I tried several of my boats to see if they had a similar ESC and the one which makes a whine is a Crawler ESC . It must pause between forward and reverse, not the best way to go about things in a boat especially if you are sailing around other vessels or needing to make a quick reversing maneuver.

I replaced the ESC for a Marine and it is quieter not and forward/reverse is smooth with no issues. I do not have the manufacturer but will add that information in another reply.

@Fogwall I'll be talking to Iain owner of Component shop later next week, and I will enquire for you to see if they are continuing making various ESC.

Cheers, Pete

@Rookysailor Hi. They're shown on the website but most of them have been out of stock for well over a year. I enquired a a while ago if they'd be making more. I think the intention was to do so but suspect it hasn't happened.

@Fogwall
Action speed controllers ESC, are still available from Component shop.

Cheers, Pete

Hi the noise from the esc is quite dramatic! I use the tiny esc's from Aliexpress which easily run up to 5 amps although quoted higher. There is a whine but when the s/s is in place you cannot hear it.
The investment in the small esc's is about £2.50 each and they are the only ones I use now, last purchase was for 6 esc's at £13.00. They are cheap and they work and are a bit over an inch square and weigh a few grammes.
Roy

I’m no expert on this but it’s also one of my bugbears. My understanding is that it’s caused by the relatively high operating frequency of modern PWM controllers which make the motor coils act like loudspeakers. I think the effect is exploited in the more sophisticated units (eg. Shark brushless ESCs) to provide audible programming information in the form of bleeps. I also believe it’s more efficient.

Older ESCs operated at lower frequencies: my early experience was with a home built RCM&E ‘Pompey’ unit (70s) and then an ‘Action’ speed controller (90s). These did not whistle. Action controllers were available until quite recently and were advertised as low frequency units. Unfortunately they no longer seem to be made but frustratingly, the later ones had very limited adjustability regarding neutral position and control range making them unusable with my elderly RC gear. 90s era Fleet controllers which I've also used, don’t whistle either. For low speed scale models I don’t think any slight inefficiency matters. It might be worthwhile investigating vintage units from back in the day.

Currently I use modern ESCs. I posted some time ago about a Veron Titan Tug project and a Graupner Condor 2. I also run a Graupner Elke, a similar model to yours. All use Mtroniks ESCs with brushed direct drive motors. They do whistle slightly, but I don’t find it intrusive. None are as loud as your model seems to be (there also appears to be a surprising amount of motor noise together with the ESC whine) indeed the tug is almost silent, even on a calm summer evening on our local lake - its wake is louder.

I’m sure others with vastly more knowledge will be able to offer advice, but I hope my observations help.