Hi Duncan these are the build instructions for Bruma I printed off. All 13 pages.

https://www.astramodel.cz/manualy/mantua/kr-800736_bruma_man.pdf

Hi Duncan I have had a response from Gupi. He will take photos next week and post them on to his build log.
He did say that he extended the rudder with an allendage for sailng.
regards
Roy

Hi Ronald I suppose I was for a time at the other end to you. I worked for a large UK computer company started as an engineer and went on to management.
Each year I would take on 6 Industrial Trainees for a well paid 12 months who were doing Computer Science courses and introduce them to "The Man/Machine Interface".
I did this for 3 or 4 years and met some lovely young people. Many similar in age to my own children. This was in addition to my P.M. work.

The interesting part was, I was sent the CV's and I knew about massaging such documents, we were past masters at it ourselves!

I was working on a large secure site, a government contract etc. So I had a long corridor to walk along to get to security.

The return trip with the applicant, which took a long 5 minutes was the interview as far as I was concerned! The sit down bit was just to see what else might surface.

My main question was what did you do in the holidays? Quite often got to the real person then.
The ones I took on, I made sure enjoyed their time with us and had several different areas to cover.
I soon realised they loved competition and I only did the real thing. Typically was giving them an idea on how to sell. A lot of our own company buildings had units using in house computer equipment and no contracts for repair!!! Why should Customer Services pay while they had a budget to cover this.
They all had a go at visiting and selling contracts, after all it was a safe environment, and after a few weeks I would total up the value of the contracts and announce the winner. The rest were all "Runners up".

On another occasion I worked with one of the Industrial trainees and we set up the internal help desk for the Automobile Association, where they handled all their IT faults and passed H/W on to our company.

I insisted that the unit we were instructing knew how it all worked and first we did it manually with old fashioned T cards. Should the computer go down they could switch straight to T cards and no one would be any the wiser.
When they were happy we installed the PC and S/W. The system was still running 10 years later, even I was surprised

Loved it, and felt privileged to be have been involved and it was nice when several came back to see me after they had graduated.

Nice memories thanks.
Roy

Best thing about having laser cut wood parts is that they have to use good quality ply for the job.

I think some of the wood I have seen in a few boat kits was of such low quality, I was surprised they used it.

The carbonized edge seems to be going now as well.
Roy

Hi I can echo what you have said. I have a laser cut marble machine to construct. Just deciding how to mechanise it.

Roy

About now would be a good time for her to choose some lottery numbers for you.
Roy

Hitch Hikers Guide.... a great book.
Roy

Hi as far as actual practice goes I usually fit a high quality (gold plated) connector on the end of the aerial so I can unplug it easily. This leaves the aerial in the boat secure and unobtrusive to the eye.

I do have 27 FM, but mostly AM and 40 Mhtz AM and FM,bit mainly FM. And crystals galore.

My reason for not going to 2.4 Ghtz is that I have radio for more boats than I can ever build, so all rx's are dedicated. But it is best to leave a note inside the boat as to what colour or number it is.
Roy

Hi as a regular user of 27Mhtz the usual length of the rx aerial is 30 inches, it is not critical just do not leave it in a screwed up bundle. I make sure that 10 inches or so is vertical.
I check that all is working with the Tx aerial only partially extended.

The main advantage the 27 and 40 Mhtz have is you can poke your boat with the aerial. Not possible with 2.4Ghtz!

However do put a practice golf ball on the end to save others eyesight. You are supposed to have a frequency flag as well.

Roy

Just read the notice it only mentioned "electric powered speed boats".

For me that does not include scale model ships or say you can't have steam power either.

I wonder who enforces the rules? If you launched a non-speed boat but electric powered will you be stopped?

I would try the slow boats first and then try launches but not the fast ones and see how things go.

Roy

Yes I agree were aircraft carriers mentioned there as well? Keeping the lads happy is essential in todays armed forces.

