Engine placement at bow

[SailRedemption]

Originally Posted by Pelagic

WHAT ARE THE SPECIFIC BENEFIT OF THIS PROPOSAL, THAT JUSTIFIES REINVENTING THE WHEEL?

Well, imagine an older couple who coastal or ICW cruises, getting down into a engine space below the deck isn't viable. It was hard for my dad to get down the engine room on the CHB Senator trawler to work on the two Perkins. Room to work on the engine is a huge plus, most engines in floor cubbies are ridiculous to work on. The design could allow lots of tankage for fuel, water, and holding waste. Allows a more open and accessible main cabin. More efficient prop and shaft angle which aids in slow cruise speed efficiency. Could allow a nice aft cabin that isn't restrained by mid/aft engine placement.

It's not a design to fill the 99% it needs to fill 1. I didn't read the design notes but this boat may not be used by someone to travel across the oceans, but the great loop or something similar. In my opinion, it's not reinventing the wheel, just changing the lug pattern.

[Terra Nova]

The engine and all its associated heavy equipment act as ballast to stabilize a boat. In order to be effective, ballast is located close to below the center of gravity, low and near the center of the boat.

The engine would be easy to access and ventilate if it were on deck. Its control cables and dry stack exhaust could be very short. Fuel could be gravity fed, possibly eliminating the fuel pump, if the tanks were suspended over the deck-mounted engine. Forward, mid and aft cabins would be uninterrupted. But there are very valid reasons things are simply not done that way.

Same goes for bow-mounted engines.

[Pelagic]

If we are going to do a fair comparison, it needs to be apples to apples

So let's compare this 46ft single engine Diesel Duck, owned by friends of mine



With the sales pitch 46ft Bow Engine room trawler, also single engine.

The Ducks engine room is very functional, full height and easily accessed from a fire door in the galley hallway.
Directly above is a spacious Pilothouse with comfortable Sea Berth for rough weather and safe access from both stern and side watertight doors.


The engine room layout makes service of all equipment very easy, including generator, not even shown on bow engine room and i think fuel tankage is split into 5 different areas, giving them Oceanic range and variable trim options.

[Terra Nova]

Originally Posted by Pelagic

...With the sales pitch 46ft Bow Engine room trawler...

The photos and drawings show a MID, not bow engine room.

[Pelagic]

Originally Posted by Terra Nova

The photos and drawings show a MID, not bow engine room.

Tera Nova, take a look at Post #1
Attachment 174145

Above is the sales pitch bow engine room drawing I am comparing to the well proven Diesel Ducks I show.

Now, can anyone tell me WHY I would want to place an engine there?

[Terra Nova]

I'm still waiting to hear just 1 practical reason to locate the engine room in the bow.

[Wckoek]

Originally Posted by Pelagic

If we are going to do a fair comparison, it needs to be apples to apples

So let's compare this 46ft single engine Diesel Duck, owned by friends of mine

Attachment 174140

With the sales pitch 46ft Bow Engine room trawler, also single engine.

The Ducks engine room is very functional, full height and easily accessed from a fire door in the galley hallway.
Directly above is a spacious Pilothouse with comfortable Sea Berth for rough weather and safe access from both stern and side watertight doors.
Attachment 174141Attachment 174142Attachment 174143Attachment 174144

The engine room layout makes service of all equipment very easy, including generator, not even shown on bow engine room and i think fuel tankage is split into 5 different areas, giving them Oceanic range and variable trim options.

Hello, the same designer George Buehler also designed another boat with engine at the bow as mentioned earlier, so he wasn't opposing to the idea either.
Tasman Sea

[Pelagic]

Originally Posted by Wckoek

Hello, the same designer George Buehler also designed another boat with engine at the bow as mentioned earlier, so he wasn't opposing to the idea either.
Tasman Sea

Yes, I know.....

Many good designers will play with an owners idea as a conceptual treatment.

That is what they get paid for and he has put a lot more thought into it than post #1

But still, his notes suggests its a radical idea and admits a number of compromises and unknowns that need study

I just wonder how many of them have ever been built?

http://georgebuehler.com/Tasmansea49study.html

[jimbunyard]

Originally Posted by Pelagic

Tera Nova, take a look at Post #1
Attachment 174145

Above is the sales pitch bow engine room drawing I am comparing to the well proven Diesel Ducks I show.

Now, can anyone tell me WHY I would want to place an engine there?

Glad you ask...

Well, were it not for historical inertia, for a displacement hull and ultimate efficiency, it would be the most logical place for the prop to be. (Disregarding vulnerability of course) And then a lot of the arguments against the bow mounting would be somewhat reversed.

However, we can't reverse-engineer history, so we're stuck with the shortcomings designed in due to, among other things, the lack of technological ability and, perhaps, imagination.

