Those little boats are great for kids though the 2 in 1 esc/receiver units are terrible. They don't have a low voltage cut off so you end up accidentally destroying the batteries. The included USB chargers are just as bad.

You can fit a 10amp brushless esc and add 2 280 brushed motors along with a rudder and they sail perfectly. They are cute little boats and very popular for hobbygrade conversions

That's quite a collection of batteries. I'll show you my collection sometime.

As for me I believe I got rid of all my Nicads a while back. Even the NiMh batteries seem to be dying off. Right now I'm moving many of my batteries operated vehicles and boats to lithium ion. This seems to be much safer than the lithium polymer.
Lew

Try to keep life simple - even building finicky and complex models. The Polaron charger has been serving me for roughly ten years, charging anything up (or down) to my camera and motorbike batteries. The Lipos in the Firesafe (clad in firebricks - safety first!) are up to 8 years old and all in (near-) perfect condition. The last pic shows 2 useful gadgets: a VERY noisy voltage monitor you can even hear when flying gliders and a de-charger which lowers Lipo-voltage automatically to storage state (storage voltage is IMPORTANT). Good when you have not emptied the battery; happens more often when running boats than flying planes . . . Both by the way cost so little I have a number of them. And I would never buy anything that has to do with electricity IN China. Yes I know, the stuff all comes from China, just like my Lenovo laptop. Differentiate! And when I fry things like ESCs I don't frown at the battery - I squint at the mirror. As I say: keep it simple and safe, don't change a winning horse. Your wallet and your nerves both say thank you.
Ian

As a dyed-in-the-wool Nicad guy, then Nimh, the move to Lipos has been a chore, especially for high speed applications. I think I'll need a phd to figure them out, charging, storage, discharge rates. Yikes! But, dove in with both feet so the quest continues.
😉😂👍

I recommend anyone using or planning on using Lipo (lithium polymer) batteries to check out the differences between them and Li-ion (lithium ion) batteries. There is a noticeable difference between the two, looking at safety and performance.
I knew someone in the model boats hobby whose house burned down because of the LiPO batteries. This is a confirmed fact that thing batteries caused the fire while being charged.
Lew

Hi Jumpugly, you're right to continue your research.

I first came across lithium batteries about 20 years ago.
I first used lithium-ion [Li-ion] batteries and then lithium-polymer [LiPo] batteries, but never for model ships.
I've never considered using lithium batteries in model ships, because I've never had the need.
In addition to professional uses, I've used lithium batteries for professional and commercial drones (especially LiPo ones). For drones, the choice is obvious; currently, LiPo batteries offer the best performance for their lightness.
Even though they've made great progress and safety has improved, I'm very wary. There are still real dangers if you make mistakes during charging, connections (possible short circuits), and storage, but this applies to all lithium types, some more than others.
The same incorrect procedure performed on another type of battery (short circuit, impact, temperature, etc., etc.) or a manufacturing defect on another type of battery, such as lead-acid batteries, will not cause the same consequences as lithium batteries.
This does not mean that in some applications, they remain the best, if not the only, choice.
Deep knowledge is the best weapon, Jump.