After sitting in the bath to consider the motor problem I have come up with a neat solution which looks as though it will work, but only just. I have a Graupner 900BB torque motor in my TID tug which is vastly overpowered. Consequently I plan to use that motor in Shemarah with an MFA 2.1:1 reduction belt drive to a 75 mm prop. I plan to buy a Graupner 720BB torque to refit in the TID driving its 55 mm prop directly. This has the added benefit of giving me another motor/prop combination to add to my data base (and also Colin Bishop’s). After ringing around suppliers I found 720BB torques are also in short supply but I have managed to find one and its in the post.

 

All the frames are now cut out thanks to my daughter who decided she wanted to strip the wall paper in the dining room which gave me a bonus few hours in the workshop. The next job was to line them all up in packs of about 5 at a time and cut the slot for the keel.

Its great to hear from you and I am delighted that you are planning to follow the progress of my Shemarah build. I have been considering building the model since I first saw the article in Model Boats magazine about 18 months ago. I have had a look around at quite a few model boat shows since then, to see if anyone else has built a model of Shemarah II but so far I have not seen one. I have seen some photos of a model on one of the trawler photo galleries but it looked as though it was a bit smaller than the one I am building.

 

The plans are very detailed so I don’t really have any excuses for getting anything wrong. However when I reach the stage of doing the wheelhouse and deck fittings, some photos of the real vessel would be very usefull. If you have any, or would be able to take some in the future I would be very grateful. Jim Pottinger’s photos in the original article will be a big help but they are pretty small and it is often difficult to understand the detail of the equipment. However I do not usually build my models very quickly so it will be at least six months before I get near that stage.

 

I hope you find the story interesting and the finished model does justice to the original. Having the real vessel’s skipper following the progress of the build will give me an added incentive to get on with the job,

 

Best wishes,

Gareth Jones

 

 

 

Thanks for the advice John, I am still pondering which will be the best way to plank the hull. There are some very large flat areas and my first thoughts are to cover those with 1.5 mm ply sheet. The rest I am not sure about yet but my original plan, based on a quick survey of the web, was to use 1.5 mm lime planking. Either way I will be adding a number of stringers as you suggest. I was also planning to cover the exterior with resin and glass cloth or tissue to waterproof and strengthen it. I will also coat the inside with resin. When you diagonally planked your hull with 0.8 mm ply did you use a single layer or two?

 

The plans are by James Pottinger, redrawn by Dave Metcalf. They are very comprehensive and easy to follow in showing the details of the original vessel and the lines of the hull. There is no model construction information so I guess it would not be a project for a complete novice.

 

I have reverted to my original profession today and done a bit of systems engineering. I have robbed the Graupner Speed 900 BB torque from my TID tug and mated it to the MFA belt drive reduction gearbox that I got for my birthday on Saturday (62 if you really need to know). This exercise was not without its problems, one expected, the other unexpected.

 

The first picture below shows the motor and gearbox fitted roughly in the proposed position in the hull to get the line of the propshaft and the second is a close up of the motor.

 

Having just about finished my narrow boat, Walbut Dream I have now been able to devote a bit more time to Shemarah again.

I spent a little time fettling the frames and realised attaching them to the base board with countersunk screws was not a good idea as its gives no scope for minor adjustment. Consequently I have added washers under their heads to give me a bit of scope to edge the frames backwards, forwards or sideways as required.

 

No skiving today to watch the royal wedding, its been a Shemarah day from morning till night. Most of the stringers are now in place, with just one left to do at mid height either side of the bow. The front ones are 6 mm x 3 mm to give a bit more flexibility on the curvy section of the hull.

 

After a short break for Sunday tea here is the rest of todays progress. My eyesight is not very good. With my glasses on I can see from about 2 feet to infinity and with my glasses off I can see from about 4 inches to 8 inches. In between it gets a bit hazy. However the ruler helped me line up the prop shaft and motor to the best of my judgement..

 

Here’s the next area being sheeted under the aft end, plently of clamps and a few pins holding it in place till the glue dries.

