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>> Home > Boat Building Blogs > H.M.S BRAVE BORDERER
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Author: RHBaker   Posts: 16   Photos: 30   Subscribers: 1   Views: 2621   Responses: 50   |   Most recent posts shown first   (Show oldest first)

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HMS BRAVE BORDERER - Posted: 21st Sep 2018
Adjusted the transom flaps and reprogrammed the ESCs to the softest start settings, retested. Until now, the test runs did not have the duration or stability to really examine what was happening.
Using 3 S batteries acceleration is rapid and a is plane quickly achieved. However, as the acceleration continues and speed increases, the bow digs in. A cloud of spray then surrounds the model as the plane is lost. Brushless motors do not modulate as smoothly as brushed and adjusting power tends to be erratic or exaggerated.
This is a scale model and the propeller shaft angles are per the plans. The thrust from the propeller has two components, horizontal and vertical. The horizontal propels the vessel forward. However, the vertical component forces the stern upwards and, correspondingly, the bow down. Have moved as much weight as possible towards the stern to counteract this, limited by maintaining the correct displacement and waterline. The easiest solution is to reduce motor power, decreasing both speed and the lifting component.
Decided to retry the 2S batteries as they give reduced power. A plane is again achieved, but as the motor response is more docile, it can be controlled. If the speed gets too high the bow lowers, as before, but the motor output can be more easily adjusted.
Spent a pleasant half hour or so with the vessel accelerating onto and off a nice, controllable plane. Much less spray and drama than with 3S and much more controllable.
Have now decided to revise plans and use 2S rather than 3 batteries. A further advantage is the motor noise is muted and now sounds more like a gas turbine than a dental drill!
Finally feeling comfortable with the model. Will thus shelve further building until the late fall when sailing in Canada concludes. Want to enjoy the rest of my fleet in the meantime!
Will summarize my experiences with brushless motors in another blog shortly for the benefits of others contemplating their use. After restarting the model will resurrect periodic build blogs to advise progress.
Response by RHBaker on the 22nd Sep 2018
Boaty, that is one of my suspicions. My Brave is to 1:32 (about 37") whereas most seem to be 1:24 (about 54"). Am sure 3S are fine on the larger models, but on mine think they overpower it.
Response by Lyle on the 23rd Sep 2018
I suggest you go to one of my old reports on my 48 inch Crash boat by Lyle G. The issue is most likely t5hat asn it is a MODEL it needs some extra support in full size water . A model thus NEEDS the advantage of planing strakes at the vertical hull and lower hull joint as it is a "Hard Chine design " and you may need to widen with an extra strake WIDTH though it can be thinned in its vertical configuration as it is blend into the forward hull skin. The wider chine is the secret of the MGB's Torpedo Boats the Elco's and the Higgins and the BPBoat design . Though I live in the colony of Oz I have the British Power boat 41 foot 6 inch model at 48 inches , the Vosper Fast patrol boat , the Range Safety Launch , The BPB co Whaleback at 36 inches and the Black Maurader and even the Sea Queen and ALL I/Combustion powered and all over 15 to 20 years young and ALL as well as the Keilcraft 48 inch Cras Boat all all all have this trick and all get up on the plane as the "Brave class" with its Proteus engineer was still a planing Hard Chine hull and as such it is the hull chine strakes that are so essential to the design originated by was it Georga Selman ? and Hubert Scott Payne ?. Oldies are goodies and the masters of old need to be never forgotten for their skills. Regards Lyle and best construction wishes for modifications.
Response by RHBaker on the 23rd Sep 2018
Thanks Lyle, will research your entry. The wider chine strips are an idea had not considered. Will do so, although it works well now that could be a further improvement.
BRAVE BORDERER - Posted: 11th Sep 2018
Been researching the squeal and stutter on other websites and conclude RFI is probably not the major contributor. Others attribute it to a mismatch in the ESC / motor timing, which seems more likely. Whatever caused it, resulted in the affected motor failing. Which came first, the failure causing squeal or squeal causing failure is open to conjecture. Much to my surprise the manufacturer has decided to replace the motor under warranty.
In the meantime, the motors I had planned to use originally (2800kV Outrunners) came into stock, so purchased a couple. Until now have had to use the ESC default settings as did not have a programming card. This also arrived with the motors. Following advice from another contributor reprogrammed the motors with “softer” start and acceleration settings.
