RICHARD CUNY

Hi guys i bought a 24 monza from a international truck company back in late 80s they had a problem with the extra weight of the engine and could not be competive in the B class back then.
Rich

HabanaJoe

Richard,

Did the boat come from Giant Int. NJ, red, white deck "All Gere'd Up" on the side?

If so, my old boat, should be the only one of it's kind!

mthill

Absolutely, and I think this is one factor that people are considering when looking at diesels. You can back a diesel off 10-15% and be in a range where the mfg calls it "cruise" and run all day. I dare say doing that with a blown big block is asking for trouble.

This is only true if you don't gear appropriately for the diesel. Of course you can turn a bigger wheel, if you turn it slower. If that gets you the performance you're looking for, then it will work fine. This will cost you top speed, and could may make low speed maneuvering more difficult (idle speed isn't lower than gas, so the taller pitch will increase your minimum speed).

mthill

Your posts were a big reason I finally crossed over from lurker to poster. We share many opinions, yours formed through years of experience and mine through an unusual amount of time thinking about how best to bring a high performance common rail diesel to market. There a lot more to know than fuel systems. Some of it I have a good understanding of, some not. If you want to be blown away by complexity, study up on diesel engine control strategy and algorithms.

I believe a public discourse between groups with different experiences will ultimately lead to a better understanding of the strengths of diesel powerboats. It's clear to me that it is not as intuitive as many think. If diesel engines are going to be successful in this market, there needs to be a lot of relearning of things taken for granted. Most of the diesel knowledge floating around is from YEARS of experience with mechanical engines. Fully electronic common rail engines are a new frontier and we've only begun to understand what this technology is capable of (emissions, power, efficiency, durability, etc).

I have an rather lengthy essay I've written and been meaning to post summarizing what I see as the state-of-the-art in diesel powerboat integration. I'll post it this week. Habana Joe, I hope to see you comments, in particular.

HabanaJoe

mthill - I would love to read it!

In regards to fuel systems, they have always been the limiting factor with mechanical engines. Electronics have given diesels variable injection timing, multi pulse firing, etc, etc. Our old P series pumps, well you would re-grind the helix to try and change timing but again all of it static never dynamic.

When I read what you guys write about the fuel systems is just, well, the potential is unlimited in my mind what can be attained today!

Even after all that I think the biggest problem and I'm glad to see you agree with me is - people don't realize that a propeller doesn't have a brain. It only knows speed at which it turns to become efficent, not what drives it.

I read through some of the posts and people here with their cats are running 1:1.24 gear ratios. Well, not to be scarcastic but look at your prop speed and then they think somehow because you have a diesel the boat should go just as fast with 50% less prop speed????

The single limited factor to diesels in small fast boats is the lack of boost at slow speed. I wrote about our twin turbo set-up how one runs and not the other, I still think that system addresses the problem with the least amount of complications.

I'm ranting but thank you and firefox for your comments, they're a pleasure to read!

Joe Gere

RICHARD CUNY

Hi Joe
Yes thats the one that boat ended up in Canada by the way were is Marc now havent spoke to him in years have you. Joe what was the problem with that boat and the power.
Rich

HabanaJoe

Richard,

Mark fishes with me in NC, he works up in N NJ and designs fiberglass vessels for the chemical industry. He was working for me on the race boats as well, he was guy in Buzzi's shop when the boats were in Italy.

Problems with the Monza?

First a very good strong capable boat, in the rough for a little boat it rode very good. The problem was it was such a narrow boat 7' at best and a pure deep vee. The extra weight of the diesel just killed the speed. With 325 hp continious (365 peak) it would run only 65 mph and you needed a little chop. We ran about 3,600 rpm through a 1:1 gear.

That was 1985 and our first attempt at a diesel speedboat. We took a lot of people's advice and tried reduction gears and bigger props etc. Look at any of the older diesel boats, 50-55 mph was the wall they hit and couldn't really go much faster. With 1:1 we got into the sixities.

In 1988 when we comissioned the Maelstrom to be built, it was 23'6" with 8'6" beam, a pad bottom and notched transom. Same engine, same 1:1 gear and in a light chop the Maelstrom cat would pace us at 76 mph!!!!

We ran against Gene Whip's "Team Gulfwind" (APBA "A" kilo record holder 81 or 83 mph?) Velocity out in Sarasota Bay one day for fun with a good 15-20 breeze and just smoked him like nothing!!!!

So, the Monza was a good boat, just the diesel was wrong for that boat at that time. If you were to put in a Cummins "B" and a surface drive I think it could fly???

Quick note, we put a full 400 hp "B" in the Maelstrom for testing, again 1:1 gear. No matter what prop it wouldn't go any faster. We put such a large cleaver on one time that we jumped a wave caught a little air and when we landed it torqued the boat over onto the gunnel whipped around and snapped the outdrive off!!!!

Little props high speed is how to run diesels!!!!

The first pic is a 300hp naturally aspirated 6.9L that's why there are dual exhausts.

29Firefox

Joe! was wondering where you were hiding! Wanted to run an idea by you. Instead of a multi speed gear box. Use an MGX series Twin Disc gear with a smart shifter. Gear and prop for top end speed. Or use a regular Twin Disc and add a trolling valve. When doing low speed maneuvering just slip the clutches.

HabanaJoe

Firefox, check my old posts, we used to use a manual trolling type valve back in the day.

Twin Disc makes a good portion of the hydraulic cluthes that are used in cranes. That is how they can adjust line speed so easy without changing engine rpm or affecting pulling power. They slip the cluthes!!! Of course bigger clutch packs, cooler etc, etc.

With the 506 gear we did the same thing with their blessing and it does work. You need to know what your doing and you need to lock that up fast or else it burns quickly.

The name escapes me all the time but, a Don Shead boat came to the US for the Worlds and ran UIM 2 (red & yellow boat) and they had Sabre diesels (not the junk from Fl, these are UK) and they had the slipping trans in front of #3 drives. Kurts Marine here in NJ did some work for them while they were here. That boat opened my eyes to slipping clutches, but the trans were huge and massive coolers on them - alot of weight?

I still like the twin parallel (on demand) turbos better, as they agin in earlier rants follow the Fueling body of works which I believe Seatek subcribed to as well as I know you and mthill do - more flow/less pressure.

I relate to trying to make these race engines not all around pleasure engines - and when it got rough you could run on one turbo fine with a loss of power but in a Gulfstream crossing type race, you can't run wide open anyway most days so it's fine.

The default on the turbos was running on one so you could always get back on plane and finish. With both turbos open your dead in the water.

As my father says 6/one half dozen or the other!!

29Firefox

Joe,
I've messed with twin Turbos in parallel & in series. My personal favorite is the single variable geometry turbo. Holset provides Cummins a nice one. Gale Banks has good success. His Sidewinder QSB engine is everyday drivable and still good for over 200 mph on the salt flats.