I used to have a Dahon Jetstream EX on my boat. 20" wheels, full suspension, very light, great to ride. Nearly perfect boat bike except just one thing -- doesn't fold up very small, and fold is awkward. Storage space is a terrible problem even on big boats (mine is 54 feet) so I eventually took it off.

I have loved my Riese & Müller Multicharger on land, which has made car ownership or even carsharing nearly irrelevant living in various European cities. Obviously this is far too large and heavy for a boat. Electric drive is a revelation.

I have been thinking about Bromptons which have the most ingenious fold, sacrificing riding quality with no suspension, few gears, and small wheels, but storage is the key quality for this use case.

I had not considered any kind of electric bike because of all the weight it adds. Then a lightbulb went off in my head -- Brompton Electric has its battery in a bag which you just pull off. With the battery off, it's only a kilo or so heavier than the normal Bromptons. If I can lug it on and off the boat, sometimes using the dinghy, in separate packages, the weight is much less of a problem. Bingo.

So now this is my Plan A. Which model to choose? There are:

1. C-Line Electric, can be had with the H6 gearing, all steel and £1000 cheaper than the P-Line.
2. P-Line Electric which has titanium frame elements and some better components. £1000 more expensive.

Neither has disk brakes, which I've come to really love on the R&M.

So maybe buy a used C-Line, and kill two birds with one stone -- buy the titanium rear triangle and forks with disk brake lugs you can get on Ali Express, and convert to disk brakes?

Anyone have any views/thoughts/experience on this?