Birthday boat

[Andy CParticipant @andyc56856]

Hi Amy

Bonkers, maybe, eccentric, a little, but boy it will be one fine boat (ship, due to size) who knows. I am sure the fine stern will perfectly match the fine bow, although comparison is out of the question as we have not seen your fine stern as yet. Pictures give a good hint of shapeliness though. But if this is in anyway in comparison to your earlier builds, we can expect great things.

Andy

[ashley needhamParticipant @ashleyneedham69188]

Amy. You are using the stuff wot you have to hand and that is to be commended., very green and so on despite having a ten garages worth of cars.

Are you contemplating having fairly solid sides as well?

I shall be very interested to see how you are going to carve the large prop from solid brass, or are you going to cast one? weld one up?

Ashley

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Thank you all for the support, crisis of confidence averted! This model will get built.

Ashley. The sides and bottom will be 1/8" ply. The vast bulk of the 8×2 will get carved away, as the build progresses. Untill then it will serve as a building jig.

The prop will be fabricated from s/s sheet.

Any advice on size and pitch would be greatly welcomed, as we are shooting in the dark a bit with this. My 2hp outboard has 7×3, but a 2:1 reduction. Our thinking at this stage is a 3 blade 3 1/2 " with as much pitch as we dare put on it. It will be direct drive.

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Hello again.

the head of a long bolt was cut off, and the bolt threaded into the end of the crankshaft.

A length of tube was slid up the prop tube, and the engine jockied around, and packed up, untill the bolt slid smoothly down the shaft.

The positions of the frames marked, fore and abaft the engine. (These will become the mounting points) and the measurements emailed through

I cut the halfmodel at the apropriate locations, traced and diamensioned the stations, and emailed the drawings back

(the middle section will be the engine location)

[Bob Abell 2Participant @bobabell2]

Happy New Year….Amy Jane and Lynn

I really do admire your engineering ability!……Well done, Ladies

The mounting of the shaft and alignment is to be applauded!

Can you show a photo of the engine with a ruler alongside, so we can get an idea of scale, as it is, the engine looks enormous!

I am highly amused, the manner in which you are scaling of the cross sections!

The build reminds me of a departed well loved folk hero of ours………Fred Dibnah!

Keep up the good work, girls!

Bob…….Dead cod fish look, slowly morphing into a Cheshire Cat!

[ashley needhamParticipant @ashleyneedham69188]

Amy. Just a few thoughts and in no way criticism, just a few observations and questions.

Although the bell housing of the V8 has very handy tapped bolt holes for mounting purposes I would seriously consider getting the angle grinder out and cutting most of it away for weight purposes. Perhaps not even weight per se but lowering the c of g.

I would make a mild steel prop first that can be easily cut down and bent, and then make a s/s one when the correct performance has been arrived at. There is no way of getting the prop right first time and a prop made of soft stuff will be easier to mod.

Does the V8 have an integral fuel tank or will you have to fit that somewhere separately?

Are you using a prop tube or is the shaft running in the exotic antipodean wood directly?

You are not having a flexible coupling by the looks of things? One can only hope the engine is very well balanced or the boat will shake itself to bits post haste. A flexible coupling of the disc type would be very easy to make, and then the engine could be rubber mounted.

Great project so far.

Ashley

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Happy new year all!

Thanks for your comments Bob,you are a gentleman, for sure!

As requested.

Engine is aprox. 13" wide x 10" long x 8" high, weight 10 lb.

Ashley

A mild steel prop makes good sense to me, cut and twist until about right, then replicate.

The engine is mounted as low as we can get it, given shaft angle, exhaust and carburettor position.

Some explanation regarding coupling;

We are planning on using an old fashioned cone clutch, as both clutch and coupling, which will be engaged by sliding the entire prop shaft fore and aft. Of course the amount of actual travel will be small, Lynn thinks perhaps 1/8" will do. A simple lever engageing a collet on the prop shaft and actuated by a servo, should work. With the motor idling at about 1200 or a little more, boat speed will still be considerable. Clutch parts will be turned from a softish plastic, (my old skate board wheels perhaps?) prop thrust will keep the clutch engaged. There is a prop tube, but the shaft will be running in the wooden bearings, the lower water lubricated, the upper will have a oil cup. I think the engine will need to be fairly firmly mounted.

Thoughts anyone?

The tank will be separate, gravity feed, (The carb is mounted low)

more photos of progress thus far.

engine mounting frames cut from 1/2" 5 ply. Slotting into the base makes for strong, accurate construction.

engine in position, (though not installed) The frames are the full width of the boat, 18" beam.

Thanks again

Aj & L

[Bob Abell 2Participant @bobabell2]

Thank you, Amy and Lynn

The utter squalor you are building your ship in, is very disconcerting and unbecoming of an engineering ladies team!

The sight is creating a bad impression and you may not make next years honours list!

