private double MassTL(ConfigNode cfg = null)
        {
            if (techLevel != -1)
            {
                TechLevel oldTL = new TechLevel(), newTL = new TechLevel();
                if (!oldTL.Load(cfg == null ? config : cfg, techNodes, engineType, origTechLevel))
                    return 1.0;
                if (!newTL.Load(cfg == null ? config : cfg, techNodes, engineType, techLevel))
                    return 1.0;

                return newTL.Mass(oldTL, engineType.Contains("S"));
            }
            return 1.0;
        }