Vic Smeed’s Silver Mist

[Chris FellowsParticipant @chrisfellows72943]

Robust is the only way I know how to build!

Some of my keels with doublers are 18mm ply!

Chris

[Colin BishopModerator @colinbishop34627]

Got diverted over the last few days but now have a couple of planks around the top of the hull. Now need to remove it temporarily from the base support and add some along the keel.

Colin

[Colin BishopModerator @colinbishop34627]

I have now planked enough of the hull to be able to confirm the feasibility of twin screws and cut out the slots to accommodate the tubes.

Looking at placement of props on similar ‘Silver’ motor yachts there is not very much clearance for a scale appearance. Vic of course used a single prop at a sharp angle but I needed a more horizontal setup,

The original vessels featured bare shafts after the tube emerged from the hull with a strut support at the prop. This seems a bit over complicated on such a small model but the 6mm OD Caldercraft Fineline tubes still looked too big. However, Model Boat Bits do a range intended for motorising plastic kits with 2mm shafts and 3/16 in (4.78mm) tubes which will look acceptable.

I still need 10 inch tubes to get sufficient rise inside the hull to connect with the two 385 motors though.

I will be using 20mm three blade props which should be OK on a 7.2v NiMH pack.

Colin

[Ray Wood 3Participant @raywood3]

Hi Colin,

I’m drawing a  26″ Slipper launch which shows the shaft being supported with a P bracket and little skeg, but I’m going of the full length tube & shaft as you are. As I have had all sort’s of stuff wrap round an exposed shaft 🙁

Regards Ray

 

[Boiler BriParticipant @boilerbri]

OH that’s interesting. I have just fitted two exposed shafts on the Pilot 40. I hope that they don’t give trouble. I suppose the water that we sail on will have a big effect on the rubbish that’s picked up?

 

Bri

[Boiler BriParticipant @boilerbri]

[Colin BishopModerator @colinbishop34627]

My Fishery Cruiser has exposed shafts.(photo below). As you say, it depends on how clear the water is. I have just gone for simplicity on my near scale Silver Mist.

Colin

 

[Richard SimpsonModerator @richardsimpson88330]

When you think about it, in real practise, if there is a significant distance from the hull penetration to the propeller there simply is no justification to completely encase the shaft.  Most will have a stern tube on the hull and then a ‘P’ bracket or an ‘A’ bracket just forward of the propeller.

Interestingly nowadays the shaft is frequently wrapped in fibre glass for protection.  Some shafts use a plastic bearing either end of the stern tube and in the ‘A’ bracket, which is water lubricated and cooled.

For some reason or another the forum will not allow me to upload pictures at the moment.  Anyone else?

 

[Richard SimpsonModerator @richardsimpson88330]

I remembered!  The forum cannot handle very long file names!  Here are the pictures I was going to attach in the last post:

 

 

[Richard SimpsonModerator @richardsimpson88330]

I know some modellers who converted the Revel Type VII U-boat to RC used long stern tubes to cover the exposed shafts but to me it just didn’t look right.  I do restrict using mine though to fair weather, as the deck isn’t sealed, and clean water.

[Colin BishopModerator @colinbishop34627]

No, it doesn’t look right on a scale model but Vic’s Silver Mist hull was designed from photos taken from a passing boat he was on so the model is semi scale at best. His single screw solution was dictated by the available kit at the time and even then he had to  fit the shaft at a sharp angle to marry up with the shaft of the recommended Taycol motor.

I have only achieved a slight shaft angle on my model by using 10 inch tubes to meet the two 385 motors.

In his build notes, Vic states that his model is no more than a representation of the original Silver Vanity he saw which gives me quite a lot of scope for above deck detail based on images of similar ‘Silver’ boats.

Some of the full size boats had three arched windows in the hull which I think look better than the combined glazing frame on Vic’s plan

Colin

[Ray Wood 3Participant @raywood3]

Hi All,

Only my view but I think Vic’s design actually better than that one 🙂 , although having looked at for 60 years may have been the reason, that added on shelter behind the wheelhouse looks like an American express launch idea to be me 🙁

I’m sure parts have been added over the years to make the boat more useable , is that a shed on the rear deck ??

Regards Ray

[Colin BishopModerator @colinbishop34627]

Hi Ray,

That particular boat has been extensively modified, mine won’t have the extra superstructure. As far as the windows are concerned the  ‘Fairey’ like metal frame does contrast with the varnished backing. Whether that is a good thing is a matter of opinion.

The photos below show a 68 foot version with Vic’s window design which appears to have had the extra length inserted abaft the wheelhouse to allow for an on deck saloon.

It does look like the boats were built to order on a basic hull and forepart design and, as you say, many have had the deck structures subsequently extended in various ways.

Colin

[Colin BishopModerator @colinbishop34627]

Now getting on with sanding down the hull, I will fit the softer balsa blocks to bow and stern afterwards.

The shafts, one prop and some smaller items have arrived from ModelBoatBits and took only 4 working days which is excellent service. This has enabled me to roughly position the running gear as the photos show. It has also suggested a possible rethink on controlling the boat.

I had intended to rig up microswitches to cut out the inner prop on a tight turn but the props are actually quite close together against the keel and this won’t give much leverage. On the other hand, if I fit a fairly large rudder and have the props inward turning then the rudder should deflect the propwash and directly push the stern around.

Colin

[Richard SimpsonModerator @richardsimpson88330]

Do you not fancy tank steering Colin?  With the rudder as well of course.  It just gives you total flexibility with independent shaft control.

