99' 400 Sedan Bridge 300 hp Enough power???

[SR400DB]

I have posted this many times, I have an '03 with the Cummins 450's (6CTA 8.3) engines. Great engine package for this boat.

I just ran the boat from San Francisco to Seattle. We burned .8 gallons per mile total for the trip. We did run the generator the entire way (first time for me, usually. I just run the genny on as needed basis) . The genny running and some very big seas brought my mileage down from a typical 1 mile per gallon that I have seen in the past. The boat was also very heavy, three adults, and approximately 650 pounds of additional gear. The boat still cruised at 22 knots at 2100 rpm's. I have only docked this model with the 350 cats so I cant offer much there.


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[NaughtyDog]

I have posted this many times, I have an '03 with the Cummins 450's (6CTA 8.3) engines. Great engine package for this boat.

I just ran the boat from San Francisco to Seattle. We burned .8 gallons per mile total for the trip. We did run the generator the entire way (first time for me, usually. I just run the genny on as needed basis) . The genny running and some very big seas brought my mileage down from a typical 1 mile per gallon that I have seen in the past. The boat was also very heavy, three adults, and approximately 650 pounds of additional gear. The boat still cruised at 22 knots at 2100 rpm's. I have only docked this model with the 350 cats so I cant offer much there.


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Thank you for the response and comments SR400DB, I am new to the CSR and am still finding my way around the site so I apologize if this was a frequently asked question. I would agree that your Cummins 6CTA8.3 would definitely be the preferred power package but sadly there are no local ones available in my area

. Only 3116's and 3126's. Let me know if you come across one in your stay in Seatlle though! I am currently researching any and all information I can get on 2000-2003 400DBs.:smt024

 

[swordfisherman]

Unless your bottom is in really bad shape, you don't have the correct props on the boat. Fully loaded you should be able to achieve 2850 rpm. If fully loaded you only achieve 2300 rpm you need to reduce the propeller pitch until you can achieve 2850 rpm. I believe that you get about 200 rpm per inch of pitch change. If you don't fix this you will kill your engines. The worst thing you can do to a diesel is overprop it. Also, you have to be sure your bottom is super clean and freshly painted before you do anything.

Good Luck,

Pete

Peter,

I believe the reason why i could not reach the proper rpm when fully loaded is because I am just plowing the whole time. My stern could not get up on plane so i stay at 2,300 rpm at wot. I have already cleaned my bottom by diving under and scraping barnacles and other growth. It helped a lot with speed and getting on to plane. But when fully loaded with fuel and water and 5 people on board, i would not be able to plane till after i burn at least 1/4 of fuel and dump or consume 1/4 water.

Thus with his question re the 3116's, I think they are underpowered.

 

[swordfisherman]

I have posted this many times, I have an '03 with the Cummins 450's (6CTA 8.3) engines. Great engine package for this boat.

I just ran the boat from San Francisco to Seattle. We burned .8 gallons per mile total for the trip. We did run the generator the entire way (first time for me, usually. I just run the genny on as needed basis) . The genny running and some very big seas brought my mileage down from a typical 1 mile per gallon that I have seen in the past. The boat was also very heavy, three adults, and approximately 650 pounds of additional gear. The boat still cruised at 22 knots at 2100 rpm's. I have only docked this model with the 350 cats so I cant offer much there.

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Geof,

There is a 200 hp diff between our boats. I believe even if you have the bigger engines you still get better fuel economy because the engines do not struggle much. Didn't you repower? Thats why you sold me those impellers? Btw i still haven't got them yet.

 

[swordfisherman]

Thank you for the response and comments SR400DB, I am new to the CSR and am still finding my way around the site so I apologize if this was a frequently asked question. I would agree that your Cummins 6CTA8.3 would definitely be the preferred power package but sadly there are no local ones available in my area

. Only 3116's and 3126's. Let me know if you come across one in your stay in Seatlle though! I am currently researching any and all information I can get on 2000-2003 400DBs.:smt024

Didn't Sea Ray offer the 400 sedan bridge with cat 3126's with 420 hp?

 

[NaughtyDog]

Didn't Sea Ray offer the 400 sedan bridge with cat 3126's with 420 hp?

Swordfisherman,
According to this Sea Ray manufacturer's brochure off their website, your 2000 400DB model could come with a CAT3126TA with 407hp. http://www.searay.com/boat_graphics/electronic_brochure/company1729/1C1_27_74DERNX1H052.pdf

...but this Sea Ray brochure for the 2001 400DB shows that it could come with a CAT3126TA with either a 340hp or 407hp model.http://www.searay.com/boat_graphics/electronic_brochure/company1731/8479_f.pdf

I guess you tell the difference off the serial numbers or plates? I had heard that CAT had some serious issues when they tried to push more HP out of the same block so I am concerned about the 3126TAs with the 400+ HP. This is why I am roaming around this site trying to investigate my best options. that is concerning that you are still having trouble planning with a total of 700HP pushing your boat. Have you had a chance to check your prop pitch yet?

 

[NaughtyDog]

....and according to this brochure the 1999 400DB could come with either a CAT3116 with 292HP, or CAT3116 with 340HP, or a 3126TA with the 407HP, so now I'm a little more confused!:smt101http://www.searay.com/boat_graphics/electronic_brochure/company1729/1C1_27_74DERNWYG008.pdf

 

[swordfisherman]

Hahaha me too. The plate on my engines say 350hp. I am waiting for a quote from my local cat dealer for an engine swap upgrade to a C series. I haven't researched much about the reliability of the new engines yet.

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[ZZ13]

I know I am resurrecting an old thread, but I am going through the same decision process. I'll be doing a performance trial on a '99 400DB with the 300hp CATS in few weeks. I'll post back my impressions. I plan to do it with a sparkling clean hull, full gas tanks and probably not much in the water tank (since that's mostly how I'd run it to keep some weight off the stern).

I noticed the original poster ended up with the 7.4 mercs after all that (or so the profile says that).

I trialed the boat yesterday. Surveyors and owner/broker were amazed I paid to fill up the tanks from half full (I think they thought I was nuts). Bottom was cleaned the day before. 6 adults on board. After some Q&A I found out the previous owner exclusively uses the boat at hull speed of 10kts at 1500rpm for local cruises. He has never filled the tanks up before. Never taken it to WOT. Props were 22x24. We maxed out at 18kts at 2500rpm (2400rpm on the other engine). Engine surveyor says going to 22x23 props will get it closer to the 2800rpm desired WOT.

It seems like a great boat for the way the owner runs it. For me, plan is to use it for longer range cruisers (100-200 miles) to visit friends, so not the right package for that.

Hypothetical question. How much of an ordeal would it be to swap 3116 engines with 420HP 3126 engines?

 

[ZZ13]

I trialed a different boat today: 2001 400DB with 430HP Cummins. Much, much different than the 300hp CATS. It went 28.7 knots (33mph) at WOT of 2600rpms. It cruised at 23 knots (26.5mph) at 2100 rpm.

 

[swordfisherman]

Yup I wish I had cummins too. Some members here top 30plus with the cummins.


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[mjmason1]

I have the 1996 with 350 hp cat's. When I brought her home Monday, with full fuel and fresh water, we cruised t 20-21 kts at 2500rpm. When we pushed full throttle we were doing over 24 kts at 2800rpm. Obviously we would have had better fuel economy at 18-19 kts.