diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
index b6679e83..201fcfc5 100644
--- a/.git-blame-ignore-revs
+++ b/.git-blame-ignore-revs
@@ -1 +1,2 @@
 f728f7fc0e523b6bf33592dd41661cb331efa924
+e5d8bb62af96a0900aa77b348ac076033d38c0fc
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f732802f..51aa57da 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # CHANGELOG
 
+## v0.13.1 - 7 January 2026
+
+- Updates the project capacity check for a true 6 decimal precision check.
+- Breaks apart all long error messages so they are defined outside of the error call.
+
 ## v0.13 - 23 December 2025
 
 ### Default Data Now Available
diff --git a/wombat/__init__.py b/wombat/__init__.py
index 780ae6df..bde190d0 100644
--- a/wombat/__init__.py
+++ b/wombat/__init__.py
@@ -4,4 +4,4 @@
 from wombat.core.library import create_library_structure, load_yaml
 
 
-__version__ = "0.13"
+__version__ = "0.13.1"
diff --git a/wombat/core/data_classes.py b/wombat/core/data_classes.py
index a24800f4..ab7b2e72 100644
--- a/wombat/core/data_classes.py
+++ b/wombat/core/data_classes.py
@@ -372,17 +372,17 @@ def annual_date_range(
     """
     # Check the year bounds
     if end_year < start_year:
-        raise ValueError(
-            f"The end_year ({start_year}) is later than the start_year ({end_year})."
-        )
+        msg = f"The end_year ({start_year}) is later than the start_year ({end_year})."
+        raise ValueError(msg)
 
     # Check the month, date combination bounds
     start = datetime.datetime(2022, start_month, start_day)
     end = datetime.datetime(2022, end_month, end_day)
     if end < start:
-        raise ValueError(
+        msg = (
             f"The starting month/day combination: {start}, is after the ending: {end}."
         )
+        raise ValueError(msg)
 
     # Create a list of arrays of date ranges for each year
     start = datetime.datetime(1, start_month, start_day)
@@ -470,22 +470,25 @@ def check_start_stop_dates(
     if value is None:
         if start_date is None:
             return
-        raise ValueError(
+        msg = (
             "A starting date was provided, but no ending date was provided"
             f" for `{attribute.name}`."
         )
+        raise ValueError(msg)
 
     if start_date is None:
-        raise ValueError(
+        msg = (
             "An ending date was provided, but no starting date was provided"
             f" for `{start_name}`."
         )
+        raise ValueError(msg)
 
     if start_date == value:
-        raise ValueError(
+        msg = (
             f"Starting date (`{start_name}`={start_date} and ending date"
             f" (`{attribute.name}`={value}) cannot be the same date."
         )
+        raise ValueError(msg)
 
 
 def convert_maintenance_list(value: list[dict], self_) -> list[Maintenance]:
@@ -547,10 +550,11 @@ def validate_0_1_inclusive(
         The input value for `speed_reduction_factor`.
     """
     if value < 0 or value > 1:
-        raise ValueError(
+        msg = (
             f"Input for {attribute.name} must be between 0 and 1, inclusive, not:"
             f" {value=}."
         )
+        raise ValueError(msg)
 
 
 def to_datetime(value: str | datetime.datetime) -> datetime.datetime:
@@ -627,10 +631,11 @@ def from_dict(cls, data: dict):
         ]
         undefined = sorted(set(required_inputs) - set(kwargs))
         if undefined:
-            raise AttributeError(
+            msg = (
                 f"The class defintion for {cls.__name__} is missing the following"
                 f" inputs: {undefined}"
             )
+            raise AttributeError(msg)
         return cls(**kwargs)
 
 
@@ -1216,9 +1221,8 @@ def _compare_dates(
             original_start = getattr(self, f"{which}_start")
             original_end = getattr(self, f"{which}_end")
         else:
-            raise ValueError(
-                "`which` must be one of 'reduced_speed' or 'non_operational'."
-            )
+            msg = "`which` must be one of 'reduced_speed' or 'non_operational'."
+            raise ValueError(msg)
 
         if original_start is not None:
             if new_start is not None:
@@ -1284,16 +1288,16 @@ def set_non_operational_dates(
 