[John W EParticipant @johnwe]

hi ya Colin

following the build with great interest – are you building your model the same size as the plan?

have you thought (and I know you are not a fan of purchasing Chinese made stuff) but, I have a couple of these twin speed controllers from Amazon and they have the mixer built in.   Or, you can modify them to do tank steering – going to try and put a link on for you.   I am using one in the model of Bloodhound which I built and up to now for £14 it is looking pretty good – running two motors on 7.2 volts.   When I had the model in the lake the other week – there are no signs of any heat coming from the speed controller, even though the motors were a little bit warm.

John

http://Dual Way Brushed ESC 18A x2 Mixed Control Speed Controller for RC Cars Boat Tank Z zheng_424http://Dual Way Brushed ESC 18A x2 Mixed Control Speed Controller for RC Cars Boat Tank Z zheng_424

 

[Colin BishopModerator @colinbishop34627]

It is a very small model Richard and I would need two ESCs. As I mentioned, the props are close together but the boat has a low length to beam ratio so minimal leverage.  It is intended as a bit of a cheapie project using up stock so I don’t want to overspend on it.

My Fishery Cruiser has a setup where I can switch between both motors together and tank steering by simply flicking the undercarriage switch oh the TX. It is able to do this as it uses old fashioned ASTEC Escs with relays that don’t mind being switched off and on momentarily. Doing this with modern autoset types causes a reset which can take a few seconds or interfere with the electronics. Some times the old ones are best.

Anyway, I am one of those people who think that tank steering is best left to tanks when generally sailing around the pond, only useful when manouevering at close quarters. I have tried tank steering and find it difficult to maintain a smooth course with a standard TX. You need one of those old Robbe Navy TXs with the throttle levers grouped together to get the same functionality I have with my Fishery Cruiser.

Of course, in real life, full size ships would only steer on their engines if the rudder was out of action and by all accounts it was a tricky process.

Colin

 

[Colin BishopModerator @colinbishop34627]

John,

That is a nifty little device, I will keep it in mind. It may come in useful for my liner models if I get round to finishing them although I have a couple of Action P94s available and the models will take the extra weight. I have been impressed with the Quicrun ESCs from Howes and elsewhere, one of which is in my Greek Fishing Boat.

At the moment I have been afflicted with the simplicity bug, probably because the plan dates back to 1958 which is only 10 years younger than me! I can in fact hedge my bets as if he rudder doesn’t do the job then I can initially revert to Paul Freshney’s method. He could never be bothered with mixers and just stuck a couple of switches over the rudder servo to cut out the inboard motor on a tight turn. He swore he only had to apply a bit of practice to get the results he wanted and he won a good few awards.

Yes, I am building the model to Vic’s plan, 21 inches long, amended to take twin screws but intend to garnish the upperworks a bit in line with photos of other James Silver motor yachts of the period.

Colin

[Tim CooperParticipant @timcooper90034]

Colin

Do you mean the Robbe F14?

I have one of those. Makes the Rx you have to use expensive. To use the extra add on functions you the need a decoder as well.

Tim

[Colin BishopModerator @colinbishop34627]

Tim,

Yes that’s right, they were very expensive in their day. I believe at one time you could buy the twin throttle assembly on its own. If so it might have been possible to fit it to a standard TX if the resistances were similar.

Many years ago, when the wheel broke on my Futaba M series Steerwheel, TX I transplanted the wheel unit from a cheap Monza pistol car TX and it worked perfectly. I still have it.

Colin

[Tim CooperParticipant @timcooper90034]

Colin

I think it was about £150 but without a battery.

RX was another £40+ and the decoder plus the switch unit extra again. I don’t like to think how much. Luckily this was when I was working and we had a bonus once a year.

When I built my Graupner Bernhard Gruben I bought a 9 channel Radiolink for £90.

Now I could probably do it for less than that.

Although I have trouble moving my big boats now.!

Tim

[Colin BishopModerator @colinbishop34627]

Although I have trouble moving my big boats now.!

 

Yes, me too! Hence Silver Mist!

Colin

 

[Ray Wood 3Participant @raywood3]

Hi All,

My big mistake on MS Oldenburg was to fit a single rudder behind the twin screws, this was mainly because I hadn’t seen any pictures of her out of the water ! the ships Chief Engineer soon put me right 🙁 Ooops

The single rudder is a good as a chocolate tea pot !! probably gives it a 20 foot radius turning circle which is interesting at time ||

Cruiser sterns are a nightmare for rudder linkages !

Regards  Ray

[Colin BishopModerator @colinbishop34627]

Ray,

Yes, the shafts on Oldenburg are too far apart for a single rudder to benefit from propwash. I had the same problem with my Caldercraft Imara. Tank steering was essential. The manufacturer subsequently brought out a single screw version to address the problem.

On my Silver Mist the props are much closer together and the propwash will impact directly on the rudder which will hopefully be effective. If not then I can still go down the limit switch or even John’s nice little mixer route. I can hedge my bets.

Colin

[Colin BishopModerator @colinbishop34627]

After adding the bow and stern blocks and a lot of rubbing down, the hull is nearly ready for skinning with glass cloth and resin. I will use EzeKote on the outside as it is less messy than finishing resin.The interior will be given a coat of Z Poxy finishing resin to add strength and watertightness although the exterior should be waterproof anyway.

The mid body shape of the hull is determined by the bulkheads and Vic’s drawing gives fair lines. The blocks were a bit trickier as there are no templates, the bow was easiser but the stern needed more work. It is always handy to be able to take off the hull shape to make checks using the commercial gauge and I also have a very handy strip of sheet lead which is both quick and accurate when pressed against the hull. Best to wash your hands after using it though and don’t let it literally get into the wrong hands.

I have still to work out the precise placings of the shafts and rudder and modify the stern deadwood if necessary.

Colin

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