Learing inboards

Just find yourself an old air cooled petrol engine (maybe a Volkswagen?), hook up a Thai longtail rig to it, and you are away!

But would such a contraption be allowed in Australia?

 

Having owned 50 motorcycles over my life, I believe some of them would make a great power plant for your project. Requirements:
1. Shaft Drive Motorcycle Engine (as opposed to chain drive) which will fit driving a propeller with minimum modification.
2. Crankshaft Orientation Fore & Aft, this eliminates the right angle final drive gears, which would add some additional frictional losses.
3. Liquid Cooled engine, giving good cooling, and far less noise than an air (or air & oil cooled) cooled engine, appropriate for marine engines.
4. Big Power Available, although high performance motorcycles are virtually all using transverse engines with chain final drive, some shaft driven options are available with big horsepower numbers.

The most appropriate choice here is the Honda Gold Wing, or Valkarie power plant. Six cylinder horizontal opposed engine, 125 Horsepower in stock form, 1800cc. This type of engine configuration has very low vibration, and is capable of well over 250 horsepower when souped up. Reverse gear included. Honda reliability.

From a functional standpoint, you would need to at least add a circulating oil cooling system for the transmission oil, which need not be too complex, tied into the engine oil cooling system. Also a thrust bearing on the propeller shaft is needed as the Honda transmission is not designed for significant thrust. Also all the stuff needed to meet marine requirements, intake flame arrestor, etc.

Retaining the original transmission/gearbox minimizes complexity, and may well suit using some selected ratio. This also can be had with reverse gear.

There are a few other options here, but the Honda Engine is clearly the best choice. Intact motorcycle engines are fairly plentiful due to crashes.

 

If truly an inboard you need to usually cool not only the block but the exhaust as well. Usually oil for both the gear and the engine needs some cooling help as well. Then you have adaption to some form of suitable reversible gear for docking is nice. So you would be machining and welding a water jacket exhaust, designing a good mixer and wet elbow. Setting up a suitable raw water pump and heat exchangers for the main, and oil cooler circuit. Then you have the machining of a bell housing adapter and flywheel adapter to attach a reliable gear. Doesn't take very long to make other options look viable for both time and financial reasons.

The curmudgeon tone is a byproduct of being in the marine industry for more than a few days. Its filled with dreamers and lofty ideals, most and I do mean most are never completed and are usually cut up and scrapped by either the dreamers offspring or whoever buys the house they died in....

Over time patterns emerge, too many new variables usually is a solid indicator of future garage full of what will be landfill rubbish that was someone's "revolutionary idea ".

 

Could a fully closed system be used for the motorcycle and 13B engines?

marine engineering Gareth: COOLING http://garethdonaldrees.blogspot.com/2011/10/cooling.html

I am allowing around 200kg maxish for the total engine package

 

Closed circuit is maybe a poor choice of words. When I say raw water I'm referring to a system like you linked above vs a traditional closed cooling circuit like a keel cooler requiring no external circ pumps. Haven't seen a truly raw water engine since a poorly made big block jet boat from the 70s...

 

There are enough light weight powerfull modern engines on the market. It begins with jetski or snowmobile engine, right up to modern car engines.
What you choose depends on local support and your technical abilities. Choosing an engine that delivers peak power at 8000rpm will severely impact your transmission choice, so it comes down to your abilities (or finances) to find a solution.
It's not clear to me what kind of power you want, but for 200kg there are enough options. Car engines: Honda L15, Honda K20, Toyota 4AGE, Ford Duratec, etc. Check your local racing scene to see what is popular in your area. Snowmobile/marine: Rotax 850 E-Tec Turbo, 42kg, 164hp, Rotax 1630 ACE, 88kg, 300hp.

 

Outboard motors are the industry’s answer to light weight and high revving power.
On your own, without massive corporate financing to drive engineering and R&D, you’ll never come up with a better mousetrap.

 

Nope.
Just because you fail to appreciate and comprehend what DESIGN is, and the endless steps and compromises in order to DESIGN and make a DESIGN a success, does not make it so.

You consistently and constantly ignore advice and comments on design issues and then cry fowl because it doesn't fit into your narrative/mind set. Design is a technical discipline, and requires at the very least a nod to the science and engineering behind these steps one must take. Yet because you are lacking in this respect, you think anyone offering such advice in this technical realm is not worthy of your time or unable to be 'creative' to think in your world view etc...and as such, you dismiss it out of hand without even attempting to address your own failings.

It simply begs the question... why not then just go ask a road sweeper, or an accountant or a nurse or...well, anyone that is not marine related.
Since you ignore those that are attempting to inform you and/or assist you, based upon your question, so why bother asking the "collective" on the forum .... if you're unwilling to listen, why keep posting?

