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[Colin Bishop]

When I built the original Model Boats Magazine review kit of Imara in 1989, which was electrically powered, I fitted 45mm props. They were outward turning with plenty of thrust both forward and astern but  the boat totally ignored the rudder (which is why a single screw version was subsequently brought out). Tank steering was the only way to control the boat.

In this case, inward turning screws which force the water against the rudder are likely to be more effective than outward turning ones. It's just the shape of the hull I guess.

Colin

[1967Brutus]

When I built the original Model Boats Magazine review kit of Imara in 1989, which was electrically powered, I fitted 45mm props. They were outward turning with plenty of thrust both forward and astern but  the boat totally ignored the rudder (which is why a single screw version was subsequently brought out). Tank steering was the only way to control the boat.

In this case, inward turning screws which force the water against the rudder are likely to be more effective than outward turning ones. It's just the shape of the hull I guess.

Colin

Those things are pretty unpredictable anyway... We learned some about it in Nautical college, but even then the general consensus was that all rulles of thumb were fine and dandy but no guarantee at all...

[DBS88]

Thank you for the feedback, I had no idea that Imara had been available for so long, its a fantastic model. The direction of prop rotation is interesting, I did do some research before fitting the props, there were two schools of thought, so I went for the set up that rightly or wrongly seemed best suited for a Tug. I am happy to swap them over to see the difference. This is what I had read before I fitted the props - With twin props it depends on the rudder(s). If a single rudder inboard for manouverability, outboard for speed. Twin rudders it doesn't make much difference. (Perseverance has a single rudder).
On a tug viewed from astern there is debate as to which way for the props to turn is best. If they turn outwards, that is the port side turn anti-clockwise and starboard turn clockwise, the vortices or propwash lifts the stern upwards - it wants to ride on top of the propwash. If they turn inwards the stern wants to squat down - it is being sucked lower by the propwash.


The debate is which is best for towing, squatting down means it sets the props firmly in the water giving greater pulling power, but at the expense of possibly pulling the stern lower in the water. If it rides the propwash all of the horsepower available will not be given to pulling the towed item.
It will be interesting to see how the real world transfers into the model world so I will experiment and share the results.

[DBS88]

Anyone who has built an Imara/Perseverence will know that the funnel gets used as a handle for removing the main cabin structure, therefore, its very important that the funnel is very firmly secured to the cabin structure. This is the solution my friend John engineered to keep the funnel bolted firmly to the cabin structure.

[derekwarner]

  ...that soft solder between hex standoffs to the brass strip may get a little warm    atop of the top of the boiler shell Dave..........


Derek

[KNO3]

The new propellers look stunning!

[KNO3]

...that soft solder between hex standoffs to the brass strip may get a little warm    atop of the top of the boiler shell Dave..........


Derek

It's not going to get at 100 deg C or more.

[1967Brutus]

It's not going to get at 100 deg C or more.

Soft solder can significantly lose mechanical strength at temperatures as low as 90 deg C, depending on the solder used.

[DBS88]

Thank you for the thoughts about the soft solder, will have to see if it works, but hope so having taken the time to insulate the boiler.
One of the differences between Imara and Perseverance is the addition of a cabin for the top wheel position, on Imara its an open wheel deck. John sketched out and made a cabin from scratch, there is not a drawing or parts for this in the kit. First photo shows the lower cabin (supplied with the kit) that John assembled, adding for fun extra items, a bottle of whiskey and some posters for the walls. Second photo shows both cabins. In this time wiring for LED lights was also added. The white metal poles for the railings were not used, instead brass poles and wire were used for all the railings. John did a good job of bending and soldering the them into position.

[1967Brutus]

adding for fun extra items, a bottle of whiskey and some posters for the walls.

I particularly like THAT style of detailing: Making it look like tiny old salts lived and worked there...

[DBS88]

Here is a photo of the inside of the newly constructed top wheel house complete posters and with LED light.
One of the big detailed features on the deck is the steam winch so some time was spent trying to make it look realistic, used. I have not painted or weathered models of=r fittings before so watched a few videos and had a go, here is the result. First the white metal fittings were filed to remove flashings from the castings, next they were de greased, then they were prepared with a thin coat of black primer. Once primed, the green, the matalic silver and the brass paints were applied. The finish was too bright and shiney, to new. A thinned wash of black was applied which when dried looks like oil residue and has dulled the finish to hopefully achieve a more life like representation of a steam winch.

