Coast Guard Trivia

[Drowned Rat]

Who can answer this interesting fact about the Coast Guard's Motor Lifeboats??

When the Coast Guard built their first Motor Lifeboat (MLB)... For those who don't know what a MLB is, it's a motorized boat that can maintiain it's watertight integrity even when flipped upside down. It also carries enough lead ballast in the bilge so as to "right" the boat automatically should it capsize. Anyway, the first boat was the infamous 44 footer and twin Cummins VT-903 engines were installed as the powerplant. After completing a few sea trials, the Cummins engines were replaced with Detroit Diesel 6V-53s. Every subsequent model of MLB, (30', 52' and the new 47') uses Detroit Diesel engines while the majority of the rest of it's small boat fleet, that use inboards, use the Cummins. The Coast Guard has had an exclusive use agreement with Cummins for years for applications where Cummins makes an appropriate engine.

Why did they change to Detroit Diesels for this application?d

 

[QC]

Re: Coast Guard Trivia

Because they'll run upside down?

Also, wasn't there a Willard 32' with a Cat 3208NA?

 

[Drowned Rat]

Re: Coast Guard Trivia

QC, you're no fun man. I thought I had a good one. Okay WHY won't Cummins engines run upside down.

 

[QC]

Re: Coast Guard Trivia

I wasn't really sure, but I know that 2 cycles are easier to turn on their sides for bus applications. I assume it is the way they are oiled, but I thought they still had a wet sump, so I am not sure what the deal is actually. Dry sump option?

Did you see my Willard question?

 

[Drowned Rat]

Re: Coast Guard Trivia

That's it pretty much. The Detroits have no intake valves, they utilize ports. The arosolized fuel in the Cummins' intake valves get blocked by the oil pouring into the cylinders when you invert the engine. Since the Detroit has intake ports that surround the cylinder, enough of them remain open on enough of the 6 cylinders to keep the engine running. It doen't like it, but it works. Once the boat rights, you just top off the oil that was lost and keep on motoring. Hopefully out of the surf8).

The USCG may have used Willards but I'm not that familiar with them. As far as I know they are not a true motor lifeboat. The Navy used/uses these boats more extensively I believe.

 

[QC]

Re: Coast Guard Trivia

No I don't thnk they are a MLB as you called them, just that they used Cats. Thought they were CG, now you got me curious again.

I almost didn't answer the trivia, sorry . . . I was thinking it wasn't fair, but there are some truckers here that will know about the sidemounted (pancake) Detroits in busses.

 

[Kevin70]

Re: Coast Guard Trivia

It would be nice if all marine engines were built like that.

 

[eeboater]

Re: Coast Guard Trivia

It would be nice if all marine engines were built like that.

Kevin,

How often do you drive your boat upside down?! dd

Just kidding..
Sean

 

[HAWKT19]

Re: Coast Guard Trivia

Thanks for info I'll pass it to the MK's here at the station. I'm still running the VT-903 MD on the 41's

 

[Drowned Rat]

Re: Coast Guard Trivia

I don't think you want to flip that 41 footer.d What station are you at if you don't mind telling.