 

I've fairly deep ties to two rather productive yards. They are extremely selective in trying to weed out potential project failures, as well as actively work to recycle/destroy all half completed projects and builds. Still many get through. One has a section we jokingly call the boulevard of broken dreams. I'll start a picture log from my travels as well as the plethora of half completed "revolutionary ideas " that get unearthed in barns, garages, and tent like structures all over the west.

Not as a scare crow but a cautionary tale, to plan concisely and heed advice politely handed down.

Back to the engine conundrum.

Mini jets are a big thing up here. Most are built with adapted jetski engines. My friend and his brothers and dad have adapted some wild engines. His father had a career building engines and his brother has a $$$,$$$ CNC in the shop. Spinning up parts is little more than code and raw materials during open tool time.

We were out there for fathers day admiring a built vtec adapted to a custom made jet intake. His dad piped up, "wish mercury or Yamaha would just sell us complete units again". Turns out it's a royal pita to build even when you have acess to tools 95% of handyman cannot even dream of.

That's the reality of much of this, high revving solid power to weight motors cheapest in the form of an outboard motor. Even the jet boats are best built with factory parts, the economy of scale is ever with Yamaha...

 

Ad Hoc
You have gone far enough without knowing me as a person. You will be unable to quote some clear examples for the bits in bold. The only ones I am ignoring are the "too hard to do" brigade

I am reviewing every constructive input, reading up further and coming back with links and listings that come up. I am opening my mouth to question "why not" to single line dismissals

From the tone of your writings, the only thing that comes to mind is maybe you feel you have to compensate for small physical stature or something, but be assured that I do not have the need to deal with anyone who is unable to engage a mental gear and chooses to react with animal instinct

Please refrain from contaminating discussions with this brand of rubbish. I do not take any pleasure in writing this and wish I did not have to

 

The old adage of quit while you're behind comes to mind.

So..unable to find examples of you failing to grasp and understand..., hmmmm:

And still not wishing to listen...

It goes on and on....and yet, you blissfully state in riposte to such:

ad nauseum...

You're not a naval architect/designer... everyone understands that. Most on this forum are not. That is not the issue.

But if you constantly ignore what people are telling you, simply because you don't understand it nor wishing to listen.... then why not take the next 10years like most NAs have done in educating themselves on such matters. Then when asked such a "simple" question from others, you can condense your reply from the past 10 years of learning into a one liner... in order to save the poster 10 years to learn such matters. Or not... that is your prerogative.

 

Please do not read any combativeness in the tone of this message as none is present

I had a desire for a lefty jazz bass that would fit in a drivers seat of a camry (zero neck sticking out of window). I could have just rebuilt an electric guitar with 4 bass strings but there other factors like string scale to mass ratios. Fatest strings at maximum scale that can fit on those physical dimensional limitations was the aim to ge the desired tuning and led to a headless setup. Parts for lefty headless do not exist. I am having to hand cut and file them out of blocks of brass. It was no pain but absolute pleasure, taking a year to carve this out of a slab of spotted gum with a scalpel. You just cant beat the wow factor and satisfaction in leaning back on the taxi, bringing this to life on the rank

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7yrs ago I needed remote outboard controls in a remote part of Fiji. I made this with the most basic of tools. Got lucky finding a pair of pliers that had matching handle covers. Has a locking action that wond allow gear change without bringing throttle down. Cut entirely out of a mental plan too

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Sometimes the challenges make it even more rewarding exercise man. A jetski engine is one of the easier options that I can talk to my neighbour about all day, as he is a ski tour guide and does all the servicing and maintenance on their fleet. Outboards don't really suit unless there is a way of using its weight to tune the COG of the entire boat and get the prop a lot lower. Seem logical to investigate inboards

 

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Just about everything that you have quoted has a question mark which makes them questions. How are questions equivalent to ignoring? Not in any language classes that I have ever taken

I am stating again. Please refrain from personal criticism, it pollutes the discussions. If you do have to take exception with anything you find in my manner, please take it to a mod. I do not enjoy writing this and will ask the question in a new thread to attempt evading your attacks. Please try to leave the personal stuff out of it and may I request that you do not bring that down either

 

That's actually a case of "when given a one liner, I ask a question to elaborate". Try not to distort everything to fit whatever the hell is that you have taken an exception to and stop the harassment

 

Saqa, is one thing to bandy about novel ideas for a boat, but to then start talking about marinizing a specific engine, when the duty of this engine is a mystery, the boat still being unknown, has crossed over into a scatter-brained approach that lacks any coherence. Get back to the boat !