Okay, it was a fairly good sail last Sunday and certainly the new motive batteries have significantly increased the duration to well over three hours with no loss of speed so that problem has been solved. Other than weed and catching a plastic bag which typically wrapped itself round both inboard props disabling the hip, and blew both motor 5 amp fuses it was a very good sail indeed. The engines are virtually silent and all appears to be well.
The new smoke generator worked well for 2.5 hours pretty nearly continuous smoking then the inevitable happened and the smoke turned blacker and smelt of burning plastic. I had a small fire on board which burned out a hole a good 1" in diameter on the smoke generator and damaged the smoke trunking. No actual damage to the model itself. I just switched off the smoke generator and blew down the funnel which put the fire out.
So why did it catch fire? I figure that after 20 mins it was all at ambient temperature but after 2.5 hours the fog fluid level had dropped quite a bit (it was not empty) but sufficient for the wick absorption rate to decrease to the extent the unused heat caused the element to glow red which in turn melted the top and dropped a small piece of plastic onto the hot element starting the fire. Even a very small flame produces a lot of heat. It would appear that the alloy heat shield I used was just a little short. Repairs consisted of lining the plastic box with thin alloy and extending the heat shield all the way at the top and end with just a hole to exit the smoke into the funnel trunking.
What was pleasing was the smoke was pretty even from both funnels. As a further modification I have stacked two PC fans rather than one. This will not increase the air volume but should increase the ambient pressure a little and it costs nothing to do so lets see what happens next time. Memo to self, refill the smoke generator after 90 mins maximum use. This has not happened before because in my other units the fog fluid capacity exceeds the amp hour capacity of the battery so I would only get about 45 mins. despite the small fire I'm fairly relaxed about this as I believe I know both the problem and the solution.
I have been making oars and small bits for the anchor chain apparatus so just need to get these fitted.
Iron Duke fits readily in my Vectra but the top mast has about 2mm clearance! I'll shorten the top mast just a little for safety - I hope scale purists will forgive me but it also means I can now fix permanent signal halyards from the spars.
Attached are a few pictures.
Next steps is to focus on the turret turning and gunfire system now that I have the key motive elements of the design worked out.
Cheers
Geoff