I like to bury the rails sometimes too. It looks cool and feels cool. However as Nice N Easy says all boats are different.
As the boat heels over the angle of the rudder to the water
changes dramatically. Most boats will go to weather
when overpowered so you add opposite rudder which, because of the heel, starts to become bottom rudder. At some point you run out of rudder and the boat rounds up.
To go faster in this case you have to sail flatter or you have to balance the sails
Rudder is bad because it adds drag. On the race
boat when beating we try to get the rudder centered and in powerful conditions we steer with the main sail traveller.
First we shape the sails
for the conditions. In strong conditions this means flattening the sails. Then we set the jib
and it pretty much stay fixed. The main comes on hard and in gusts we play the traveller to maintain course. Very little rudder input. We work the traveller continuously.
As conditions strengthen more the traveller can reach its maximum down travel. Then you are left with no choice but to main sheet out or the boat will round up.
When we are fully powered the helmsmen actually cannot steer the boat down as there is not enough rudder authority. When we have to duck a boat the mainsheeter actually has to sheet out aggressively and momentarily to let the bow come down.
To improve your boat in strong conditions, not knowing what controls your have on board, I would suggest you try the folowing:
1 - Main sail halyard
as tight as you can get it.
2 - Main outhaul
3 - If you have a traveller, main sheet hard and vang hard. Trim with traveller and be prepared to loose the mainsheet in gusty conditions
4 - If you have an adjustable backstay the backstay should probably be coming on strong.
5 - If you have a main cunningham it should be on hard as well.
All these things will flatten the mainsail
and take power out of it. The boat only can go so fast without planing so excess power from the wind
needs to be gotten rid of.
The idea is to take the power of the wind and transfer it to the water via the sails, boat and keel. The other way I mentioned is to sail flatter.
This entails getting a fat crewperson or 2 to hike out. Take a look at race
boats and notice all the people on the rail. When the boat is flatter the keel is more effective at transfering the power of thboat to the water. There is also less side slip meaning you are going more towards your destination
and finally you are not "spilling" as much air out of the heeled over sails.
Flatter is generally faster in strong conditions.