Tickets for Toppy & Rocket hydrofoil

Hi there,
My partner and I will be travelling to/from Yakushima in mid-December this year and are trying to book hydrofoil tickets before we go. The Japanese toppy & rocket website is great, but obviously is only for those who can read kanji! I've also seen the English translation of the timetable, but I can't find any way to actually *book* online.


If anyone has any experience with either:
1. Do we need bookings at all for low season December?
2. If yes, could we ask our hotel to do this for us?
... your advice would be greatly appreciated!

Thank you so much,
Rina

No english online booking form and by e-mail.

Call to reservation center 予約センター（個人）.
https://www.tykousoku.jp/etc/office.html

https://www.tykousoku.jp/fare_time/kagoshima_yakushima.html
冬ダイヤ（トッピー＆ロケット）　平成26年12月1日〜平成27年2月28日
平成26年 = 2014　月=month 日=date 往復割引運賃 : round discount fare
Ticket purchasing limit until 20 min before of ferry dep time.

[booking condition]
https://www.tykousoku.jp/reserve/
Change 航路を選択する(route select) to
鹿児島[Kagoshima]→屋久島[Yakushima],屋久島→鹿児島 (if round)
and dates and travelers numbers 大人(adult)[2]人.
Then click red button 空席状況を見る・予約する.
Next page will be ship numbers[便名] and conditions[空席] table
○(in blue)：残り10席以上 (over 10 seats)
数字(number)：残り座席数 (left seat numbers under 10)
△：満席(full) or 欠航(operate cancel)

Booking starts 8:30 am just one month before.
So if dep on 12 Dec no sales no info today[11 Nov/JST].

My wife and I took the Toppy in May.
A fun ride, more like a plane with assigned seating, no salt spray in the face while walking the deck.
We bought our tickets the day before. There were empty seats then so I'd guess there should be no problem in December buying them day of travel.
One thing to keep in mind is that it doesn't run if seas are running high so keep a plan b in mind, the slower ferry ,air, or flexible time to wait.
Yakushima was great,we wished we'd have had more time there.