With the recent programme on the UK aircraft carrier the TV concentrated on one 'jack the lad' as their guide, hmmm I was not so sure! Later it transpired that the Navy was not so sure either.
Rather illustrates how the media can be misled or misslead.
Roy

Hi Lewz, You seem to be in touch with the authorities, who are objecting to your use of the lake. May I suggest you offer to meet their representative with a selection of your models at the lake and demonstrate your models.

Many people make legislation or will not adjust the rules from a distance. Most expect a worse case and are unaware of how quiet the models are or how attractive they are for the general public to watch.

In the U.K. insurance and risk assessment are the big worries for the authorities mainly due to the high cost of other council activities, and just saying No is easy.

I had this problem in 2005 when we were being told we could not use the lake at the Park. It was called the Model sailing pond!

Myself and our Chairman got the park manager to the lake in the way mentioned above and he could see we were generally an older and responsible group with sailing boats and scale models.

We agreed with the existing speed limit and most these days do not want the bother of i/c engines.

We had also created a Risk Assessment document outlining what we were doing and what we would do to have a safe activity for members and observers during a sailing session.

Be aware that being knee deep in water was regarded as a safety hazard here!

Look at all 'hazardous' situations and come up with solutions or safety proceedures.

Can you monitor the sound models make in decibels? Have a limit on this noise level, which is published. I suggest some comparative noises and the decibel values to illustrate.

Lastly have insurance for the activity so there is no financilial risk to those making the rules.

We have these measures in place and have the use of the local lake.
It is best to do all of this so that your end is fully prepared from the outset.

A good course of action is not to ask permission!

But ask what regulations and objections are there to stop you from sailing your boats. Make the other side quote the problems as you may have already considered them. Remember that car parking may be objected to as well.

Make sure you have an organised group with a responsible contact for the authorities, hopefully your Chairman.
In the UK it is a good idea to register your club or society with the local authorities, so that you have a public face and known address for contact.

If you run a web site keep contact addresses and Officers under anonymous titles so that messages will get to the people concerned. This will avoid to some degree the people who like to insult and annoy over the Internet.

If you have a web site keep it updated and answer questions etc.

Hope this helps.

Roy

Hi good idea, have you been out on the water yet?

I have several 12 -18 volt motors the size of a 550 and run them on 6 -7.2 volts and they will turn over a big prop 45 - 50 mm.

This looks good on a cargo ship where you can almost watch the prop turn over. They do not get hot and have a low current drain. Bonus is they are often cheap! Also I can use slightly cheaper NiMh batteries of about 3300mAhs.

I have a few Pittman motors originally scrounged out of computer tape decks 40 years ago. They are almost silent and work really well.

I always check for hot batteries or motors as I do not want current diverted from the motor to heating up the drive train.

Following a friend I have also found a cheap and effective and silent U/J. It is plastic flexible tubing about 3/8ths inch diameter in less than 2 inch lengths.

You can use it in place of the Huco U/J, keeping the brass inserts on which it is a tight fit. Or if you have a threaded shaft a largish pair of nuts locked together with the tubing forced over them.

They need to be in a straight line and a few fast forward and reverses settles the tubing into position. The drive is silent and efficient and good for up to 20 watts or so.
regards
Roy

Hi if the Graupner 400 is anything like the MFA 380 then it is a 40 watt motor. Rather a lot of power for your dory. I would guess that when you use your throttle that from half throttle to full throttle there is not a lot of difference in speed.
I have suspended experiments with a similar motor in a 16 inch Huntsman as it just tries to climb up a wall of water. Not sure if it is weight balance or what.

As you surmised originally, a smaller prop and I note the motor has a 6volt marking and 7.2 volts is 20% over voltage. I agree reduce the load and you will get a much longer run-time as well.
Good luck.
Roy

Hi as far as your hot motor goes there is a rule of thumb if you can measure the stall current of the motor. It is very likely that the most efficient speed of the motor is just 20% of this figure. The motor should then run cool.

I expect you are right, the prop is too large or the pitch too great all this would increase the load on the motor. Also as there would be less heating of the motor, the current flow doing the heating would be directed out of the back of the boat where it belongs.

