12 knots diff with same engine...

joakimhansson · 30 September 2007, 12:43

Fountain 35 and Baja 342

simular length, simular weight, both have the 420hp mercrusier x 2.

And the diff is 12 knots.

The fountain have a stepped hull with planing pad and the baja have a "standard" hull.

How much is the hull and the engine installations (look at pics). 2 First is Baja.

all pics is from the manufactures homepages.

John Kennett · 30 September 2007, 17:51

A quick look on Google tells me that the 496 Magnum HO gives 420 hp, but the 525 EFI gives 525 hp . . .

John

joakimhansson · 30 September 2007, 17:59

Quote:

Originally Posted by John Kennett

A quick look on Google tells me that the 496 Magnum HO gives 420 hp, but the 525 EFI gives 525 hp . . .

John

Yes, but the pics is from the manufactures homepages. Both boats have the 496 Magnum HO with 420hp. I don´t have pics on my friends engines and hulls....

The baja did 62-63knots with 2 x 420 and after installation of superchargers the hp was around 2 x 550hp and with long time testing with propellers it did 69-70knots.
The Fountain did 73-75knots with 2 x 420hp direct out of box (factory).

John Kennett · 30 September 2007, 18:36

Quote:

Originally Posted by joakimhansson

Yes, but the pics is from the manufactures homepages. Both boats have the 496 Magnum HO with 420hp. I don´t have pics on my friends engines and hulls....

Ah, OK. You said look at the pics, so I did!

You might get a more informed answer on www.boatmad.com where they know a bit more about fast boats.

John

Limey Linda · 30 September 2007, 18:46

One boat has staggered engines the other does not. Big difference in performance

joakimhansson · 30 September 2007, 21:19

Quote:

Originally Posted by John Kennett

Ah, OK. You said look at the pics, so I did!

You might get a more informed answer on www.boatmad.com where they know a bit more about fast boats.

John

Limey Linda find the word i couldnt find. The pic on boats was most for people to se what kind of boat it was, engine pic was because i couldnt find the word staggered engines.

I will try boatmad, just curious how much staggered engines do and how much the stepped hull does.

bogib · 30 September 2007, 21:39

More over the guys on www.screamandfly.com are far more capable of telling you all the difference you are after Joakim.

The guys on BM are more for phantom and ring thingies

Bogi

Nos4r2 · 30 September 2007, 21:47

I just love the look of all that stainless pipework

bogib · 30 September 2007, 21:55

Quote:

Originally Posted by Nos4r2

I just love the look of all that stainless pipework

Yanks love all the bling bling wherever on thingies that moves

Will look up boat rental in New Orleans and hope to find powerful bling boat to blast on

Also for my upcoming boat project I will need loads of bling bling from US

Bogi

Nos4r2 · 30 September 2007, 22:06

I think it comes from cutting bikes around. I hate chrome but give me polished ally or stainless and I'm dribbling

bogib · 30 September 2007, 22:10

Quote:

Originally Posted by Nos4r2

I think it comes from cutting bikes around. I hate chrome but give me polished ally or stainless and I'm dribbling

Hate chrome myself so it will polished ally and/or stainless

Bogi

Limey Linda · 30 September 2007, 22:13

Staggered engines put the two props closer to the centerline of the boat so that the hull is higher out of the water and thus less drag. If you like bling bling then go to offshoreonly.com and look at their classifieds.

Cookee · 01 October 2007, 13:15

Quote:

Originally Posted by Limey Linda

Staggered engines put the two props closer to the centerline of the boat so that the hull is higher out of the water and thus less drag. If you like bling bling then go to offshoreonly.com and look at their classifieds.

Sorry to disagree, but I don't understand how it would get the hull out of the water more by moving the props closer together?

My understanding of staggering engines is that it moves the lateral centre of gravity closer together and helps with stability, lowers the centre of gravity as the engines are lower in the hull, and if you have the props turning in rather than out will give more speed although it will be harder to drive. The fore and aft centre of gravity will be moved forwards as well, but with many boats of the size you are looking at this will be an advantage.

Hull design will have a big part to play, and higher speeds are most often associated with a "firmer" ride, stepped hulls add speed by reducing drag - with a twin stepped hull the boat is riding on the rear step and the transom in flat calm conditions - less drag more speed.

The reason why not every boat has steps is that handling on corners can be compromised, and depending on the design it can mean a firmer ride - of course less drag also means more fuel efficient!