"Am doing this as the Auto style are "slow-blow" and tube rapid. Have found the Auto ones much better that the tube on brushless motors."
I heartily agree Rowen 👍
Culprit is the surge (or so called In Rush current) which occurs when an electrical load, especially motors and other inductive loads, is first switched on.
This surge current can often be much higher than the operating current when the load, e.g. motor, settles down to smooth running.
(We won't here get into the question of back EMF effects on the installation when an inductive load like a motor is switched on!🙄)
You CAN get Slow Blow glass toob fuses, but (in my experience) generally only for relatively low current, a few amps perhaps. Not a lotta use for a high current ESC/motor combo! 🤔
Trust all is well with you and yours 👍🤞
Looking forward to your next Sea Trials 🤓😀
Cheers, Doug 😎