Pilot Boat Britannia

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Pilot Boat Britannia

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27 July 2015 at 01:06 #59412
Thomas Saunders 1
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@thomassaunders1
This is a new to me, Pilot Boat Britannia. I have had this boat in the water twice, and apparently that is the only times it has been out of doors.

It runs ok, but is under powered and it is under steered. It has the scale pot metal rudder that comes in the kit and it has the pot metal prop as well. The speed control is an ancient, coil and wiper type and it is powered with a 6 volt, gel cell.

This boat was built in 2000 / 2001.

I have a new, electronic , speed control on it's way, as well as an actual brass, 4 bladed prop. Those two thing should make a more reliable unit.

This winter I want to make a brass skeg and larger rudder. To this end … I have no plans or instructions with this. Is it possible to get a scan of just the rudder and skeg, or can someone that has built one of these tell me how the skeg would have been installed?

Any help would be appreciated.
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27 July 2015 at 01:06 #6197
Thomas Saunders 1
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@thomassaunders1
27 July 2015 at 08:08 #59415
ashley needham
Participant
@ashleyneedham69188
Thomas. Just as a thought, would it not be possible to extend the existing rudder a fraction, or even extend the range of movement . Having more thrust will of course make it more responsive to rudder commands as more water rushes past this item. It may be worth simply fitting the new prop and then seeing what the improvement is.

Ashley
27 July 2015 at 10:56 #59420
Thomas Saunders 1
Participant
@thomassaunders1
Hi Ashley,

I am going to put the new prop on first and you are correct, that should help. Also, I stripped the entire drive line out last evening, and regreased the stuffing box etc. In doing that I had to remove the servo tray and I found a bit of binding in the steering servo rods. I was also able to adjust the arm on the rudder post. All in all I did get a bit more throw and the test will be this morning just after the sun is up and I can get over to the water and try it out.

I am also going to put a tad more ballast near the stern. Some of yesterdays pics show that the boat is not quite at the water line at the stern, so the prop and rudder are not getting the water they should.

I definitely want to replace the pot metal skeg as it has got bent a couple of times and it is only a matter of time before it breaks.

Cheers

Tom
27 July 2015 at 12:32 #59421
Colin Bishop
Moderator
@colinbishop34627
Thomas, see my post about this on the Mayhem website.

Colin
27 July 2015 at 17:25 #59427
Thomas Saunders 1
Participant
@thomassaunders1
Thanks Colin … I just saw that.

Tom
27 July 2015 at 20:41 #59432
Gareth Jones
Participant
@garethjones79649
Thomas,

I built a Mountfleet Osprey some years ago, which I think, uses the same hull as the kit for the pilot boat Britannia. I had the same problems that you have. The original white metal propellor was of very poor quality and I replaced it with a 4 bladed brass propeller of 70 mm diameter. I initially used an MFA 6:1 geared motor, part no. MFA 919D, which had adequate power but the gearbox was very noisy even when packed with grease. I subsequently replaced the motor with a direct drive Graupner Speed 720BB Torque, part no 6372, which is much quieter and also has plenty of power in reserve. In both cases I used a 12 V lead acid gel cell battery.

I initially modified the white metal rudder and skeg as I could not understand how the supplied rudder could be fitted, since the axis of the upper pivot shaft did not line up with the lower bearing. However after modification the turning circle was poor so I made a new brass rudder with a 50% increase in chord but the same basic profile. This works fine and is much more robust than the white metal original.

Here is a picture of the two rudders side by side (almost).

Gareth
27 July 2015 at 21:21 #59433
Thomas Saunders 1
Participant
@thomassaunders1
Gareth, thank you so much … that is exactly what I needed to know.

Cheers

Tom
6 August 2015 at 16:31 #59621
Thomas Saunders 1
Participant
@thomassaunders1
My new prop arrived from the US and it is now installed and ready to try tomorrow.

I went a tad bigger at 75mm or 3". Should not need much above an ideal to move her through the water now. I will build a new rudder like Gareth's over the winter.

Tom

Edited By Thomas Saunders 1 on 06/08/2015 16:32:20

Edited By Thomas Saunders 1 on 06/08/2015 16:32:42
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