         # Check that the input year range is valid
         if not isinstance(start_year, int):
-            raise ValueError(
-                f"Input to `start_year`: {start_year}, must be an integer."
-            )
+            msg = f"Input to `start_year`: {start_year}, must be an integer."
+            raise ValueError(msg)
         if not isinstance(end_year, int):
             raise ValueError(f"Input to `end_year`: {end_year}, must be an integer.")
         if end_year < start_year:
-            raise ValueError(
+            msg = (
                 "`start_year`: {start_year}, must less than or equal to the"
                 f" `end_year`: {end_year}"
             )
+            raise ValueError(msg)
 
         # Create the date range
         dates = annualized_date_range(
@@ -1357,16 +1361,16 @@ def set_reduced_speed_parameters(
 
         # Check that the input year range is valid
         if not isinstance(start_year, int):
-            raise ValueError(
-                f"Input to `start_year`: {start_year}, must be an integer."
-            )
+            msg = f"Input to `start_year`: {start_year}, must be an integer."
+            raise ValueError(msg)
         if not isinstance(end_year, int):
             raise ValueError(f"Input to `end_year`: {end_year}, must be an integer.")
         if end_year < start_year:
-            raise ValueError(
+            msg = (
                 "`start_year`: {start_year}, must less than or equal to the"
                 f" `end_year`: {end_year}"
             )
+            raise ValueError(msg)
 
         # Create the date range
         dates = annualized_date_range(
@@ -1770,16 +1774,18 @@ def _validate_threshold(
         """Ensure a valid threshold is provided for a given ``strategy``."""
         if self.strategy == "downtime":
             if value <= 0 or value >= 1:
-                raise ValueError(
+                msg = (
                     "Downtime-based strategies must have a ``strategy_threshold``",
                     "between 0 and 1, non-inclusive!",
                 )
+                raise ValueError(msg)
         if self.strategy == "requests":
             if value <= 0:
-                raise ValueError(
+                msg = (
                     "Requests-based strategies must have a ``strategy_threshold``",
                     "greater than 0!",
                 )
+                raise ValueError(msg)
 
     def __attrs_post_init__(self) -> None:
         """Post-initialization hook."""
@@ -1865,10 +1871,11 @@ def __attrs_post_init__(self):
                 self, "strategy", clean_string_input(self.data_dict["strategy"])
             )
         if self.strategy not in VALID_STRATEGIES:
-            raise ValueError(
+            msg = (
                 f"ServiceEquipment strategy should be one of {VALID_STRATEGIES};"
                 f" input: {self.strategy}."
             )
+            raise ValueError(msg)
 
     def determine_type(
         self,
diff --git a/wombat/core/environment.py b/wombat/core/environment.py
index f989dcde..bef8102f 100644
--- a/wombat/core/environment.py
+++ b/wombat/core/environment.py
@@ -173,9 +173,8 @@ def __init__(
         if not 0 <= self.workday_end <= 24:
             raise ValueError("workday_end must be a valid 24hr time.")
         if self.workday_end <= self.workday_start:
-            raise ValueError(
-                "Work shifts must end after they start ({self.workday_start}hrs)."
-            )
+            msg = "Work shifts must end after they start ({self.workday_start}hrs)."
+            raise ValueError(msg)
 
         self.port_distance = port_distance
         self.weather = self._weather_setup(weather_file, start_year, end_year)
@@ -491,10 +490,11 @@ def _weather_setup(
         if start_year is None:
             pass
         elif start_year > self.end_year:
-            raise ValueError(
+            msg = (
                 f"'start_year' ({start_year}) occurs after the last available year"
                 f" in the weather data (range: {self.end_year})"
             )
+            raise ValueError(msg)
         else:
             # Filter for the provided, validated starting year and update the attribute
             weather = (
@@ -508,16 +508,18 @@ def _weather_setup(
         if end_year is None:
             pass
         elif start_year is None and end_year < self.start_year:
-            raise ValueError(
+            msg = (
                 f"The provided 'end_year' ({end_year}) is before the start_year"
                 f" ({self.start_year})"
             )
+            raise ValueError(msg)
         elif start_year is not None:
             if end_year < start_year:
-                raise ValueError(
+                msg = (
                     f"The provided 'end_year' ({end_year}) is before the start_year"
                     f" ({start_year})"
                 )
+                raise ValueError(msg)
             else:
                 # Filter for the provided, validated ending year and update
                 weather = weather.filter(pl.col("datetime").dt.year() <= end_year)
@@ -647,9 +649,8 @@ def log_action(
         """
         valid_locations = ("site", "system", "port", "enroute", "na")
         if location not in valid_locations:
-            raise ValueError(
-                f"Event logging `location` must be one of: {valid_locations}"
-            )
+            msg = f"Event logging `location` must be one of: {valid_locations}"
+            raise ValueError(msg)
         total_labor_cost = hourly_labor_cost + salary_labor_cost
         total_cost = total_labor_cost + equipment_cost + materials_cost
         now = self.simulation_time
diff --git a/wombat/core/mixins.py b/wombat/core/mixins.py
index b6a6308a..f3fb2bcb 100644
--- a/wombat/core/mixins.py
+++ b/wombat/core/mixins.py
@@ -81,9 +81,8 @@ def _check_working_hours(self, which: str) -> None:
             start = self.port.settings.workday_start
             end = self.port.settings.workday_end
         else:
-            raise ValueError(
-                "Can only set the workday settings from a 'port' or 'env'."
-            )
+            msg = "Can only set the workday settings from a 'port' or 'env'."
+            raise ValueError(msg)
 