Hope I am not teaching grandma to suck eggs!

regards
Roy

Apparently tack has 2 meanings, 1, the lower corner of the sail next to the mast, and 2 where tacking is going through the wind to set a new course so you are on a new 'tack'.

The clew being the other lower corner of the sail, but it is not a line, just a part of the sail.

I got it wrong so did not have a clue about the question!
Now back to working on my 10th. yacht, where I am introducing a fore-sail having reduced the sail areas of the main and jib.

I think I can work on the mast now the glue has gone off. I have to file a slot in some tubing to create a heel for the mast to stop it twisting. This fits onto a thin slotted rail in the keel of the hull.

Regards
Roy

Hello Duncan. My information is the motor kit is very noisy, and looks to me to be over priced.

Having 2 motors is no problem I use very small chinese esc's they used to cost £2.50! If you also buy a mixer which allows you to plug the esc's in you can use 1 channel to run both motors and the rudder control will adjust for independent speed control, with the throttle controlling boat speed.

I suggest a 5 pole (low powered) 385 motor which runs on 6 volts. I did not like the kit props which are a bit crude and I will be using some smaller 3 bladed ones.

I have been hearing the kit is not currently in production.
regards
Roy

Hi Duncan I think the guys on the forum like to know what is going on. I followed your contact on the Rcgroups and assembled his build blog on Bruma.
A shame no photo of the keel but like you, I have sent him a message to find out if he has a picture of it.

Thanks very much for the link contact, his Bruma looks great sailing under sail!
Personally I think there is too much overlap with fore jib, but easily remedied. If you look on my harbour you will see Pelican which was a conversion from a different sail arrangement.

I feel quite inspired now to make Bruma a model under sail as well. So thanks for the information.
kind regards
Roy

Hi Dave we seem to have been through the same learning curves! I remember the little round servo chip in the Pompey cct, I put mine in a small tobacco tin and used the tin as a heat sink.
I lent it to a friend for his boat and he used it a lot then sold it to someone else! Goodbye ESC.

The relay switch, I think someone told me the idea, and I drew up a cct. The transistor that called the relay was across a resistor and when the resistor got to have 0.7 volts across it it set off the relay.
I used to enjoy those experimental days.

The last cct I put together, afterall you take a bit of this and a bit of that and join it all up! It was for the water level controller in a steam boiler for a model boat, all put together for a 24 hour endurance contest. That was in 1988, rather a while ago now! All published in Radio Control Model Boat builder, also gone now.

However there was a spin off from that cct as I developed it to work in a small steam supplier as used in bakeries and they sold into Safeways Supermarkets. I think Morrisons took them over but a long while ago now.

It seems that most things have been put together for you to buy now and as you say the components would cost you more than the finished article.

The BEC I used to make was a cct I found in the Model Cars magazine, still got it somewhere. The beauty of it was that it limited the i/p voltage to 0.7 volts plus the zennor diode value but it followed the voltage down rather than cutting off dead as does a one piece chip.

The last bit of electronics I bought was a DC Buck converter from Components shop. Works great
regards
Roy

Hello CDN...... first If it were not for a few of us the thread would not give you a reason to complain. I never complain.

Second:- No never surprised when I get it wrong.

Third I should have added to previous post I broke the mast on a yacht I am making and not only was the paint drying but the glue as well. Very dodgy re-glueing masts as they have to be straight as well to carry the sails. I have made one additional sail that was 2 days ago but then shopping etc intervenes one has to prioritise.

So now not happy with paint colour, I am off to workshop again. Then back to cook lunch for 2.
Good luck with the questions
Regards
Roy

Hello Duncan. I bought the kit a month or so back as I realised that when I go to a model boat show I always look out for a Bruma. So thought I better get one while I can.

My first thoughts also were would she work as a sailing boat? I think she would, as there is just enough sail area but she would need a sailing keel.

I did some calculations as I would want to have the same waterline. Motors and batteries have to be at a minimum weight, you only need about 6 volts at 1 amp per motor and the rudder would need to extend down a bit.