That DD engine room sure looks enviable, and the midships placement looks ideal for a rear drive/rear rudder arrangement. Given there is a large amount of fixed, non-variable mass in an engine, from a stability standpoint that may be the best place for the engine, though of course that also depends on the distribution of other fixed masses in the design...

As long as we're in the hypothetical world, here's a 'more to the front than rear' scenario, using technology that might not exist, but likely would if not for the inertia demanded by economic and political necessity...

Take an engine reverse mounted in the forward third, driving an efficient water jet with the intake center-keel mounted in the forward 20% of the hull, with direction and volume controlled outlets on either side somewhere along the forward 25% of the hull, thereby providing the more-logical-from-a-physical-standpoint 'tractor' propulsion rather than a 'pusher', and steering via the aforementioned direction and volume outlets. A small rudder aft would provide even better maneuverability.

There are of course several parallels; cart before the horse, fish are (generally) propelled from the tail but steered from the front, my favorite; one of the first, if not the first, use of an actual propeller on a marine vessel (a submarine no less) was over 200 years ago when a propeller was placed at the front of the vessel "Turtle", which was used to attack a British ship in NY Harbor, rockets are 'steered' by computer-controlled directing of individual nozzles, etc.

Not to mention azipods or cycloidal propulsion or engine placement in respect to those or any other esoteric types of drives.

So, yeah, the extreme forward positioning of the engine in the boat in the OP's original post fairly smacks of gimmickry....but of course, if it works, and, as you say 'the owner is happy"...

[Terra Nova]

Originally Posted by Wckoek

Hello, the same designer George Buehler also designed another boat with engine at the bow as mentioned earlier, so he wasn't opposing to the idea either.
Tasman Sea

In your link the only dubiously "positive" the author could think to mention was:
"...engine in the bow opens up the entire rest of the hull." The same exact thing could be said of a midship or aft engine location, that it "opens up the rest of the hull."

I'm certainly not impressed, in spite of the best efforts of those of you willing to try to make this sound like such a great idea.

[Wckoek]

There was a time saildrive was villified but over time it had proved its worth, as well as a lot of things.
Of course there are all the drawbacks as stated before, but it wasn't that those cannot be mitigated and a clear cut case that it wouldn't work, or not worthwhile while there are benefit in space gained, sound isolation and a lower total displacement/cost to the build.
I hope that one day ideas like this can be explored as well.

[Wckoek]

Originally Posted by Terra Nova

In your link the only dubiously "positive" the author could think to mention was:
"...engine in the bow opens up the entire rest of the hull." The same exact thing could be said of a midship or aft engine location, that it "opens up the rest of the hull."

I'm certainly not impressed, in spite of the best efforts of those of you willing to try to make this sound like such a great idea.

If placed midship there is a block blocking the way between the cabin and saloon/pilothouse etc. Instead of better flow of space.
Sorry, I am not selling anything, or pitching anything and don't even make it sounds like a good idea, I am asking why this hasn't been done in the first place.
Of course like boats and designs, opinions are always polarizing.

[ranger58sb]

Originally Posted by Wckoek

I wasn't too keen at the idea of having an engine under the v berth as well, but in reality we only use the v berth at anchor and couldn't imagine using it at sea, so it was a good use of space in this case.

Are you still talking about the installation pictured in your first post?

That doesn't look to me like the engine is UNDER a V-berth.

Looks to me more like the engine room takes up the whole of that forward space... from hull to main deck... and the comment about stand-up headroom would only be possible if there's no V-berth there...

??

Hence my earlier comment about space utilization...

-Chris

[Pelagic]

Originally Posted by Wckoek

Sorry, I am not selling anything, or pitching anything and don't even make it sounds like a good idea, I am asking why this hasn't been done in the first place.
Of course like boats and designs, opinions are always polarizing.

I understand and my negative reaction was to your first post drawing, which showed little thought.

Was that George Beuler also?

Beuler's Tasman Sea drawing shows a lot more thought but still a conceptual study and a work in progress.

As a marina liveaboard , with the occasional fair weather cruise, its layout might be attractive, if they were willing to risk being guinea pigs with a far more complicated and expensive shaft system.

Again, would be interested to know if it ever was built for that customer?

[Wckoek]

Originally Posted by ranger42c

Are you still talking about the installation pictured in your first post?

That doesn't look to me like the engine is UNDER a V-berth.

Looks to me more like the engine room takes up the whole of that forward space... from hull to main deck... and the comment about stand-up headroom would only be possible if there's no V-berth there...

??

Hence my earlier comment about space utilization...

-Chris

That was a reply to Logan 33 which a member mentioned, should have quoted the reply in that post.