Tweaks.java

            // Tweak base player speed 
            CtClass ctMovementScheme = classPool.getCtClass("com.wurmonline.server.creatures.MovementScheme");
            ctMovementScheme.getMethod("getSpeedModifier", "()F").insertAfter("if ($_>0 && this.creature.isPlayer()) {" +
                    "   $_ = $_ * 1.1;" +
                    "};");

            CtClass ctCreature = classPool.getCtClass("com.wurmonline.server.creatures.Creature");
            
            // Change max weight
            // 10500 is the multiplier - base is 7000
            ctCreature.getMethod("getCarryingCapacityLeft", "()I").setBody("{ " +
                    "   try {" +
                    "       return (int)this.skills.getSkill(102).getKnowledge(0.0) * 10500 - this.carriedWeight;" +
                    "   } catch (com.wurmonline.server.skills.NoSuchSkillException nss) {" +
                    "       logger.log(java.util.logging.Level.WARNING, \"No strength skill for \" + this, (java.lang.Throwable)nss);" +
                    "       return 0;" +
                    "   }" +
                    "}");

            ctCreature.getMethod("canCarry", "(I)Z").setBody("{ return getCarryingCapacityLeft() > $1; }");
            ctCreature.getMethod("getCarryCapacityFor", "(I)I").setBody("{ return (int) getCarryingCapacityLeft() / $1; }");
            
            // Adjust encumbered thresholds
            ctCreature.getMethod("setMoveLimits", "()V").insertAfter(
                    "this.cantmove = this.cantmove * 1.5;" +
                            "this.encumbered = this.cantmove * 0.9;" +
                            "this.moveslow = this.cantmove * 0.75;"
            );

// ======== VEHICLE TWEAKS

            // Parameters:
            // * ID of Creature or Item template
            // * Base speed (not sure what unit)
            // * Min height of dirt under vehicle that can be traversed (max depth for carts/mounts)
            // * Max height of dirt under vehicle that can be traversed (clearance for boats)
            // * Max slope
            // * Wind impact (boats only)

            ModVehicleBehaviours.addCreatureVehicle(64, new VehicleOverride(40f, -1.5f, 2500.0f, 0.06f)); //horse
            ModVehicleBehaviours.addCreatureVehicle(83, new VehicleOverride(45f, -1.5f, 2500.0f, 0.06f)); //hellhorse
            ModVehicleBehaviours.addItemVehicle(539, new VehicleOverride(1.2f, -1.5f, 2500.0f, 0.06f)); // cart
            ModVehicleBehaviours.addItemVehicle(850, new VehicleOverride(1.2f, -1.5f, 2500.0f, 0.06f)); // wagon
            ModVehicleBehaviours.addItemVehicle(490, new VehicleOverride(8f, -2500.0f, -0.5f, 2000.0f, (byte) 10)); // rowboat
            ModVehicleBehaviours.addItemVehicle(491, new VehicleOverride(5f, -2500.0f, -0.5f, 2000.0f, (byte) 30)); // sailboat
            ModVehicleBehaviours.addItemVehicle(540, new VehicleOverride(5f, -2500.0f, -0.5f, 2000.0f, (byte) 40)); // cog
            ModVehicleBehaviours.addItemVehicle(541, new VehicleOverride(5f, -2500.0f, -0.5f, 2000.0f, (byte) 40)); // corbita
            ModVehicleBehaviours.addItemVehicle(542, new VehicleOverride(8f, -2500.0f, -0.5f, 2000.0f, (byte) 30)); // knarr
            ModVehicleBehaviours.addItemVehicle(543, new VehicleOverride(5f, -2500.0f, -0.5f, 2000.0f, (byte) 40)); // caravel

VehicleOverride.java

package com.wurmonline.server.behaviours;

import com.wurmonline.server.creatures.Creature;
import com.wurmonline.server.items.Item;
import net.bdew.wurm.server.ServerMod;
import org.gotti.wurmunlimited.modsupport.vehicles.ModVehicleBehaviour;

public class VehicleOverride extends ModVehicleBehaviour {
    public float maxSpeed;
    public float maxDepth;
    public float maxHeight;
    public float maxHeightDiff;
    public byte windImpact;

    static boolean DEBUG = false;

    public VehicleOverride(float maxSpeed, float maxDepth, float maxHeight, float maxHeightDiff, byte windImpact) {
        this.maxSpeed = maxSpeed;
        this.maxDepth = maxDepth;
        this.maxHeight = maxHeight;
        this.maxHeightDiff = maxHeightDiff;
        this.windImpact = windImpact;
    }

    public VehicleOverride(float maxSpeed, float maxDepth, float maxHeight, float maxHeightDiff) {
        this(maxSpeed, maxDepth, maxHeight, maxHeightDiff, (byte) 0);
    }

    @Override
    public void setSettingsForVehicle(Creature creature, Vehicle vehicle) {
        if (DEBUG) {
            ServerMod.logInfo("Applying mount mod for: " + creature.getName());
            ServerMod.logInfo("maxSpeed: " + vehicle.getMaxSpeed() + " -> " + maxSpeed);
            ServerMod.logInfo("maxDepth: " + vehicle.getMaxDepth() + " -> " + maxDepth);
            ServerMod.logInfo("maxHeight: " + vehicle.getMaxHeight() + " -> " + maxHeight);
            ServerMod.logInfo("maxHeightDiff: " + vehicle.getMaxHeightDiff() + " -> " + maxHeightDiff);
            ServerMod.logInfo("windImpact: " + vehicle.getWindImpact() + " -> " + windImpact);
        }
        vehicle.setMaxSpeed(maxSpeed);
        vehicle.setMaxDepth(maxDepth);
        vehicle.setMaxHeight(maxHeight);
        vehicle.setMaxHeightDiff(maxHeightDiff);
    }

    @Override
    public void setSettingsForVehicle(Item item, Vehicle vehicle) {
        if (DEBUG) {
            ServerMod.logInfo("Applying vehicle mod for: " + item.getName());
            ServerMod.logInfo("maxSpeed: " + vehicle.getMaxSpeed() + " -> " + maxSpeed);
            ServerMod.logInfo("maxDepth: " + vehicle.getMaxDepth() + " -> " + maxDepth);
            ServerMod.logInfo("maxHeight: " + vehicle.getMaxHeight() + " -> " + maxHeight);
            ServerMod.logInfo("maxHeightDiff: " + vehicle.getMaxHeightDiff() + " -> " + maxHeightDiff);
            ServerMod.logInfo("windImpact: " + vehicle.getWindImpact() + " -> " + windImpact);
        }
        vehicle.setMaxSpeed(maxSpeed);
        vehicle.setMaxDepth(maxDepth);
        vehicle.setMaxHeight(maxHeight);
        vehicle.setMaxHeightDiff(maxHeightDiff);
        vehicle.setWindImpact(windImpact);
        vehicle.setMaxAllowedLoadDistance(10);
    }
}