[DBS88]

One of the things I have learned from this project is to treat every part, no matter how small, as an individual model in its own right. To clean it, to prepare it and paint it as if it is the finished model. Then when all the well constructed and finished individual parts are brought togeher, they really do stand out. Previously I would have assembeled the parts and then tried to paint the assembly, and then wondered why I was not happy with the finished item, not any more, treating each part on its on has been a valuable lesson for me.

[SteamboatPhil]

Blimey Dave that’s a lot of bits 

[DBS88]

I didn't count all the bits but there is rumoured to be 1400 parts, if true thats a lot!
To bring life to Perseverence, crew figures were bought. The figures were cut out, the excess plastic from the moulding process removed so no visible lines could be seen on the parts. The surfaces to be joined were filed flat so that the joints when glued would be invisible. I have not painted figures before so experimented to try and achieve light and shade on the figures. First they were sprayed black, then to replicate the way the sun falls on an object and lights it, they were sprayed from a high angle downwards with a light dusting of white. 

[DBS88]

Multiple thin coats of the final colours were then applied over the prepared crew figures, with the aim of creating shades of the colour rater than a solid uniform flat colour. The faces didnt go too well, I should have painted the eyes first, rather than last. Like the rest of the model, the aim was to have the crew looking like they were working, not factory fresh and clean.  The crew were then positioned and fixed into place.

[DBS88]

The two lifeboats involved a a lot of work. They are vacuum formed plastic that needs to be cut out, then the top glued to the bottom part. The whiye metal fittings for the oars and rudder needed painting, then ageing so they didnt look brand new. The boats themselves were then painted, ropes with handles were added to the sides, then the boats were attached to the model. John had made a good job of assembling the deck and lowering gear for the life boats complete with the rigging. In fact John did such a nice job, the mechanism would actually work. As you can see from the last photo, the model is nearly complete.

[1967Brutus]

That looks amazing.

The only comment I can mak, is that the location of the oarlocks seems rather strange to me. They usually are placed on the coaming, as any place closer inboard sacrifices leverage for the oarsmen.

The davits/lowering tackle really looks the bizz...

[DBS88]

With the steam plant finished it was run on the bench a few times to bed the engines in, check that it all worked as it was intended to and make final adjustments. Here is a link to a video of one of the tests with the two PM Research No 8 Engines in steam and running on the bench and a photo of the completed steam plant.
https://youtu.be/-rXseq8Mt1A?si=5u-Bnh_bfPzXKLQB

[SteamboatPhil]

Nice one Dave, that is running soooo smooth and clean, and sound good too 

[DBS88]

Phil, thank you, the engines are quite mesmerising to watch, powerful as well. I was surprised how little noise the steam plant made, just the burner and a bit of hissing and the motion of the engines, plus of course the wonderful smell of steam oil. Anyway enough of that I promised to share with you the mistakes as well and when going through some photos, realise I hadn't told you about the decking.
When I purchased the hull a ply deck had already been installed. All John and myself had done was to cut some larger holes in the deck to access the rudder and new wider access created to allow the whole steam plant to be removed. To finish the deck and ensure it was water proof it was cleaned and coated with a very thin epoxy resin, this soaked into the wood, adding strength as well as waterproofing. The resin was rubbed down and airbrushed with a few very thin coats of water based grey primer, this took ages to dry and looked terrible. It was rubbed down and thin coats of the green paint was airbrushed over the top. The problem was probably me being impatient and not letting the paint dry enough between coats, but each coat seemed to reactivate the previous coat resulting in an uneven blotchy looking finish, that not only looked awful, but was not the right shade of green. It would have been better had I sprayed it over a black primer, but probably still too bright. Knowing a lot of the deck would be covered with planking I reluctantly left the awful looking paint to see how it looked after the planking had been applied, after all I wanted a worn working boat finish, maybe it would be ok? - I was kidding myself, in reality, I knew the colour needed to change to a darker shade of green.