Get it off the dirty floor and onto a clean bench, please

I notice the engine former slots into the scaffolding plank……..Where is the 1/8" plywood you mentioned?

No doubt all will be clear shortly?

Bob with eyes glazing over

[LARRY WHETTONParticipant @larrywhetton68737]

Hello Amy,.

first post to you this year, a great scrap yard challenge ,

nice motor you have there would drive a go cart ……. or a quater scale narrow boat….

now theres thought……..cheers Larry……..

[ashley needhamParticipant @ashleyneedham69188]

Ho Ho. Now we have a view of the width in relation to the engine I can see that earlier comments about weight reduction are indeed unfounded.

Can only agree with Bob regarding a bit of broom work. HOWEVER most of my work is on a workmate with a bit of kitchen top on it in the garden (when sunny of course). Amy you are brave giving a blow by blow account and visual representation (photos) of the inner workings of your fledging BEAST, and I for one have never been one for neatness on parts that do not get seen. Pictures to the editor of my builds are carefully edited before hand…project No5 is sitting on the dining room table looking at me now (it is quite small this one) and one would have to use a bit of imagination at this stage to envisage the finished article.

Not sure about clutch parts from plastic, plse explain!! An automatic (centrifugal) clutch would be easy to make? or not. Need to find an old petrol lawnmower and pinch the clutch off it, easy option.

Larry. Do not even THINK about putting a V8 in your canal boat! some people..

Ashley

[shipwrightParticipant @shipwright]

Hello Amy,

In model boat terms this is a large project by any measure. I know from what you have said in other threads on the MB website that you have designed and constructed full size boats. Approximately what angle do you usually set for propshaft inclination ? I was intrigued to learn that the propshaft rear bearing will be simply a hole through wood – won't the steel shaft wear the bore too much ? And what will you use to prevent rust (propshaft and propeller) ?

Don't want to dampen your spirits but how do you ensure that the engine cuts out if there is a problem with the radio link or a servo failure ? – if one of my model boats hits something then the effect is undesirable but unlikely to cause serious harm (to people or property) ….. but if your boat goes out of control it could cause significant damage or injury.

Ian

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Hello all.

Bob , sshh… Lynn might be listening! (I know, the garage is disgusting, but country bumpkin, red necked hill billies, What can you do? A couple of years ago, there would have been two horses in there as well!)

I never said any of that, Lynn.

I love watching builds unfold, and seeing how things that don't make sense now, fall into place later on. (or not!) Hang in there Bob, in nothing ealse, it's more interesting viewing than the tv!

We are still not sure about the clutch arangement, A centrifugal clutch would be simpler, but in my experince they don't really start working until a few thou rpm, where as the cone clutch will work down to idle speed. I'll post a drawing shortly.

Ian, thanks for your input. The shaft angle on this boat is 15 degrees, which is steeper than I would like, but due to the boat having no rocker is required, to prevent the engine being to far forward. The boat really couldn't be any shorter. The prop shaft will be stainless steel, and the wooden bearings were once used on small, fullsized boats in the distant past, with motors only a little larger than this one. There is no side loading on the bearings, so friction is minimal.

Whoops, Kids are up, got to go, will continue shortly….

Thanks

[ashley needhamParticipant @ashleyneedham69188]

All, didn't they used to use Lignum Vitae (is that the right spellin?) wood for bearings in the steam age? Tough stuff. There would not be an issue of the wood swelling up WOOD there??

Talking about tidy sheds/garages, I always have a tidy up before starting something, however it doesn't usually take too long before it gets really UNTIDY due to all the tools and wood bits I have been using being littered around. Already I have a small mountain of 4mm ply parts form the current No5 proj amassing..and I have been gaily cutting up bits I had earmarked for use elsewhere.

Oh for a workshop like DM`s..

Ashley

[Bob Abell 2Participant @bobabell2]

Amy and Lynn

Can we see a cross section drawing through the motor shaft, showing the prop shaft and clutch arrangement please

You will also need some sort of fail safe device in the plug circuit in the event of an emergency

Bob

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Yes you are absolutely right about wooden steamer bearings,Ashley, Lignum Vitae. I dear say the prop shaft rpm would have been a good deal slower though, (Suprisingly, Lynn's work shop at her work is fairly tidy)

Ian and Bob are quite right to be concerned about safety, and we have given this some consideration. On top of a properly engineered servo/linkage set up, we have devised a spring load ignition kill switch. A servo will hold the switch shut, and in the event of radio failure, the spring will pull the servo arm back, open the switch and kill the engine. I have purchased a second hand, but good, 4 channel radio, a mere nz$12, for this model. rudder/ throttle/ clutch/ kill switch. (also the person receiving the boat is a sensible adult)

Happy New Year , Larry- may it be a good one for you!

Lets see, a 14 foot long narrow boat, with a big finer pitch prop, this little engine quietly ticking along at a couple of thou, sounds good to me!

