We created simple WiFi Bridge using two TP-Link Access Points TL-WA901ND
http://www.tp-link.com/lk/products/deta ... 901ND#spec
The bridge worked good connecting 2 rooms in standard Office building (the distance between the rooms was 10 meters, 2 walls between them). When we moved the bridge to the yacht it began to work very unstable although the distance is closer. Obviously the walls on the yacht are made from the different materials and we need the more powerful APs. The only settings considering WiFi signal of the TP-Link APs was:
270M: -68dBm@10% PER
130M: -68dBm@10% PER
108M: -68dBm@10% PER
54M: -68dBm@10% PER
11M: -85dBm@8% PER
6M: -88dBm@10% PER
1M: -90dBm@8% PER
Now we are looking towards Mikrotik devices to build the other bridge. Will the power of WiFi signal of Mikrotik RB951Ui-2HnD (http://router.lv/product/172/lv/) be more powerful than of the TP-Link devices? Or maybe we need different products with more WiFi power? Exactly which parameters describe the power and capacity of WiFi? Thank you in advance!

your yacht can act as a faraday cage, same as caravans...
putting more power at the transmitter doesn't mean the signal will be better, cleaner.
depending on how big the yacht is, install AP outdoor and indoor and reduce the TX power at minimum, cable the outdoor and indoor and you'll be just fine.

cheers

Which exactly devices do you recommend for this setup?