I need glue that would be the same with epoxy but less toxic for boat
building in low temperature range?

Epoxy isn't specifically the chemical. Epoxy by definition is just
'two parts'. Now what those parts are, depends on what type of epoxy
it is.

You aren't going to find anything with the strength of epoxy, that is
not epoxy. There are no strong 'one part' glues. All the strong stuff
is two part 'epoxy'. JB Weld, etc.

Polyester Epoxy is pretty bad. Get the expensive stuff, not the
polyester cheap stuff that they use for cars. It's some of the least
toxic, strongest, and most tolerant you will find.

I disagree with the comment above. There are a huge number of high
tech adhesives on the market. You need to decide the exact
characteristics that you want. Epoxy is not necessarily toxic. When
cured it is highly stable and non toxic. In the resin form it can be
an aquatic toxin. It is often the catalyst, part B that is tht toxic
component. Try an altarnative curing agent. We need more info to
assist further.

check out www.mtechltd.co.uk for specific materials help.