The laser cut frames and keel are nicely done but care would be needed in fitting a small sailing keel. I think as small as 6 inches deep by 2 inches wide and a bit less than 2 pounds of lead. There should also be allowance to remove the keel and sail as a motor boat.

I would need to have the hull finished and see where the centre of lateral resistance was. As the sails are fixed in position. The alternative is to guess and if wrong make another sailing keel. The sail winch / arm servo could easily be a standard size but more powerful servo.

Anyway I have another yacht I am working on, just putting up a new mast sail arrangement then finish off a small project then I will begin work on Bruma.

By the way I found a much more detailed set of building instructions on another web site.

I would be very interested to hear your ideas.
Roy

Hi Rod I used make my own esc's when they were relatively dear. Based around the early servo chip, forgotten its number now but no longer available. You said you wanted a fwd/rev brushed motor cct?

There are a number of circuits based on the 555 chip but these are not that stable and prone to interference.

Have you tried a search for a cct? After a few minutes I found several. I do not make them anymore too much strain on the eyesight.

I used to use high quality 16 amp contact relays for the reversing ccts and before that I used the big OC29 or 35, you needed 4 of them connected like an H with the motor connections across the middle.
However you lose 1.4 volts across each transistor pair and you need a heat sink.

The Electronize kit used the big transistors if I remember correctly and they were very good. I moved to these kits and made them up myself.

I have used FET's but only as part of a kit and with only a 0.1 volt drop across a FET no need for a heat sink.
I designed a simple additional cct. which depended on the current going through the o/p power transistor. It was a small transistor with emitter and base across a resistor.
When the the circuit was at max current the small transistor conducted and called a relay which switched the drive motor directly across the drive battery. This effectively disconnected the power transistors and saved on very hot heat sinks.

You may also need a BEC cct I can probably find a cct for this. It uses a zenor diode and a small power transistor. Probably all superceded now as my electronics stopped just before surface mounted compnents.

Good luck
Roy

EXCUSE ME! I am waiting for some paint to dry!!!
Roy

Now our Swiss friend has posed a sentence for ther fast readers. After all the ships' crew is a different proposition!
Maybe I will read that one again?
Roy

Ah yes but was the answer the question or was the question the answer?

The Spanish are far better at putting the question. The Spanish Inquisition had got it to a fine art -form. Here you did not need to know the question before the answer sprang to mind!

That may be stretching a point but you see what I mean.

Roy

Today's question was the most confusing yet. Neither Titanic nor a sister ship as an optional answer.
With a sailing ship the engine is the sail so could it have been the mast?

As I get older the world gets more confusing, was this an A.I. question?
Roy

Hi all, one of the interesting side issues is deciding you do not agree with the answer and researching the "right" answer.

It opens up a whole new path in learning and possibly new angles on teaching.

I have come across a system where MSc's and similar are assessed over time by peer marking. It removes the competitive nature and introduces the agreement on the "right" answer. After all knowledge is the key, not winning a competition.

Something similar to this happened in the model boat fraternity about 25 / 30 years ago. The trip around the buoys and competition suddenly went out of favour and friendly regattas took their place.

I think we are all keen to see how well some things can be done and are pleased at the outcome of others. I am always keen to look inside a working model to see another's idea on operating systems.

My second RC boat had an "engineers" panel so I could isolate the radio side and make sure the rest worked. It really illustrates the radio problems of my first boat"!

I for one have been on an interesting learning curve with previous questions on several different subjects. I think the last few questions have put all into perspective for me now.

Who said you are never too old to learn?

regards
Roy

I am beginning to miss having Titanic as a possible option! So as there was no Titanic I opted for a sister ship. It is easy when you know what to look for.

I thought the whole point about one of the answers was that she was found on top rather than underneath the waves. I imagine the loss of life was still a factor though.

However the warship is one of those 'not hard to find' shipwrecks with a barbette still above the water.

We are all still game so keep em coming.
regards
Roy

Me too but I could not believe the premise of a popular dive place.
Roy

Interesting how this came up to be a question!
Roy