Engine Sea Trial

BillD

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After a couple of sea trials I've narrowed down the DE hull to build.

The next step is choosing the engine. Most on this forum know my fondness of Cummins marine diesels.

"American iron" with reasonably priced replacement and maintenance parts with a vast dealer network and good availability.
Robust liter displacement, all the better for getting rid of heat when you are pushing 500 hp.

I've lined up a sea trial of the new Cummins QSB 6.7 marine diesel. The new QSB 6.7 sets the benchmark for this class of marine diesel.

There are not many marine QSB 6.7s in service yet. Production is ramping up as Cummins phases out the QSB 5.9 series.

The sea trial QSB 6.7 425 is being fitted in a new 32 SeaVee center console build. The owner is a charter captain based out of N. Miami FL. The boat is due to splash 1st week of January.

I plan on heading to FL early March for a 1/2 day ride to ....."see/hear/smell/inspect"....and feel the power of this new Cummins 6.7 power plant . This charter boat does 1,000 + hrs. per year of running and the 425 hp version is rated for "intermittent duty" 1500 hrs./annual usage.

The QSB 6.7 has an extremely flat torque curve and the 480 hp version (3300 rated) should move a lightly built 33 Flowers right along with a 2.5 gear swinging a 28X29ish prop.

I want to see 1st hand how this Cummins fits in a hull, service acess and look over the "packaging" of the whole engine with new after cooler and all the new features.

Hopefully I'll couple the QSB sea trial with the QSC 500 in Mike's 33 Flowers BEFORE it comes time to order an engine.

The Blackfin is on the market, when she sells (if she sells :confused:) I plan to have the major components and parts already chosen for the project !

FWIW

Bill D
 

captainlarry84

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Cummins is a winner. Their high RPM range which is not really high gives you a great power band to use. With a high RPM diesel you get a nice low idle speed, low smoke & great smoothness. Plus the benefit of using a 2.5 gear for a larger propeller with pitch to match.

Think about shaft speed which is always a key to longer running life on the shaft and bearings:

A 3300 RPM diesel with a 2.5 gear has a shaft speed of 1320
A 2800 RPM diesel with a 2:0 gear has a shaft speed of 1400.

That tells you a lot about the flexibility and technology of this new Cummins unit.
 

sevenjohn

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Bill,
Went to Flowers shop lst week. I was impressed with the 33. The workmanship ...truly impressive. fine looking boat. Hard to beat...great choice.
 

F/V Sophia Rose

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BillD you might want to consider listing your boat on NJ craigslist if you havent already. Lots of guys lost boats and looking to replace them. One guy told me there were 63 boats in his marina and 61 of them were lost! Thats a lot of buyers.
 

MouseTrap

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BillD you might want to consider listing your boat on NJ craigslist if you havent already. Lots of guys lost boats and looking to replace them. One guy told me there were 63 boats in his marina and 61 of them were lost! Thats a lot of buyers.

I was going to "like" this suggestion, but can't because of the destruction Sandy caused. But, it is a great suggestion either way.
 

Tuna Pursuit

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Cummins is a winner. Their high RPM range which is not really high gives you a great power band to use. With a high RPM diesel you get a nice low idle speed, low smoke & great smoothness. Plus the benefit of using a 2.5 gear for a larger propeller with pitch to match.

Think about shaft speed which is always a key to longer running life on the shaft and bearings:

A 3300 RPM diesel with a 2.5 gear has a shaft speed of 1320
A 2800 RPM diesel with a 2:0 gear has a shaft speed of 1400.

That tells you a lot about the flexibility and technology of this new Cummins unit.


Do you know if it is a wet sleeved block?
 

BillD

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25 Terry Jason with Cummins 370 power
BillD you might want to consider listing your boat on NJ craigslist if you havent already. Lots of guys lost boats and looking to replace them. One guy told me there were 63 boats in his marina and 61 of them were lost! Thats a lot of buyers.

Yes thanks, I did!

I gotta figure with ALL the damage to their homes, boats, the area and then waiting on insurance & it being winter and all,
nothing much will happen til March/April
 

F/V Sophia Rose

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I was going to "like" this suggestion, but can't because of the destruction Sandy caused. But, it is a great suggestion either way.

I agree but if there is a silver lining to any of this mess... the guys ive spoken to are excited to find new boats....
 

CEShawn

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I'm really curious as to what you expect to take away from the sea trial in a different, totally different hull... Not trying to be negative here but out for the common good.

Reason being is this. I repowered with a pair of 6LYA-STE Yanmars in 2000, I came to hate them. My friend repowered his Bertram 33 with them and he absolutely LOVED THEM. He didnt have the power issues I had, he didnt have the weird range of where the turbo kicked in, to get the hull over the hump that I had in our Luhrs 32. It was the way that the engine matched our hull.

Again not trying to take away from you as you are educating yourself but curious as to what is going to be gained. Besides a fun day on the water of course...
 

BillD

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25 Terry Jason with Cummins 370 power
I'm really curious as to what you expect to take away from the sea trial in a different, totally different hull... Not trying to be negative here but out for the common good.

Reason being is this. I repowered with a pair of 6LYA-STE Yanmars in 2000, I came to hate them. My friend repowered his Bertram 33 with them and he absolutely LOVED THEM. He didnt have the power issues I had, he didnt have the weird range of where the turbo kicked in, to get the hull over the hump that I had in our Luhrs 32. It was the way that the engine matched our hull.

Again not trying to take away from you as you are educating yourself but curious as to what is going to be gained. Besides a fun day on the water of course...

I am one lucky bastard! Wife and I have a Hollywood Beach condo, 25 mins north of this guy's boat.

She'll golf, I'll go for a "spin" in the boat.

Sea trial is just an "excuse" to get the "f" out of golfing !!!:D
 

CEShawn

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I spend quite a bit of time in Dania Beach taking classes for my engineering license... I can understand the golf comment... Stop by the Dusky factory for me, lol...love that place...
 
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