundancer. You can contact Sea Ray customer service 1-800-SR-BOATS and they can give you the specific props your vessel was delivered with...ask for Rusty, he knows how to sort through all the #@$%^&.. You know what I mean.

Good luck,

Thanks Mike - I will call them, I did find the same prop size in the parts manual - they read 22" x25" x 4.85" "Z" , not sure what the 4.85 and Z mean. I know 22" is diameter and 25" is pitch.

 

[Four Suns]

You can contact Sea Ray customer service 1-800-SR-BOATS and they can give you the specific props your vessel was delivered with...ask for Rusty, he knows how to sort through all the #@$%^&..

Rusty is back in customer service?

 

[tobnpr]

From one point of view, I could see how a port 22 x 25 could turn the same rpms if your stbd were something like 25 x 22. You can adjust max rpms by either pitch or diameter.
But I can't imagine the boat would feel "right". If I understood you correctly, one or both of the props is incorrectly stamped. While it's easy to approximate diameter, there's no way to measure pitch that I know of other than the prop shop. I'd have both props checked so I'd know what they really are.

I don't think the boat would "pull" unless the differences were severe. If I were to run my port engine at 2400 and my starboard at 2100 I'd sure know it from the out-of-sync vibrations, but I think the rudders would compensate enough to keep the boat tracking more or less straight. But I'm surprised that there wasn't an out-of-sync vibration to the boat at sea trial. I've got digital tachs, and I can "feel" if I'm more than 50 rpms off without even looking at the tachs.

Interesting- let us know how it ends up.

 

[fwebster]

Gary,

No....Rusty is still delivering boats. I saw him in Panama City last month. He was one of the guys Sea Ray sent over to tweak the new 43DA with Zues drives.

Also, the 1-800-SRBOATS number is now a marketing number to refer you to their website for info on most things Sea Ray, not customer service.

 

[Rocket]

So I have some answers. I emailed Searay and customer service sent me a spec sheet on this boat from the original sea trial at the merritt island plant. The correct props are the 22 x 25 4 blade nibral. As far as performance, they show a WOT at 2600 rpm with a speed of 27 - 30 knots, depending upon load and sea conditions. I was 29.5 knots so i am in range.

The prop scan revealed that both blades were indeed 22" Diameter with a 25" pitch. One blade design had more surface area with no cup which is equivalent to a smaller blade surface area with a cup. One blade was manufactured by Hy torq, and the other by B&H, i didnt take the entire name. Both blades were used by searay and are acceptable.

I feel like an idiot as when i took some crude measurements with a tape, i could have sworn that one blade was bigger in diameter :smt021. But when you look at them both side by side, the blade with more surface area looks considerably larger.

Kudos to Searay for the help and speedy customer service and thank you guys for the helpful input. We have some other small things to work out but it looks like i going to be upgrading. I will post some pics of the blades for you to see when i visit the boat this weekend.

 

[jrirvine1]

Hello Rocket, and welcome to the 420 club, you are getting a very fine boat.

For comparison, on our last long run in late October with full fuel, full water, 5 adults with gear for all, 1-2’ waves and mostly dirty bottom from a season in brackish water our numbers were consistently:

2200 rpm
22-23 knots
30 gallons / hr

You didn’t mention if your boat has the hard top. I have often wondered if this makes any difference in performance as compared to the canvas top.

 

[Rocket]

Hello Rocket, and welcome to the 420 club, you are getting a very fine boat.

For comparison, on our last long run in late October with full fuel, full water, 5 adults with gear for all, 1-2’ waves and mostly dirty bottom from a season in brackish water our numbers were consistently:

2200 rpm
22-23 knots
30 gallons / hr

You didn’t mention if your boat has the hard top. I have often wondered if this makes any difference in performance as compared to the canvas top.

It does have the hardtop, but with the 417 HP motors. Number look in line with yours. Thanks for the welcome, the family is excited!