         self.settings._set_environment_shift(
             *check_working_hours(
diff --git a/wombat/core/post_processor.py b/wombat/core/post_processor.py
index 1a5cb1da..8d956c1a 100644
--- a/wombat/core/post_processor.py
+++ b/wombat/core/post_processor.py
@@ -422,9 +422,8 @@ def time_based_availability(self, frequency: str, by: str) -> pd.DataFrame:
 
         by = by.lower().strip()
         if by not in ("windfarm", "turbine", "electrolyzer"):
-            raise ValueError(
-                '`by` must be one of "windfarm", "turbine", or "electrolyzer".'
-            )
+            msg = '`by` must be one of "windfarm", "turbine", or "electrolyzer".'
+            raise ValueError(msg)
 
         by_windfarm = by == "windfarm"
         by_electrolyzer = by == "electrolyzer"
@@ -498,9 +497,8 @@ def production_based_availability(self, frequency: str, by: str) -> pd.DataFrame
 
         by = by.lower().strip()
         if by not in ("windfarm", "turbine", "electrolyzer"):
-            raise ValueError(
-                '`by` must be one of "windfarm", "turbine", or "electrolyzer".'
-            )
+            msg = '`by` must be one of "windfarm", "turbine", or "electrolyzer".'
+            raise ValueError(msg)
 
         by_windfarm = by == "windfarm"
         by_electrolyzer = by == "electrolyzer"
@@ -592,9 +590,8 @@ def capacity_factor(self, which: str, frequency: str, by: str) -> pd.DataFrame:
 
         by = by.lower().strip()
         if by not in ("windfarm", "turbine", "electrolyzer"):
-            raise ValueError(
-                '`by` must be one of "windfarm", "turbine", or "electrolyzer".'
-            )
+            msg = '`by` must be one of "windfarm", "turbine", or "electrolyzer".'
+            raise ValueError(msg)
 
         by_windfarm = by == "windfarm"
         by_electrolyzer = by == "electrolyzer"
@@ -665,9 +662,8 @@ def task_completion_rate(self, which: str, frequency: str) -> float | pd.DataFra
         """
         which = which.lower().strip()
         if which not in ("scheduled", "unscheduled", "both"):
-            raise ValueError(
-                '``which`` must be one of "scheduled", "unscheduled", or "both".'
-            )
+            msg = '``which`` must be one of "scheduled", "unscheduled", or "both".'
+            raise ValueError(msg)
 
         frequency = _check_frequency(frequency, which="all")
 
@@ -972,10 +968,11 @@ def vessel_crew_hours_at_sea(
             raise ValueError("``by_equipment`` must be one of ``True`` or ``False``")
 
         if not isinstance(vessel_crew_assumption, dict):
-            raise ValueError(
+            msg = (
                 "`vessel_crew_assumption` must be a dictionary of vessel name (keys)"
                 " and number of crew (values)"
             )
+            raise ValueError(msg)
 
         # Filter by the at sea indicators and required columns
         at_sea = self.events
@@ -1593,9 +1590,8 @@ def emissions(
         if missing := set(self.service_equipment_names).difference(
             [*emissions_factors]
         ):
-            raise KeyError(
-                f"`emissions_factors` is missing the following keys: {missing}"
-            )
+            msg = f"`emissions_factors` is missing the following keys: {missing}"
+            raise KeyError(msg)
 
         valid_categories = ("transit", "maneuvering", "idle at port", "idle at site")
         emissions_categories = list(
@@ -1606,10 +1602,11 @@ def emissions(
             len(set(valid_categories).difference(emissions_input.keys())) > 0
             or len(set(emissions_input.values())) > 1
         ):
-            raise KeyError(
+            msg = (
                 "Each servicing equipment's emissions factors must have inputs for:"
                 f"{valid_categories}"
             )
+            raise KeyError(msg)
 
