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

[roosevelt14]

Will I be happy with buying a 1999 400 Sedan Bridge with the 3116 Cats with 300 hp....or do I need more hp:huh:

Also what is the difference between the 3116 with 300 hp and the 3116 with 340 hp???? Thanks Todd!

 

[fwebster]

The differences in the 350 and 300 hp 3116's is in injector sizes and timing and in pump settings, other than that, they are the same engines.

The 400DB is a heavy boat so more power is going to be better, but this really isn't that much difference between the 300 and 350 hp Cats. There might be a more noticable difference in the 420 hp 3126 or the 480hp 6CTA Cummins.

 

[fc3]

There might be a more noticable difference in the 420 hp 3126 or the 480hp 6CTA Cummins.

Why is that? I thought that Caterpillar and Cummins used different rating methods so that the Cat numbers worked out to a smaller number for about the same power. Don't know if it's a difference of 60 hp or what. I just remember seeing that in print some years ago when Power Boat Reports compared a pair of Cats to a pair of Cummins in the same model boat.

Best regards,
Frank

 

[roosevelt14]

Thanks Frank for the info....
Is there any 400 sedan Sedan Bridge owners out there running the 300 HP set up???
if so what are you cruising at??? and what kind out top end are you getting???

 

[fwebster]

Frank,

The comparison I was trying to make was the larger hp engines vs the 300/350 hp Cats. In running the boats, you do feel the difference between the larger hp engines and the smaller ones.

As far as the 3126 and the 6CTA's I really can't tell a lot of difference between them except that the Caterpillars have more torque, so you feel more power in the lower rpm ranges. The 6CTA's may have more overall hp, but with less torque, you don't feel the 60 hp until you are very close to WOT.

 

[Matt]

Both the cat and Cummins engines work well in this boat. it is heavy but also has one damn good planing hull.
I have a 2001 with the Cummins 450 HP. with those my boat runs at 24 knots at 2200 rpm and at wot 29 to 30 knots. this is with full fuel and water and people on the boat.
I did test a similar boat 1996 with cats I don't remember the HP of the cats. it's cruse was around 22 knots and 25 Wot.

Matt

 

[osd9]

You'll generally see CATs spec'd with two HP ratings. The 292 is the 300 HP and the 340 is the 350HP.

 

[tobnpr]

I'd think that 300 hp engines in a 40' bridge boat would be a bit underpowered, esp. when loaded.
A 24 kt cruise with 450's seems to confirm that.

 

[fc3]

OK, this is what I was talking about. This is from the February 2003 issue of Powerboat Reports.

See page 4 under the heading Horsepower

Page 1
Page 2
Page 3
Page 4


Cat and Cummins did use a different rating system. But it's a difference of 20 HP @ a 450 rating. Not a big deal.

Best regards,
Frank

 

[osd9]

Ok....HP may not be HP but RPMs is RPMs....right??? Not if you look at the two speed charts in page 3. That doesn't make sense. If the motors are both paired to identical ratio V-drives and turning the same RPMs, you would think that they would make the same speed at the same RPMs...right???. To make it even more confusing, the Cummins motors are fitted with 24X28 props and the CAT motors have 24X27 Props....that would make me think that the boat with less pitch, turning the same RPMs should go slower.....BUT....it's going faster....I'm confused!!!!!

Would weight make that difference???

 

[Pseudomind]

Ok....HP may not be HP but RPMs is RPMs....right??? Not if you look at the two speed charts in page 3. That doesn't make sense. If the motors are both paired to identical ratio V-drives and turning the same RPMs, you would think that they would make the same speed at the same RPMs...right???. To make it even more confusing, the Cummins motors are fitted with 24X28 props and the CAT motors have 24X27 Props....that would make me think that the boat with less pitch, turning the same RPMs should go slower.....BUT....it's going faster....I'm confused!!!!!

Would weight make that difference???

But boy the Cummings once over 1500 RPM sure burns more fuel and going slower...Whatever the reason:huh:

 

[tobnpr]

Ok....HP may not be HP but RPMs is RPMs....right??? Not if you look at the two speed charts in page 3. That doesn't make sense. If the motors are both paired to identical ratio V-drives and turning the same RPMs, you would think that they would make the same speed at the same RPMs...right???. To make it even more confusing, the Cummins motors are fitted with 24X28 props and the CAT motors have 24X27 Props....that would make me think that the boat with less pitch, turning the same RPMs should go slower.....BUT....it's going faster....I'm confused!!!!!

Would weight make that difference???

Yup. Should be, all things being equal. Although they said there was no weight difference between the hulls (different model years), I suspect that was not the case.
The "listed" weight for a boat is just an estimate. I've read there can be significant differences in the same model off the same line.

Only other possibility I can come up with is the props themselves. Perhaps the CAT props were more heavily cupped...offsetting the pitch difference in the Cummins powered boat...maybe...

 

[Matt]

All I was saying is that considering that the 400 DB stock engines back in 96 when it was introduced were 7.4 Mercruser horizons which pushed it at 20 to 21 knots that having either Cat or Cummins engines would be an upgrade. the boat does have a great fast plaining hull. with the torque difference between gassers and diesels should make for a decent cruse speed even with 300 Hp motors.

 

[Trinity]

The simple answer is the 300 in my opinion is not quite enough but all in all it will plane and get you there

 

[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).

 

[swordfisherman]

Hi ZZ13, i got a 2000 sedan bridge 400 3 weeks ago. She has 350 hp 3126 cats with around 860 hours. With full tank fuel and full tank water i could not get her to plain. All i could run is 17-18 knots wot @2,300 rpm. When my fuel gauge drops between half and 3/4 and water half tank, i am able to go on plane and cruise at 20 knots at 2,600 rpms. Top speed at this load is only 23. I think the 350's lack the umphs.
420hp should be the way to go if you asked me.

 

[ZZ13]

Thanks Swordfisherman. Did you know all that before you bought it? Or did you sea trial it with a light load and then get surprised after purchase when you loaded it up?

 

[swordfisherman]

No i did not know that. This deal was a bit complicated. It was brokered by a friend of a friend. We were not able to do a real sea trial because at the time of purchased there was a typhoon in the area so the seas were rough. I was too excited and did not want to loose the boat to another interested party, so I jumped on it right away. Boats are hard to come by in the Philippines. But im still satisfied with her. I would just run at trawler speeds when shes full until i burn s little fuel. When im at a rush, ill dump the freshwater as long as theres availability at my next destination.

 

[peterkvs]

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

 

[NaughtyDog]

Hello ZZ13, please keep us posted as how the seatrial goes as I too am looking at a couple 400DBs with the 3116 & 3126 CATS and have been wondering if they will have enough HP with a full load. If any other current 400DB owners could chime in on what engine package they have and if they are satisfied with it, it would be greatly appreciated!