Ok, couple of things here...
1) A reed switch will probably work if you can get the boat placed accurately. This may be a result of guides/locator pins/magnets, etc.
2) Consider a microswitch instead, although that might introduce other complications.
All switches are available in changeover, normally-open or normally-closed configurations. A normally-open switch is open-circuit when unactivated and closes when activated, a normally-closed switch is closed-circuit when unactivated and opens when unactivated. A changeover switch has a pair of switches in tandem, offering both functions together.
You want your circuit to be active (i.e. the contacts closed) when there is no magnet present and to open the circuit (turning off the lights) when the magnet becomes proximal. This means you need a normally-closed or changeover reed switch.
The next problem you will have is figuring out the current draw of your lights to make sure the switch can take it. If you're using LEDs (small ones, rather than ultra-brights, etc) then figure on 20mA per LED. Ultrabrights are 50-100mA per LED and high power LEDs are 300mA plus.
If you had ten 'little' LEDs and one ultra-bright you'd need about 300mA of switching capability. This will be listed on the spec for the reed switch.
A quick search on RS reveals:
http://uk.rs-online.com/web/c/?sra=oss&r=t&searchTerm=reed+switch+nc&x=0&y=0&sort-by=P_breakPrice1&sort-order=asc&pn=1This one looks promising:
http://uk.rs-online.com/web/p/reed-switches/3615150/It's 250mA switching capability, which isn't enough for the scenario I mentioned above, but would be good enough for 10-12 little LEDs or 2-5 ultrabrights. Higher current switching looks pretty expensive, but you can use other circuits to switch it with cheap reed switches if necessary.
Have you considered using a channel on the remote for the daughter-ship for the lights instead?
Stuart