         # Create the agent/duration subset
         equipment_usage = (
@@ -1909,9 +1906,8 @@ def project_fixed_costs(self, frequency: str, resolution: str) -> pd.DataFrame:
 
         resolution = resolution.lower().strip()
         if resolution not in ("low", "medium", "high"):
-            raise ValueError(
-                '``resolution`` must be one of "low", "medium", or "high".'
-            )
+            msg = '``resolution`` must be one of "low", "medium", or "high".'
+            raise ValueError(msg)
 
         # Get the appropriate values and convert to the currency base
         keys = self.fixed_costs.resolution[resolution]
diff --git a/wombat/core/repair_management.py b/wombat/core/repair_management.py
index 0ec18129..f8c3b764 100644
--- a/wombat/core/repair_management.py
+++ b/wombat/core/repair_management.py
@@ -525,9 +525,8 @@ def invalidate_system(
             system.servicing_queue = self.env.event()
             self.invalid_systems.append(system.id)
         else:
-            raise RuntimeError(
-                f"{self.env.simulation_time} {system.id} already being serviced"
-            )
+            msg = f"{self.env.simulation_time} {system.id} already being serviced"
+            raise RuntimeError(msg)
         if tow:
             self.systems_in_tow.append(system.id)
             _ = self.systems_waiting_for_tow.pop(
@@ -577,9 +576,8 @@ def interrupt_system(
             system.servicing = self.env.event()
             self.reset_subassembly_processes(system, subassembly_full_reset)
         else:
-            raise RuntimeError(
-                f"{self.env.simulation_time} {system.id} already being serviced"
-            )
+            msg = f"{self.env.simulation_time} {system.id} already being serviced"
+            raise RuntimeError(msg)
 
     def register_repair(self, repair: RepairRequest) -> Generator:
         """Registers the repair as complete with the repair managiner.
@@ -615,10 +613,11 @@ def enable_requests_for_system(
             Set to True if this is for a tow-to-port request.
         """
         if system.servicing.triggered:
-            raise RuntimeError(
+            msg = (
                 f"{self.env.simulation_time} Repairs were already completed"
                 f" at {system.id}"
             )
+            raise RuntimeError(msg)
         _ = self.invalid_systems.pop(self.invalid_systems.index(system.id))
         if tow:
             _ = self.systems_in_tow.pop(self.systems_in_tow.index(system.id))
diff --git a/wombat/core/service_equipment.py b/wombat/core/service_equipment.py
index 80498f49..ddf143b2 100644
--- a/wombat/core/service_equipment.py
+++ b/wombat/core/service_equipment.py
@@ -121,9 +121,8 @@ def validate_end_points(start: str, end: str, *, no_intrasite: bool = False) ->
         ``no_intrasite`` is set to ``True``.
     """
     if start not in ("port", "site", "system"):
-        raise ValueError(
-            "``start`` location must be one of 'port', 'site', or 'system'!"
-        )
+        msg = "``start`` location must be one of 'port', 'site', or 'system'!"
+        raise ValueError(msg)
     if end not in ("port", "site", "system"):
         raise ValueError("``end`` location must be one of 'port', 'site', or 'system'!")
     if no_intrasite and (start == end == "system"):
@@ -823,10 +822,11 @@ def weather_delay(self, hours: int | float, **kwargs) -> Generator[Event, Any, A
             ``hours``.
         """
         if hours < 0:
-            raise ValueError(
+            msg = (
                 f"`hours` must be greater than 0 for {self.name} to process"
                 " a weather delay"
             )
+            raise ValueError(msg)
         if hours == 0:
             return
 
@@ -1334,9 +1334,8 @@ def mooring_connection(
         elif which == "reconnect":
             hours_to_process = self.settings.reconnection_hours
         else:
-            raise ValueError(
-                f"Only `unmoor` and `reconnect` are allowable inputs, not {which}"
-            )
+            msg = f"Only `unmoor` and `reconnect` are allowable inputs, not {which}"
+            raise ValueError(msg)
 
         salary_cost = self.calculate_salary_cost(hours_to_process)
         hourly_cost = self.calculate_hourly_cost(hours_to_process)
diff --git a/wombat/core/simulation_api.py b/wombat/core/simulation_api.py
index 555c9e07..d69c4b45 100644
--- a/wombat/core/simulation_api.py
+++ b/wombat/core/simulation_api.py
@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import math
 import datetime
 from copy import deepcopy
 from typing import TYPE_CHECKING
@@ -269,10 +270,11 @@ def _create_configuration(
         if isinstance(value, Configuration):
             object.__setattr__(self, attribute.name, value)
         else:
-            raise TypeError(
+            msg = (
                 "``config`` must be a dictionary, valid file path to a yaml-enocoded",
                 "dictionary, or ``Configuration`` object!",
             )
+            raise TypeError(msg)
 