Fitted and tried the new motors and settings. On the bench, the
squeal and stutter have almost gone. The motors are also more tractable.
As the brushless motors are now going to be used for high speed operation only, with slow on the centre brushed, thought could simplify the controls by putting the brushless ESCs on one control system using a “Y” lead. However, this introduced inconsistent and erratic motor responses. Reverted to the two previous separate controls, port and starboard.
On the water the performance is fine, as is the reliability. The 2S battery gave almost half an hours operation. The bow lifts nicely with both 2 & 3 S Batteries; plenty of spray. Hopefully resembling a 50 knot vessel! Another adjustment is needed to the transom flaps to try to hold the bow down later as she accelerates.
Feeling now to finally be making progress with this model.
The squeal has not gone, nor has erratic motor operation. The squeal is high pitched screech, rather like treading on a budgie! When it happens, bringing the control back to neutral and advancing it again almost always overcomes it. The erratic operation happens also when starting and is rather like the motors are not getting a signal to react to the control. Again, returning through neutral briefly seems to correct it.
The revised motors and ESCs have increased the weight to 6lbs for the hull including all running gear, excluding batteries and superstructure. Whilst still trying to control weight have concluded this figure is satisfactory as the performance certainly is.
Response by RNinMunich on the 12th Sep 2018
Hi Rowen,
i just wondered how much the brass whips compared with steel, and how much it expands with friction heat if the bearings bushes are a tightish fit!?
Don't think I've come across brass shafts before 😉
Good luck👍 Doug
Response by RHBaker on the 13th Sep 2018
Am sure it can do both of those! So far, have not had a high speed run long enough to really test the brass shafts. I hope to only need to use it for a couple of test runs shortly before will dismantle, make those upgrades and then finish the model over the winter.
Response by jbkiwi on the 22nd Sep 2018
I've used small brass shafts in brass bushed tubes with oilers in my MTB and they've lasted for 20yrs of average use, although they get a bit noisy when short of oil. Best would be brass shafts in brass tubes with Teflon/Nylon/ bronze etc bushes (a center bush as well if poss - have used these in ic power boats for years with hard steel shafts for the power). Brass is good as it's self lubricating to a degree and with a good quality oil can run quite smoothly and quietly, and is very simple, and when looked after won't corrode like steel or miniature ball or roller bearings (unless stainless).
BRAVE BORDERER - Posted: 29th Aug 2018
Decided to separate the two power systems; one to the port ESC and motor and the other the starboard. Hope this will reduce interference between the motor systems. Have also reverted to a remote battery powered Rx rather than the BECC system, again to reduce possible interference. The modifications did not resolve the problems. The squeal and stutter are still present, but much reduced. Sounds rather like a slipping coupling, but as these have been checked many times they can be eliminated. Apart from the squeal and the stutter, everything works well. The squeal /stutter occurs at start up, when it happens the control is returned to neutral, If the motor is immediately reselected, usually the problem goes away and the motor runs up cleanly. It only occurs when both motors are selected at the same time. Either runs up cleanly when selected individually.
Interestingly enough, did some research on various Model Boats site and found some references to RF interference, no specific solutions though. Also examined some Aero modeling sites as they use powerful brushless motors with ESCs. There is some history of the problem there. Evidently when the mosfets (?) of the ESCs convert DC to AC, RF interference is generated. It can often be addressed by using ferrite rings on the ESC control leads. My latest ESCs actually have ferrite rings, so the problem must have been anticipated. This might account for the latest reduction in squeal and stutter levels.
Am at a loss to think of any other modifications, so decided to conduct a water test. Maybe it is a characteristic of brushless motors, but their control response seems “ragged”, not smooth as with a brushed. Anyway, the squeal and stutter seemed reduced yet again, perhaps the water load damped them down.
Was able to start exploring both the performance envelope and the viability of the brushed centre shaft motor. First impressions are that on a 2S battery the performance is fine, but it sparkles on 3S. On 3S the stutter and squeal are more pronounced though. Intend to do further trials but, unless something unexpected occurs, now plan to use 2S power.
The centre brushed motor idea works well, this layout seems a good compromise. Will design a simple switching circuit to ensure the brushless motors can selected separately. This will avoid the inadvertent operation of both brushed and brushless unintentionally as they are on the same control stick. The brushed can then be used for low speed operation.
Returning to the problem of squeal and stutter – has anybody else experienced this and how was it resolved?
Response by jbkiwi on the 24th Sep 2018
Have just posted a video of my 64ft HSL model. I have the same problem, and you will hear if you watch the video, that when it's given some gas, it gets a slight continuous squeal on one motor. Some of it is from the silicone tube couplers I use, slipping on heavy acceleration, but the continuous noise is the motor. I'm guessing this is what you have, and like you I just put up with it, or drive slower.
Response by RHBaker on the 24th Sep 2018
Will be posting a blog update shortly describing my trials and tribulations with brushless motors. By using the "softest" start programmable ESC settings have found the squeal is largely eradicated. If you have not tried them, it is worth the trouble.
The slipping coupling will not help, but am sure that will be corrected. I am using solid universal joints, which although noisy, give a positive drive. Your boat looks to go well, but hard to judge from onboard pictures.
Response by jbkiwi on the 25th Sep 2018
Good to hear you are making progress with the noise. My ESCs are not programmable as far as I know (There may be a card somewhere). They were cheap Chinese waterproof car/Buggy ESCs with Fwd and Rev which I wanted for independent drives but for the price and how well they work, you can't beat them (about NZ $20 each) They have a very soft start (you can count the revs) programmed in as std, and the only problem I have found is that they sometimes won't go straight into reverse without quickly nudging forward and back, (just need to drive in a scale manner and it's fine.) I'll put a pic of the unit and motor in (also a brushed one I am using in the MTB (x2) which work perfectly only NZ $9.00) They have braking, FWD, FWD+REV and batt type adjustable by jumpers. Throttle set-up is simple with full FWD and partial Rev set by the sticks. Both types are 30A and never even get warm.
I purchased some fans for them but have never used them. The brushless units have a fan plug on them. The squealing I have may just require a switching frequency change on the ESC (8kHz/16kHz -more RF noise on 16kHz but more efficient) but I don't think I have that option (do you have that option to try on your set-up ? might be worth a crack). The sound units muffle it a bit anyhow. Boat runs at 10mph (GPS) flat out (looks way off scale) but only needs about 1/4 - 3/4 throttle for normal cruising. Will try to put up an external vid soon. Transmitter is easily modded to twin throttles,- excellent cheap set for boats ( later model has internal aerial)
BRAVE BORDERER - Posted: 19th Aug 2018
Blog 4 update – Adjustable transom flap using metallic tape did not work. Think the vibration caused flexing and fatigue, so it finally split. Fortunately had established the correct angle, so reproduced the flap arrangement with a fixed thin alloy plate. Much more robust.
Have installed the new brushless motors and ESCs. The current layout is brushless motors on the outer propellers and brushed on the centre, all powered by a single 3S Li-Po battery and Rx.
Am hoping to commence water trails this week, but have found an issue which was also present with the original brushless motors.
When either brushless motor is powered up it operates nicely, however, as soon as the second motor is started either motor “stutters” and a pronounced “squeal” can be heard. The brushed motor is unaffected. Have now tried several ESCs but to no avail, the issue remains.
It can be cured though by powering each brushless motor with it's own battery. When this is done everything powers up cleanly and quietly.
The obvious solution is to use two Li-Po batteries and abandon the single battery approach. Am reluctant to do this as the model weight will increase yet again.
Has anybody experienced this when using twin brushless motors and, if so, how was it resolved?
Response by RNinMunich on the 19th Aug 2018
Hi Rowen,
Interesting snag! Can you send me a wiring diagram please.
Sounds like you might be getting some cross coupling of control pulse ripple through the battery wiring.
Reminds me of similar problems on naval COMMS systems where we had to fit filters to all the power supplies to prevent cross coupling of sensitive info from 'Secure' to 'Plain' systems via the power leads!

BTW: All brushless squeal and scream until the the pitch gets beyond human hearing frequency range 😉
Alternative: If you use two 3S LiPos, each of half the capacity of the original, you should get the same endurance with only a small weight penalty. This ain't curing the real problem though 😉
Cheers, Doug 😎
Response by jbkiwi on the 22nd Sep 2018
Starting a bit backwards here as have posted more recently with some ideas. If you are going to have a twin brushless system using 1 REC, you probably should have twin 2200Mah 2s lipos, a power lead (I use a JST plug set) taken from the input leads of ONE ESC (not the batt leads) (I break into them and solder the JST leads on ) run those to a UBEC and then to your REC switch then to your receiver. If your ESCs have a built in BEC, withdraw the red power wires from the BEC receiver plugs and tape them back as you now don't need the power from these. If your TX is 2 stick 4/6ch etc and is capable of being changed to 2 throttle sticks (provision for ratchet strip - copy if necessary - on opposite gimbal - ie using set up as mode 1&2 throttle) you can use the existing throttle and elevator stick to give full independent control with either rudder or aileron Ch for rudder. The Chinese ESCs I use have a power switch as well as BECs which is handy. I would keep the brushed system separate from the brushless altogether with its own battery (or try power from the other batt as described above) otherwise you may be trying to mix 3 phase and single phase at some point. If you are using 2.4 you could use another paired 3ch receiver (does work, as mentioned in my later post) to only run the brushless throttle from a rotary sw on your TX (if you have that )
BRAVE BORDERER - Posted: 23rd Jul 2018
This hobby gives countless opportunities for changing ideas! After some thought, have decided to try another approach.
Whilst brushless motors give fantastic performance; so far have had poor experience of system reliability. As more information and advice from other modelers is gathered, suspect have been using undersized ESCs, accounting for many of the problems.
However, whilst still waiting for the new brushless motors an idea developed. To instal a brushed motor on the centre shaft, whilst retaining brushless on the outers.
My thinking is this could provide several advantages such as; a better slow speed performance more suitable for manoeuvring, lower current draw, improved fuse life and a reliable BECC output. It will also operate at below the Li-Po cut-off voltage, giving a “get home” facility in the event the brushless ESCs cut-offs operate. However, there is a slight weight penalty as brushed motors and ESCs are heavier than brushless.
Fitted a brushed motor of the same O/D and mounting arrangement as the previous brushless to minimize installation issues. With a reliable Mtroniks ESC from my stock and suitable fuses, fitted these items along with the ballast and battery used earlier. Now, back to the pool.
The system worked well. The vessel speed is much less than with a brushless motor on the centre shaft, but control-ability greatly improved. With the triple rudders she steers nicely.
The thought of using a brushed motor on the centre shaft, with a brushless motor on each of the outers is attractive. It is hoped the additional operation of the outers in conjunction with with the centre shaft, will provide the expected performance. The centre shaft would then also provide manoeuvring and reliability with the outers shut down.
If this works, think this power-train combination could be ideal. Once the new brushless motors and ESCs arrive will instal and report.
On the attached pictures, the first shows the ballasted model sitting with the brushed centre shaft motor, the second with a brushless. The difference in draft is imperceptible, the bow sits slightly high in both cases. The third shows the model with the brushed centre shaft operating only at “full” speed.

Attached Photos - Click To View Large
BRAVE BORDERER - Posted: 8th Jul 2018
Whilst waiting for the new motors and ESCs, reviewed videos of the vessel under power and noted that as the speed increases, the bow lifts towards a plane. However, as she gathers speed the transom flaps become effective, forcing the bow down in a cloud of spray. At this point the plane has been lost and the model becomes almost uncontrollable.
Decided to temporarily ballast the hull to simulate the new motors and ESCs, then try to establish the optimum flap angle using just the centre propeller and shaft. This is the original 2838 brushless motor installation with a 30 mm propeller. With this simulated drivetrain it would also be an opportunity to determine the best battery locations for both 2 and 3S Li-Po batteries.
Made up an angle template with a spirit level to get the correct deck inclination with the vessel floating at rest. From this located each type of battery statically - somewhere close to the mid-point of the hull. Which also seemed as good a place to start as any!
Somewhere in the research for this model found a reference to the transom flap angle. This was at a 2 degree -ve (pointing downwards) angle. Installed the 2S battery and tried the model. The bow dug in at speed. Adjusted the flap to a straight and level position and tried again. The bow still wanted to dig in, but to a reduced extent. Readjusted the angle to 2 + ve and repeated. The bow now lifted so the forefoot just cleared the water and then remained in that position.
Replaced the 2S battery with the 3S. The extra power obviously increased speed and the bow lifted slightly further. The spray was deflected by the chine rails and a level plane established.
The conclusion is that the transom flap angle is critical to the correct planing of this model and that it should not be negative.
Until the new motors and ESCs are fitted will leave the transom flap and battery locations as is. Once these components are installed, intend to repeat the test. Am confident that with some fine tuning the model can be now made to plane properly at a scale speed.
Interesting to note that the model will just about plane with only one propeller operating – wonder what it will be like with all three?
Response by RHBaker on the 12th Jul 2018
Thanks. Not too difficult to rig something up like that. Just need some backordered items so can try them!
Response by RNinMunich on the 12th Jul 2018
Bon chance mon ami👍
Don't know what TX you have but you may be able to do the mixing there.
If not there are several separate mixer boards on the market.
This one for instance; Action Electronics P40D from Component Shop.
It's good for both brushed and brushless motors😊 See pdf data sheet.
Mode 1 might be good for Brave Borderer!?

Have fun, cheers, Doug 😎
Response by RHBaker on the 12th Jul 2018
Hi Doug,
Certainly having fun and gaining more appreciation for the various drivetrain combinations available to us. My objective for this summer is to get a combination, using all three shafts, that works properly at all speeds.
This coming winter will refine by using items such as you recommend. That item would help, so will keep the details on one side.
The program would be assisted enormously if a supplier (located in Hong Kong) was able to meet back-order commitments!
H.M.S. BRAVE BORDERER - Posted: 18th Jun 2018
Decided to retry with the 2S battery and the original scale style propellers. Concluded that the speed is fine, especially in the windy conditions encountered and in a small pool that limited acceleration. The model had a very flat plane, must adjust the transom flap angle to see what effect that has. The forefoot did not rise much from the water surface.
Was frustrated by the “stutter” referred to in the last blog, noticed this occurred on the two out shafts only and when the starboard was operated after the port was running. Swopped the starboard motor over with the centre one to see what effect it would have. As started to remove the motor noted that a connector was not tight and that the screw had corroded. Exchanged motors, removed all connectors then cleaned and refitted using a water resistant lubricant. The stutter seemed cured.
Another lesson learnt, when dealing with these high currents every connection is tested and all defects exposed.
The opportunity to retest using a 3S battery arose so installed it, all worked fine on the bank. Put the model in the water and a major short occurred. 2 fuses blew and about 6” of wiring melted and burnt through the insulation. At least there was no hull damage!
Did an inquest and, apart from the damage described, also found the starboard ESC and motor had failed. These were the ones where the “stutter” originated, but cannot see any correlation between the two problems.
Discussed the model with some of fellow scale modelers and concluded that the 4500kV motors are unsuitable for the scale propellers used. Every suggestion points toward motors in the 1 – 2000kV range. As now needed to obtain a new motor and ESC, decided to reequip both outer shafts with 2000kv motors and water cooled ESCs.
Felt modifying these outer shafts would allow assessment of this new drivetrain combination, could then decide what approach to take with the centre shaft. Due to the mounting and driveshaft arrangement, the choice of motors was restricted to 28mm O/D with a 1/8” shaft size. Unfortunately, suitable items are on back-order from Hong Kong, so there will be no further updates for a while.
Response by RNinMunich on the 19th Jun 2018
Hi Rowen, you could always use small cable ties to hold the ESC wires down. The motor wires then look after themselves 😉
Look forward to some pics / vids of the Teakwood in action👍
G'night, Doug 😎
Response by bikerjohn57 on the 19th Jun 2018
If its of any help I run a all wood Perkasa with one motor (came from a old battery power tool) powered with a lead acid 12 volt, so as you can imagine its heavy.

But she will plane as per any photo you can find on the NET. 😊

You state that you are waiting for parts from HK, is your BB a Hooben model ?. I purchased one of these and found the moulding of the transom to be atrocious and the company's customer service to be non existent.
Response by RHBaker on the 19th Jun 2018
Hi. Thanks for your comments.
Before I started the BB did some canvassing of the net to find other builders. The drivetrain remarks were particularly interesting. The consensus seems to be that building three screws, as is scale and as I am determined to do, is the most complex and that for performance it is better using either single or two.
Once deviating from scale bigger propellers also work better. I have rather limited my options with being determined to capture the original layout though.
The vessel is being scratch built on a hull from MTBHulls, of which I am well pleased. The HK source is HobbyKing, often find their products are on backorder, but usually only take a few days to arrive. In this case have been advised it will be rather longer.
H.M.S BRAVE BORDERER - Posted: 1st Jun 2018
Now the spray has settled have assessed these first tests; have also reviewed various pictures and U Tube videos of the Brave and Pekasas in operation. The actual vessels look to plane rather like mine, whilst some model bows lift up until a significant length of keel is exposed.
Anyway, have been able to draw some conclusions:
1) Moved the battery towards the stern and, at speed, the forefoot lifts slightly clear of the water. The plane is now almost flat. The battery is not well positioned when near the bow.
2) The 2S battery used was a 4000mAh 30C; suspect this battery does not have the capacity to operate the model. Every motor will run up smoothly until a second one is operated. The first motor then “stutters” and a fuse might blow, this could be indicative of a power surge. Any comments from the electronic experts among the group would be appreciated.
3) The 3S battery was 10,500mAh and 40C; with this battery all three motors can be run at full speed together and fuses do not blow. It was also very heavy at 1700g, holding the model down.
4) The motors are 4500 kV. On refection, think a slower motor around, perhaps 2000 kV would have been a better choice.
5) Would concur with comments by others that a simple single or two bladed propeller layout for this model is probably best - that is unless you want to capture the true scale layout. The centre propeller seems to have little effect on overall performance, although it will power the model quite nicely when operating by itself. Have had several suggestions about how best to use the centre propeller. Will think about them and decide later how to do this when I start to finish the model.
6) The 2 blade Hi – speed propellers both increased performance and current draw. The model is more than fast enough with the original scale layout.
7) Will purchase a lighter, 3 S battery as that seems the best choice for performance and weight.
8) Testing using the bare hull with a minimum of detail worked well. For a models with a complex power train, this is a good approach as access to the internals can be gained easily. Nothing worse that finishing a boat carefully just to find the performance disappointing. Then having to to rip it apart to make major modifications or adjustments!
Response by RNinMunich on the 1st Jun 2018
Evenin' Rowen,
So far so good, nice job👍
Let me go through your comments one by one😉
1) "Moved the battery towards the stern and, at speed, the forefoot lifts slightly clear of the water. The plane is now almost flat. The battery is not well positioned when near the bow."
Battery in the bow is almost always bad news🤔 too much weight forward of the CoG or natural balance point when planing.
2) "The 2S battery used was a 4000mAh 30C; suspect this battery does not have the capacity to operate the model. Every motor will run up smoothly until a second one is operated. The first motor then “stutters” and a fuse might blow, this could be indicative of a power surge. Any comments from the electronic experts among the group would be appreciated."
First the battery: you may be right. Especially with 3 x4500 kV motors Since you are using 3 ESCs how about feeding each one from a slightly smaller (lower weight) battery? Precondition of course is that all three are equally charged to the same voltage and capacity AND have the same (or very very similar) internal resistance! Complicates the issue of course and motors with a lower kV rating and one power source may well be the better solution😉
Second the 'stutter': How and when did you switch in the second motor?
If the first was still at 'Full Ahead', i.e. 'Pedal to the metal!, I might expect the battery voltage to dip and then recover with the sudden additional load and a sharp rise in total current drawn. But no particular excuse for a sudden current rise in the first motor ! Where was the fuse that blew? I suspect in the primary supply lead from the single battery🤓 since with brushless motors you can't fit individual fuse in their supply leads like you can with a brushed motor. BUT you can to the ESCs feeding them!!! You can't get a power surge from a battery, not like a surge on the mains network due to lightning etc! But you can get a voltage dip and recovery if you suddenly present it with an additional load😲
3) "The 3S battery was 10,500mAh and 40C; with this battery all three motors can be run at full speed together and fuses do not blow. It was also very heavy at 1700g, holding the model down."
All run up together to full speed or 'switched in' as described above?
There's a big difference between a gradual increasing of load on a power source and a sudden step increase!
4) "The motors are 4500 kV. On refection, think a slower motor around, perhaps 2000 kV would have been a better choice."
I did think at the outset that 3 x 4500kV was perhaps a little ambitious😲
2000 - 2500 sounds much better, and more controllable👍 Then you could also get good performance results with a single battery of capacity lower and weight 👍 The function of the third (centre) motor for 'action speed' would also be more pronounced👍
5) "Would concur with comments by others that a simple single or two bladed propeller layout for this model is probably best - that is unless you want to capture the true scale layout. The centre propeller seems to have little effect on overall performance, (see above re 4500kV motors- Doug😉) although it will power the model quite nicely when operating by itself. Have had several suggestions about how best to use the centre propeller. Will think about them and decide later how to do this when I start to finish the model."
As a 'Scale Purist' (as far as my skills and tools allow!) personally I would frown on the use of 2 blade props, much less only a single prop. Do that in a fictitious power boat if you will, but for 'Brave Borderer' ? 😡
Do her justice please😉
Many three screw (😲) boats (including the full size originals of this era) only used the third motor for additional manoeuvring speed in action situations.
My personal experience of FACs (Fast Attack Craft) and FPBs (Fast Patrol Boats) over the last three decades shows me that the three screw configuration has been largely dropped, especially since the introduction of much more powerful engines such as improved diesels and gas turbines. Many use a combination of diesel, for cruising, and gas turbine for 'action speed', so called CODAG, COmbined Diesel And Gas turbine.
6) "The 2 blade Hi – speed propellers both increased performance and current draw. The model is more than fast enough with the original scale layout."
As I believe the 2 blade props were of larger diameter (and perhaps also of larger pitch) than the 3 bladers the higher current draw is a logical conclusion! Stick with the scale config! 👍👍👍
7) "Will purchase a lighter, 3 S battery as that seems the best choice for performance and weight." 👍 but don't overdo it to the other extreme by reducing weight and therefore capacity too much😲 You want a decent sailing time don't you?
8) "Testing using the bare hull with a minimum of detail worked well. For a models with a complex power train, this is a good approach as access to the internals can be gained easily. Nothing worse that finishing a boat carefully just to find the performance disappointing. Then having to to rip it apart to make major modifications or adjustments!"
Heartily agree 👍👍👍
Bon chance mon ami😊
H.M.S BRAVE BORDERER - Posted: 30th May 2018
itted 2 x two bladed 35 mm “hi-speed” propellers to the outer shafts only as these are the easiest to change. Can also use the centre shaft measurements as a check of the previous figures as it is unchanged.
With these propellers the current draw and bollard pull both increased. Subjectively, think she was also slightly faster, but the speed exceeds scale speed anyway.
The increased load on one of the 2 bladed props wiped the blades off and several 30 A fuses on various motor circuits blew.
Originally, the battery was fitted as far forward as possible to hold the bow down – some thing it seems to have achieved! Decided to remove the forward battery location frame and replace it with one which will allow the battery to be positioned anywhere between the bow and the centre of the model. The battery can now be located where the best plane is achieved. Once the correct battery is fitted the final location will be determined. This frame movement will also allow adjustments for any weight gained during final finishing.
Whilst the idea of using a load cell and ammeter/wattmeter to measure bollard pull and motors loads sounds logical, it is fraught with challenges. The vessel both bucks and the readings fluctuate wildly under load making getting steady, consistent results difficult.
Off now to cogitate over the results and decide a path forward.

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H.M.S BRAVE BORDERER - Posted: 24th May 2018
Looks like everything is set for the first open water test. Sun is shining, ice has gone and water smooth.
Intention is to start the open water test program with a repeat of the pool test, except this time with everything wired correctly; the load cell positioned so the “pull” is more horizontal and ballast available to hold the propellers underwater if necessary. Hope these improvements help reading stability.
To modify the “pull” arrangements, wrapped a light cord around the propeller shaft struts and fed the loose end above the transom shelf and out over the stern. The load cell was hooked into this and then tied to a fixed grating on the pond side.
Started by measuring the electrical requirements for each of the three motors and the propeller bollard pull, using the 2 S battery. Found the bollard pull was up slightly at almost 3 lbs per propeller. Probably because they were now held at a greater depth in the water. Also blew several 20A fuses, so fitted 30, which seem to work.
A series of runs showed adequate performance with plenty of spray, although the bow did not lift much onto the plane. The forefoot did raise almost above the water surface.
Then tried a 3S battery. Although this was much heavier, the performance improved dramatically. The bollard pull was up to almost 18 lbs per shaft. The bow still did not lift much to a plane, although the forefoot was almost clear of the water at full speed. The battery was located just back from the bow, so it is suspected that it held the bow down. The impact of the transom flap down angle could also hold the bow down, but have decided to leave as is for the time being and avoid the temptation of making too many adjustment at once.
Whilst it is still too early to draw definite conclusions, it seems as if a 3S battery will be required.
The model sustained some slight damage due to the test arrangements, so will repair that and also fit the 2 bladed Hi Speed propellers. Will then repeat the program and report. Should be able to draw some definite conclusions then on the best power train.
Neither of the batteries used, neither the 2 S nor the 3S are ones I would choose for this model. As a result the capacities and weights are not ideal. That must also be remembered in future deliberations.

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