Here's a isometric of the proposed clutch set up, for comment and advice. The only centrifugal clutch we have at the moment is a giant cast iron affair.

[Bob Abell 2Participant @bobabell2]

Hello Amy and Lynn

Referring to your sketch

There are a few points to mention. Bear in mind that this assembly is inclined downwards at 15 degrees

The prop is not shown, but will be down to the left, over hanging the wooden block.

The RH end is not supported and will need to be held in a bush in the motor part of the clutch

The sliding part of the clutch will need a drive key, or a square shaft section…….This, you knew anyway

Can't see a model servo operating the lever, a reversing motor and screw would be better?

A flat faced clutch may work better, as it needs less travel

But a centrifugal clutch would be the best option. I'm sure you could cobble something up?

Bob

[Bob Abell 2Participant @bobabell2]

Thinking about it, a centrifugal clutch would work, but you wouldn't be able to rev the engine without driving the prop

How about a manual clutch?

The engine could idle nicely and move off when required, by engaging the clutch manually

Not bad?……..Bob

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Good morning Bob.

A manual clutch? Glad you thought of it!

A couple of points in reply

The right hand end of the clutch will be mounted directly on the crankshaft. The left hand is fixed to the prop shaft and the entire shaft, prop and all, slides, The cone does three things, 1) support the end of the prop shaft, when engaged, 2) give more surface area for a given diameter, 3) the wedge effect increases the clutches holding power when it's needed most, say sudden acceleration. The down side is it will need a good jerk to disengage, although the moment it does there will be no more resistance. So weather the servo will be up to this I don"t know either, but as the movement required is small, the whole thing can be rigged with plenty of leverage.

[Bob Abell 2Participant @bobabell2]

How will you ensure the clutch stays engaged?

As the servo will self centre

Bob

[shipwrightParticipant @shipwright]

Ashley,

Thank you for mentioning Lignum Vitae (I was unaware of the use of very tough/hard wood in bearings) – you are correct.

Used in marine engineering – even used for bearings in clocks – see :

**LINK**

Ian

[Amy jane SeptemberParticipant @amyjaneseptember49770]

hello.

Bob, the drawing is a little unclear, and could do with a bit more clarification. On the top of the clutch lever is a small eye. The push rod from the servo slides through the eye. There is a cross bar on the end of the push rod, and one further along. These corrospond with each end of the servo travel. This set up also allows the clutch lever to run loosely in the collet, to reduce wear when the clutch is engaged. (remembering that prop thrust is what holds the clutch shut).

Ian, That was a good read, thanks. We tend to forget, in this day and age of comercially made everything, how things where once done! Our native Manawa, (mangrove) is also self lubricating to a certain extent, but the grain is somewhat too coarse for very small bearings.

Amy jane

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Hello again.

Engine bolted in and shaft alignment checked.

Aye, will do.

We have decided to put the clutch on hold, until Bob has finished his most excellent work in the trouble shooting department.

In the meanwhile, Lynn got creative with the arc welder, and an old bicycle handle bar…

I figure it must have been a little tricky, as she sent a very colourfully worded email with the photo. Precise instructions of how to install it, and while I may be wrong, I strongly suspect the rear end she was referring to was not the boats!

The exhaust will exit just above the waterline, which should give it a nice little burble. (yes, the pipe will be well insulated. Hopefully the back pressure wont be too much, I quess we could knock out a couple of baffles, if needed)

The engine removed and another frame cut and added. The next step will be to fair in Bob's rail way sleepers, to the bottom profile, and carve away what's not need on the inside. (The long stick represents the hull's finished length)

[Bob Abell 2Participant @bobabell2]

Ho! Ho! Ho!……It' a cracker!

Got to hand it to you two girls…………You are putting on a really good show and very enthralling!

Well thought out and very businesslike!……What a lovely surprise?…….Proof that women should be on equal pay with the fella's after all!

I suppose, living in the outback, a few hundred miles from civilisation and the nearest chip shop, makes one extra resourceful and inventive!,

Can't make any suggestions regarding the clutch at the moment, except that a manual clutch may be worth considering, with provision for remote activation, later on?

Keep up the good work, girls

Bob with eyes agog!

[LARRY WHETTONParticipant @larrywhetton68737]

Amy ,

still looks like a scrap yard challenge .. but some thing us old uns did with when i use to build stock cars..

good old days …. try to get your woodwork tidy ……….luv Larry…

[Amy jane SeptemberParticipant @amyjaneseptember49770]

Thank you for your kind comments, gentlemen.

The whole resourcefulness thing is a bit of a game for Lynn, she earns good money, (more than a lot of the guys at her work) but only works short weeks.

Progress will be a bit slower now as we are both back at work this week. (blast, got used to being on holiday!)

Fear not , Larry, it will all come together nicely, in due course. I promise!

Aj & L

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