best trawler engine

[FlyWright]

It's too easy to think only in terms of one's own boat when, in reality, there are many other boat styles represented here in Trawler Forum. Maybe a small, FD hull only requires a little power and torque to operate at the speed of smell, but other boats here require real power to shine at their favored speed.

To each his own... That doesn't make one right and the other wrong, but generalizations typically fall short on the accuracy scale.

 

[Nomad Willy]

Al,
Just because I own a "small FD boat" " "operate at the speed of smell" .... "speed of smell" I love that Al.

I was not. I was talking about SD trawlers ... a typical SD trawler that has a hull that clearly is'nt a planing hull. Many boats that most think of as trawlers actually have a planing hull w a keel more significant than most planing hulls. Many of these trawlers that look like a trawler (like a Camano 31) but go 20 knots because they have a planing hull aren't true trawlers IMO but that's another debate. Sure ... Planing hulls masquerading as trawlers may need hump power or extra power to drag their huge transoms along but true trawlers w true SD hulls will not.

But re the "what is a trawler" debate there will never be a universally accepted black and white line between trawlers and non trawlers because in fact trawlerness (new word) exists in degrees. I can say this boat is more of a trawler than that boat and basically w all boats .... except those that are too close to call. And there are many many boats that are indeed too close to call.
So the answer to the question is not whether or not a boat is a trawler or not but how much of a trawler is it?

But no I was not thinking of my own boat. I have been guilty of that in the past though. But perhaps my boat is'nt as much of a trawler as many SD trawlers. After all the average trawler is clearly a SD boat .. not a FD boat like my Willard.

 

[FlyWright]

I give that definition wide berth. It's more fun to be inclusive...as long as we're not talking about including sailboats. That's where I'd have to draw the line.

 

[FF]

"multi speed transmissions would work on boats."

They do for special purposes ZF makes them.

These work better than CPP to match the boats propulsion load to the engine BMEP peak.

 

[Ski in NC]

ZF makes two speed trannies for fast planing boats, sole purpose is to get boat over the "hump". How is that better than CPP? CPP is the "cat's meow" as far as controlling engine loading.

 

[FF]

The ZF can just as easily be installed to allow a displacement boat to speed up the shaft , raising the engine load while doing the trawler crawl .

Same concept as a cruising prop to get into the BMEP sweet spot , with less chance of a dummy overloading the engine.

The CCP can bot change blade area only pitch , which helps a bit , but not as much as spinning the shaft 25% or 30% faster .

Crank in too much pitch and the prop just cavitates

Both would be great , but a really expensive way to save fuel.

An interesting concept is the far east drives where the prop is held underwater to accelerate the boat , and only half is under at speed.

This is low cost and efficient , but hardly OK for a mom & pop retirement boat.