From Bangkok Post

The operator of the electric boat service on the Chao Phraya River will add two new routes to and from Sathon pier on Dec 20, and charge a flat 20 baht rate until the end of this month.

Deputy Transport Minister Atirat Ratanasate on Tuesday said the service, MINE Smart Ferry operated by E Smart Transport Co, will feature a “Metro line” between Sathon pier and Rama VII pier and a “City line” running from Sathon pier to Pinklao pier.

The Metro Line will have 12 trips on weekdays from 6.05am-5.45pm and 18 on weekends from 7.30am-6.45pm. The City Line will have 36 trips per day, from 7am-6.05pm.

Mr Atirat said three electric boats will serve each route. 

Next month, the fare on the Metro line will be increased from 20 baht to 25 baht; the City line will remain at 20 baht.

Currently, the EV service is available from Sathon pier in Bangkok to Phra Nangklao Bridge pier in Nonthaburi. The route is the “Urban line”.

https://www.bangkokpost.com/thailand/general/2228091/sathon-pier-gets-extra-electric-boat-routes

I tried the electric boat from near Hua Lamphong earlier in 2020. 

The staff outnumbered customers about 3 to one.  It proceeded at about 6mph, checked with my phone and thankfully was free.  I hope the river boat is much faster.  Experience of a friend's Jag shows electric vehicles can be very fast.

Not sure about these new boats until I have tried one. But I think the older long boat services are much more interesting. So much to see at the side of the river and lots of photo ops for visitors.

From Richard Barrow Twitter site

The new MINE Smart Ferry started operating on the Chao Phraya River on 1st December. The electric catamarans run between Sathorn Pier and Phra Nang Klao Pier. They run every day but on weekdays only during rush hour periods. There is a special promotion price of 20 Baht.

The 24-meter long electric catamarans can be charged in about 20 minutes. The charge will last about 2-4 hours or travel approximately 80-100 kilometers.

 

 

So I assume it simply replaces the old Chao Praya ´Express´ boats that served this route since at least some 25-30 yrs with now very old ageing boats. The ´normal´ service of this has many more stops and takes nearly 90 mins fro whole trip.

Fare has of course also gone up, but remains quite low. New ´attraction´ must be the new giant Thai Parliament buildings about halfway-near the Kiak Kai intersection.

z909: this one runs on the big river, what you mention were the tiny boats along the canal-mostly also serving various ministries. But as HLPong is-or will be- closed soon, it makes even less sense now-if it even still exist