 

The next step is what I think of as one of the key steps in building a hull, where the propshaft is finally glued in position. It has to be done at this stage as the next area to be sheeted will restrict access to it. This is the first time I have used a Roboesch maintenance free sealed and ballraced propshaft and I did not find the instructions all that clear. The picture below shows the forward end where the bearing and seal housing sits. As supplied this is free to float on the shaft giving about 10 mm tolerance on the overall length of the tube. It has to be glued to the tube on or before installation to seal the prop shaft. However once glued, in this installation, there is no way of moving the propshaft assembly in or out of the model by more than an inch or so..

 

I fitted the propeller and Kort nozzle and determined the correct axial position for the shaft and then glued the bearing housing to the outer tube using Araldite. The bearing housing is a close fit to the tube so not much glue is needed and the whole assembly stays in line. I then rotated the tube to ensure the glue sealed the whole perifery before leaving it to dry. When it was set I could then slide the assembly about an inch aft to put some glue on the outer part of the bearing housing which sits in the locating plate shown above, and at the stern where the tube enters the hull before sliding it back in and rotating it a few times to make sure the glue made a good seal with the hull. When the Araldite had set, I have to say the shaft does not feel as free as the type I am used to with brass or bronze bushes. This has a Delrin plastic bearing at the aft end and a ball race and seal at the forward end so maybe it should feel slightly stiffer or maybe more viscous would be a better description. However it rotates smoothly with no rough spots so hopefully its OK and with a bit of water in it to lubricate the bush and seal, it should free up a bit. Time will tell but it will be a real ****** of a job if it ever has to come out.

 

Planking has continued with some slightly thicker pins which have proved more reliable. It is quite challenging to try and fit the planks in the best line where they will lie straightest. Provided that the planks are only bent in one plane, the edges stay straight and the next plank will butt up against it neatly. However if a plank is twisted as many inevitably are, the next plank has to be pulled or pushed sideways over part of its length to stay up against the first. I have mainly been using 8 mm wide planks and usually after three or four twisted planks it is necessary to insert a ‘stealer’ i.e. a plank which does not have parallel sides, in order to get the next plank edge to lie reasonably straight. It is impossible to plank the full length of the hull in continuous planks so I also had to try and work out the best places to start and finish groups of planks. All in all quite challenging but somehow satisfying. How well it will all look when its finished is a bit of a guess at present. Hopefully I won’t sand through the full thickness of any planks when it comes to rubbing the whole thing down.

 

Hi John,

 

Thanks for that advice. I am planning to leave the extensions on four of the frames, one at each end and two either side of the middle section, so that I can re-attach the hull to the board when it comes to rubbing down and fibreglassing the hull. However I wanted to remove most of them at this stage so that I can build up the side skins to the top of the bulwark level without worrying about how I would be able cut off all the frames at deck level afterwards, when they would be butting up against the bulwarks. I am going to cut partially through the outer area of the 4 remaining frames so they can be removed more easily at the end with the bulwarks in place

 

The motor and Kort nozzle were only fitted for show at the weekend to give people an idea how they look. Similarly the rudder will not be installed permanantly at this stage, just fabricated as an assembly and trial fitted.

 

I am planning to fill and smooth the hull with Isopon before fibre-glassing. I did toy with the idea of fibre-glassing first as I thought it might bond better to the bare wood than filler but I have subsequently changed my mind. What’s your expert opinion? I have never done this before.

 

One idea that did work quite well at the weekend was the built in provision for a carrying handle (see photo below). It was quite easy to carry around but the hull only weighs 5.4kg at the moment, it will be a bit different when its finished and weighs about 20 kg. Still, I think it will be more manageable than trying to get my arms around the hull and carry it that way.

 

 

Thanks for that John. I think I will try it that way. The only possible variation at the moment is that I have a suitably sized piece of woven glass cloth which I bought years ago to cover an aircraft wing. I might try draping that over the hull to see how it follows the shapes and use that in place of tissue if it seems OK,

 

Shemarah had a few days out this weekend on the Goole MBC stand at the CADMA show. It attracted a lot of interest, so much so that on the second day it was moved to the corner of the stand so it was more accessible to the visitors. If I had a pound for every person that fondled its bulbous bow and bottom I would be a rich man now,