     @classmethod
     def from_config(
@@ -313,9 +315,8 @@ def from_config(
         if isinstance(config, dict):
             config = Configuration.from_dict(config)
         if not isinstance(config, Configuration):
-            raise TypeError(
-                "``config`` must be a dictionary or ``Configuration`` object!"
-            )
+            msg = "``config`` must be a dictionary or ``Configuration`` object!"
+            raise TypeError(msg)
         if TYPE_CHECKING:
             assert isinstance(config, Configuration)  # mypy helper
         return cls(  # type: ignore
@@ -431,18 +432,21 @@ def _setup_simulation(self):
             for service_equipment in tugboats:
                 name = service_equipment.name  # type: ignore
                 if name in self.service_equipment:
-                    raise ValueError(
+                    msg = (
                         f"Servicing equipment `{name}` already exists, please use"
                         " unique names for all servicing equipment."
                     )
+                    raise ValueError(msg)
                 self.service_equipment[name] = service_equipment  # type: ignore
 
-        if self.config.project_capacity * 1000 != round(self.windfarm.capacity, 6):
-            raise ValueError(
+        _project_capacity = self.config.project_capacity * 1000
+        if not math.isclose(_project_capacity, self.windfarm.capacity, abs_tol=1e-6):
+            msg = (
                 f"Input `project_capacity`: {self.config.project_capacity:,.6f} MW is"
                 f" not equal to the sum of turbine capacities:"
                 f" {self.windfarm.capacity / 1000:,.6f} MW"
             )
+            raise ValueError(msg)
 
     def run(
         self,
diff --git a/wombat/windfarm/system/system.py b/wombat/windfarm/system/system.py
index d69c88b2..4a84ced3 100644
--- a/wombat/windfarm/system/system.py
+++ b/wombat/windfarm/system/system.py
@@ -160,10 +160,11 @@ def _create_subassemblies(self, subassembly_data: dict) -> None:
             self.subassemblies.append(getattr(self, name))
 
         if self.subassemblies == []:
-            raise ValueError(
+            msg = (
                 "At least one subassembly definition requred for ",
                 f"ID: {self.id}, Name: {self.name}.",
             )
+            raise ValueError(msg)
 
         self.env.log_action(
             agent=self.name,
diff --git a/wombat/windfarm/windfarm.py b/wombat/windfarm/windfarm.py
index b73c93b2..9a64f8b0 100644
--- a/wombat/windfarm/windfarm.py
+++ b/wombat/windfarm/windfarm.py
@@ -233,10 +233,11 @@ def _create_systems(self) -> None:
             name = data["subassembly"]
             node_type = data["type"]
             if name == "":
-                raise ValueError(
+                msg = (
                     "A 'subassembly' file must be specified for all nodes in the"
                     " windfarm layout!"
                 )
+                raise ValueError(msg)
 
             # Read in unique system configuration files only once, and reference
             # the existing dictionary when possible to reduce I/O
@@ -253,9 +254,8 @@ def _create_systems(self) -> None:
                         )
                         raise ValueError(msg)
                     if (subassembly_dict := self._inputs[node_type].get(name)) is None:  # type: ignore
-                        raise KeyError(
-                            f"No configuration provided for {node_type}: {name}"
-                        )
+                        msg = f"No configuration provided for {node_type}: {name}"
+                        raise KeyError(msg)
                 self.configs[node_type][name] = subassembly_dict
 
             # Create the turbine or substation simulation object
@@ -286,10 +286,11 @@ def _create_cables(self) -> None:
 
             # Check that the cable data is provided
             if name == "":
-                raise ValueError(
+                msg = (
                     "An 'upstream_cable' file must be specified for all nodes in the"
                     " windfarm layout!"
                 )
+                raise ValueError(msg)
 
             # Read in unique cable configuration files once to reduce I/O
             if (cable_dict := self.configs["cable"].get(name)) is None: