Vintage Gentleman’s Cruiser

[Bob Abell 2Participant @bobabell2]

Wow!…What good service

Only ordered the belts and pulley`s yesterday and they arrived this morning!

Deep joy……Are we in for some fun?

The pulley`s are from Motionco

22teeth x 3mm pitch x 4mm bore @ £6.55 plus inc vat

Belts are £3.00 each plus vat

Bob

Edited By Bob Abell on 25/07/2017 14:56:26

[Ray Wood 3Participant @raywood3]

Hi All

The zero angle of Volvo outdrives has solved this problem for around the last 40 years on small and medium sized pleasure boats, and you don't need a rudder and with power trim the angle can be adjusted once your up on the plane.

Regards Ray

[Bob Abell 2Participant @bobabell2]

Is that a water nozzle device, Ray?

I suppose an outboard motor drive also has a zero angle

Bob

[Ray Wood 3Participant @raywood3]

Hi Bob

It's just a stern drive, like an outboard leg mounted and pivoted on the transom with a conventional inboard diesel or petrol engine, much more economical than the big 2-stroke outboards, but they are 4 strokes now because of the pollution.

Regards Ray

[Ray Wood 3Participant @raywood3]

Here you go Bob, this is a posh one with contra rotating props to counteract the torque.

Regards Ray

[Dave MilbournParticipant @davemilbourn48782]

As I am on record as saying, this is all eyewash. Here is a Fairey Swordsman

The shaft angle is about 12° but the boat has no tendency to take off vertically out of the water. The thrust is marginally reduced (by around 2% – do the vectors, Doc) but the practicalities of obtaining a zero degree thrust angle involve using four power-sapping bevel gears in a Z-drive. None of my models has anything like a zero shaft angle and I've not noticed any lack of power or urge to fly. I don't have to fit mind-blowingly long shafts or belts-and-pulleys either. I guess it's a case of do as you like.

DM

[Bob Abell 2Participant @bobabell2]

Why not fill the bows with enough bricks to get the prop shaft to be horizontal?

And see what happens?

Bob

[Colin BishopModerator @colinbishop34627]

Add weight and lose speed Bob, simple really. As Dave says, the shafts don't need to be horizontal to deliver the thrust needed to get the boat on the plane. There are complex hydrodynamic forces at play. The outdrives do give a horizontal thrust but you lose power through the 90 degree gearing so there is a lot of swings and roundabouts involved. Models are probably more inefficient proportionately when it comes to using bevel gears etc.

Overall, like Dave, I subscribe to the KISS principle.

Colin

[Paul TParticipant @pault84577]

Dear All

Dave and I have batted this backwards and forwards for a few years now and we have both had fun in the process but we both know the difference between the purity of design and the practicalities of construction.

I agree that the Fairey boats are the epitome of 1960s powerboat design and represent both grace and speed but I just can't reconcile myself with those dangling propshafts.

The Ellie and VGC designs were partly an exercise in reducing the pitch of propshafts…..which worked but with the double downside of placing the motor further forward of the ideal position and having extra long propshafts.

The RiverCat utilised a perfectly horizontal shaft and had the motor in exactly the right position with short propshafts but the compromise in this design was to place the props within tunnels. Ideal for a fast river boat but not suited for heavy or choppy water.

The best model for purity of design was Mighty Thor, horizontal shafts, ideal motor locations and a perfect heavy water hull.

Is there a boat that demonstrates the true purity of design? if there is I haven't found it but I will keep on looking.

Paul

[Bob Abell 2Participant @bobabell2]

Chain drive mech to the Rudder

Makes an interesting alternative to the usual Push Me, Pull me mechanism

Bob

[Bob Abell 2Participant @bobabell2]

Cobbled the motor drive together for a trial run, using the old faithful Rheostat device

I can only say……..WOW !

With a potential of 20k on each motor………WOW again !

I like the motor drive idea, it adds interest at the pond side

Had a stroke of luck this morning…….The motor has a 1/8" dia shaft and the propshaft is 4mm

Found a length of brass tube in the scrap box that fitted perfectly

A fine start

Bob

[ashley needhamParticipant @ashleyneedham69188]

Bob. I have to admire your inventiveness. You are a true engineer: An engineering solution just for the sake of it and blow the practicality!!

Keep up the good work.

​As I type I cannot remember the gearing ratio….was it 1:1?? Those high speed motors should be geared down to about 3:1 I reckon to turn a decent sized prop… a nice big X50 or something ????|

​Ashley

Edited By ashley needham on 27/07/2017 22:14:43

[Bob Abell 2Participant @bobabell2]

Many thanks Ashley………..You like a bit of fingers crossed complication too?

Don't fancy changing the pulley ratio at the moment

I would think that a change in pulley size would have the same effect?

Have had a 55 dia prop on and it looked OK to me

A couple of 50's from Haydock will do me

Bob

[ashley needhamParticipant @ashleyneedham69188]

Bob. It is what the hobby is for. Make stuff as you like it. You and I, and others do it for fun, there does not have to be any rhyme or reason for doing things as you do.

Part of the beauty of your builds is the unnecessary complication ! I like it.

​Seriously, if those motors are about 540 can size, you should gear them down a bit or fit small 30-40mm props. A change of pulley sizes will do it of course same as changing sprockets on a chain drive. I bigger prop will be much better for a boat that size and weight, as I have a feeling that small props would just create froth and not much else.

Ashley

[Bob Abell 2Participant @bobabell2]

Ashley

If I`d gone the normal route and simply fitted a shaft coupling between the motor and the prop shaft

Bang goes the 3 : 1 reduction idea………Eh?

I`m keeping the equal pulleys and going for 50mm props and steady as she goes

Bob

[Paul TParticipant @pault84577]

Design Office to Chief Engineer

Out of curiosity I had a look at the original design calcs for motors / props for this boat and found that I had calculated a single MFA 800 with a pulley gear drive for slow turning a 50mm 4 blade brass prop as the hull was never intended to create a large bow wave but glide through the water.

However there is nothing to say that your set up won't perform any differently so it will be interesting to see how your 2x 550 and 50mm props work with this hull.

Paul

[Bob Abell 2Participant @bobabell2]

Hi Chief

Got both motors properly connected up now, but the other batteries are in the garage and it`s chuckin` it down at the moment!

I`ve screwed the motor mounts to the hull sides securely from the outside

Unfortunately, it`ll be some time before we get in the water

Bob

[Bob Abell 2Participant @bobabell2]

Nothing too exciting

Just fitting the deck edging and making use of the bow clamping device

Bob

[Bob Abell 2Participant @bobabell2]

Latest situattion

Motor drives and Rudder Mech finished and signed off

Now working on the superstructure again and spotted that the funnel is not shown on the drawing?

Bob

[Paul TParticipant @pault84577]

Bob

It should have four funnels but one is false.

Paul

[Paul TParticipant @pault84577]

Bob

This is a little off topic but I just had to warn you against the latest home gadget.

I don't know how these thing have caught on….. absolute agony and quite disgusting to use. Call me old fashioned, but I'm sticking with toilet paper.

Paul

Edited By Paul T on 01/08/2017 18:04:02

[Bob Abell 2Participant @bobabell2]

Hi Paul

Is it a Toothbrush?

Bob

[Dave MilbournParticipant @davemilbourn48782]

Is it a Toothbrush?

Only if you get to it first…..

DM

[mike farrellParticipant @mikefarrell21522]

Hi Paul

Just to let you know that item is only for women , so keep your hands off LOL

[Colin BishopModerator @colinbishop34627]

A bit too much off topic for you Vintage Gentlemen I think!

Colin

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