Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   General Boating Discussion (https://www.offshoreonly.com/forums/general-boating-discussion-51/)
-   -   New Cummins/Mercruiser Project (https://www.offshoreonly.com/forums/general-boating-discussion/196140-new-cummins-mercruiser-project.html)

shueman 02-28-2009 02:36 PM

Cruises all day between 70-75, at 3500rpms....:cool:
Range is 450-500 miles...

Boat has just been offered up FOR SALE in the Classified...Bob's ready for a new project...:ernaehrung004:
CLICK HERE

Jassman 02-28-2009 02:54 PM


Originally Posted by vanthemanmorrison (Post 2794395)
so whats the top speed on her?


3500 rpms is top..so must mean 75mph..

Shueman..it might help with a price in the add. Good luck.

Swamplizard 05-28-2009 07:28 AM

sweet ride! We forget that diesels are made to run at 90% for long periods of time so this thing must be the ultimate cruiser....so nice!

Catmando 06-18-2010 12:34 AM


Originally Posted by 29Firefox (Post 2700863)
Who what where & when?:hitfan:

Banks first brought out a twin turbo 500hp Duramax. He has since modified it with a supercharger on top of the motor in conjunction with the twin turbos. This engine makes 800hp/900tq and is offered in a cruiser version with WOT@3800 and also in a performance version with WOT@5800.

Banks says the first two motors are the 5800s for a Customs boat. He didn't say what drives but SSM6s sound about right for this application, or maybe Arneson 7s or 8s.

Jeffboat 11-23-2010 07:43 AM


Originally Posted by shueman (Post 2810856)
Cruises all day between 70-75, at 3500rpms....:cool:
Range is 450-500 miles...

Boat has just been offered up FOR SALE in the Classified...Bob's ready for a new project...:ernaehrung004:
CLICK HERE

Does anybody know what happened to the boat. We are fitting a identical engine drive package into our 43 foot and would love to know how the boat finally was set up

hawaiianhopper 11-23-2010 10:00 AM

I think the motors and drives were pulled a long time ago. It has been going through the auction in SoCal for the past 4 months. I just looked and it isn't showing up, so maybe somebody scooped the hull up. If not, it will show up again in about a week. Last time I checked, you could get the whole boat minus drives and power for about $70K

HabanaJoe 11-23-2010 10:00 PM

If that is true it is a damm shame!

I've said it on here 50 times if not more, the problem is not the diesels it's the application, nobody listens to their own experiences going fast with gas power and just translates what they did to go fast into the diesels.

Well, maybe my luck will change soon, we'll make some money again and I mean no disrespect to anyone but I'll show you all how it's done!

Jeffboat 11-24-2010 04:48 AM

It is a shame, still, we are going ahead here in the UK with two boats in build using Cummins 480 NXT. Previously we have fitted Yanmar ASD8s. We have had initial problems with the NXT 1.35 ratio supplied with massive slip. The NXT only takes an 18" diameter prop and the torque is too much.
We are awaiting 1.15 ratio drives and then we will sea trial again. Will post speeds etc after that happens.

HabanaJoe 11-24-2010 06:08 AM

Jeffboat,

Can you post pics here, I never renewed my subscription?

If not can someone that can send me there email, I'm looking for some old pics to post and prove a point with?

Jeffboat, next, the boats your building will never be fast, no insults intended.

Answer me a question - if you were building the same boats but with 480hp gas engines what dia propellers would you be using?

The torque is not your problem nor is slip. You can only have excessive slip if the propeller is first turning at the speed it is designed to turn at. I would bet money (that I don't have- LOL) that your propeller first of all just is not even close to spinning the RPM it needs to spin to be effecient. I think too many people just assume that a propeller is designed to work at a wider range of speeds than it really is and therefore has too much slip.

Look at it this way, if I have a 1,000 hp engine at 7,000 rpms and I hold it back so it only can turn 4,000 rpms and now only makes 500 hp - do I still have a 1,000 engine? Some people would say "my engine is only making 500 hp, so something is wrong with the engine let me start checking the carbs or timing, etc, etc"

Jeffboat 11-24-2010 06:56 AM


Originally Posted by HabanaJoe (Post 3260107)
Jeffboat,

Can you post pics here, I never renewed my subscription?

If not can someone that can send me there email, I'm looking for some old pics to post and prove a point with?

Jeffboat, next, the boats your building will never be fast, no insults intended.

Answer me a question - if you were building the same boats but with 480hp gas engines what dia propellers would you be using?

The torque is not your problem nor is slip. You can only have excessive slip if the propeller is first turning at the speed it is designed to turn at. I would bet money (that I don't have- LOL) that your propeller first of all just is not even close to spinning the RPM it needs to spin to be effecient. I think too many people just assume that a propeller is designed to work at a wider range of speeds than it really is and therefore has too much slip.

Look at it this way, if I have a 1,000 hp engine at 7,000 rpms and I hold it back so it only can turn 4,000 rpms and now only makes 500 hp - do I still have a 1,000 engine? Some people would say "my engine is only making 500 hp, so something is wrong with the engine let me start checking the carbs or timing, etc, etc"

The props we used for our first trial were Merc 18" x 32" pitch 5 blade. They pulled 3450 rpm and the boat did 11 knots! We fitted 2" spacers and got the same results.
This was all done with CMD aboard.
This is a boat we have previously supplied with Yanmar/ASDi8, 1.28:1 and acheived 57 knots.The props for the Arneson were supplied by Rolla, 20" diameter x 27" pitch 5 blade. Rolla say we need 22" diameter to make 1.35 to work! They recomend an 18" for the 1.15:1. We have a pair of 6 blade 18" x 30" coming to try with the new drives.
Video of the arneson boat here; http://www.youtube.com/user/HuntonGe.../0/iOOOMj-pK5w.


All times are GMT -5. The time now is 06:01 PM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.