Copy the relevant code pertaining to the battleship unit from Units.artdef and use that on your artdef file.
I find it easier to open both Units.artdef files on Asset Editor and copy from the vanilla one to yours.
//Edit: looks like I had the code readily available lol
Code:
<Element>
<m_Fields>
<m_Values>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text="Naval"/>
<m_RootCollectionName text="UnitFormationTypes"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="Formation"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="UnitCombat"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="UnitCombat"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="UnitFormationTypes"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="EscortFormation"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="Units"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="EmbarkedUnit"/>
</Element>
<Element class="AssetObjects:BoolValue">
<m_bValue>false</m_bValue>
<m_ParamName text="DoNotDisplayCharges"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="UnitCulture"/>
<m_ArtDefPath text="Cultures.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="Culture"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="Era"/>
<m_ArtDefPath text="Eras.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="Era"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="Units"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="ProxyUnit"/>
</Element>
<Element class="AssetObjects:BoolValue">
<m_bValue>false</m_bValue>
<m_ParamName text="PlayDeathOnDestroy"/>
</Element>
<Element class="AssetObjects:IntValue">
<m_nValue>500</m_nValue>
<m_ParamName text="DisplayLevel"/>
</Element>
</m_Values>
</m_Fields>
<m_ChildCollections>
<Element>
<m_CollectionName text="Members"/>
<m_ReplaceMergedCollectionElements>false</m_ReplaceMergedCollectionElements>
<Element>
<m_Fields>
<m_Values>
<Element class="AssetObjects:FloatValue">
<m_fValue>1.000000</m_fValue>
<m_ParamName text="Scale"/>
</Element>
<Element class="AssetObjects:IntValue">
<m_nValue>1</m_nValue>
<m_ParamName text="Count"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text="Battleship"/>
<m_RootCollectionName text="UnitMemberTypes"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text="Units"/>
<m_ParamName text="Type"/>
</Element>
</m_Values>
</m_Fields>
<m_ChildCollections/>
<m_Name text="Members001"/>
<m_AppendMergedParameterCollections>false</m_AppendMergedParameterCollections>
</Element>
</Element>
<Element>
<m_CollectionName text="Audio"/>
<m_ReplaceMergedCollectionElements>false</m_ReplaceMergedCollectionElements>
<Element>
<m_Fields>
<m_Values>
<Element class="AssetObjects:StringValue">
<m_Value text="Battleship"/>
<m_ParamName text="XrefName"/>
</Element>
</m_Values>
</m_Fields>
<m_ChildCollections/>
<m_Name text="BATTLESHIP"/>
<m_AppendMergedParameterCollections>false</m_AppendMergedParameterCollections>
</Element>
</Element>
</m_ChildCollections>
<m_Name text="UNIT_BATTLESHIP"/>
<m_AppendMergedParameterCollections>false</m_AppendMergedParameterCollections>
</Element>
Change UNIT_BATTLESHIP, to whatever your unit name is.
Thanks for the help. That did not seem to fix it however. For some reason it is just using the warrior.
https://www.dropbox.com/s/l660m0koscltry0/Dreadnought.rar?dl=0
Above is my mod. Here is the contents of my artdef:
<?xml version="1.0" encoding="UTF-8" ?>
<AssetObjects::ArtDefSet>
<m_Version>
<major>4</major>
<minor>0</minor>
<build>253</build>
<revision>293</revision>
</m_Version>
<m_TemplateName text="Units"/>
<m_RootCollections>
<Element>
<m_Fields>
<m_Values>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text="Naval"/>
<m_RootCollectionName text="UnitFormationTypes"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="Formation"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="UnitCombat"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="UnitCombat"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="UnitFormationTypes"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="EscortFormation"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="Units"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="EmbarkedUnit"/>
</Element>
<Element class="AssetObjects:BoolValue">
<m_bValue>false</m_bValue>
<m_ParamName text="DoNotDisplayCharges"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="UnitCulture"/>
<m_ArtDefPath text="Cultures.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="Culture"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="Era"/>
<m_ArtDefPath text="Eras.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="Era"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text=""/>
<m_RootCollectionName text="Units"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text=""/>
<m_ParamName text="ProxyUnit"/>
</Element>
<Element class="AssetObjects:BoolValue">
<m_bValue>false</m_bValue>
<m_ParamName text="PlayDeathOnDestroy"/>
</Element>
<Element class="AssetObjects:IntValue">
<m_nValue>500</m_nValue>
<m_ParamName text="DisplayLevel"/>
</Element>
</m_Values>
</m_Fields>
<m_ChildCollections>
<Element>
<m_CollectionName text="Members"/>
<m_ReplaceMergedCollectionElements>false</m_ReplaceMergedCollectionElements>
<Element>
<m_Fields>
<m_Values>
<Element class="AssetObjects:FloatValue">
<m_fValue>1.000000</m_fValue>
<m_ParamName text="Scale"/>
</Element>
<Element class="AssetObjects:IntValue">
<m_nValue>1</m_nValue>
<m_ParamName text="Count"/>
</Element>
<Element class="AssetObjects:ArtDefReferenceValue">
<m_ElementName text="Battleship"/>
<m_RootCollectionName text="UnitMemberTypes"/>
<m_ArtDefPath text="Units.artdef"/>
<m_CollectionIsLocked>true</m_CollectionIsLocked>
<m_TemplateName text="Units"/>
<m_ParamName text="Type"/>
</Element>
</m_Values>
</m_Fields>
<m_ChildCollections/>
<m_Name text="Members001"/>
<m_AppendMergedParameterCollections>false</m_AppendMergedParameterCollections>
</Element>
</Element>
<Element>
<m_CollectionName text="Audio"/>
<m_ReplaceMergedCollectionElements>false</m_ReplaceMergedCollectionElements>
<Element>
<m_Fields>
<m_Values>
<Element class="AssetObjects:StringValue">
<m_Value text="Battleship"/>
<m_ParamName text="XrefName"/>
</Element>
</m_Values>
</m_Fields>
<m_ChildCollections/>
<m_Name text="BATTLESHIP"/>
<m_AppendMergedParameterCollections>false</m_AppendMergedParameterCollections>
</Element>
</Element>
</m_ChildCollections>
<m_Name text="UNIT_ENGLISH_DREADNOUGHT"/>
<m_AppendMergedParameterCollections>false</m_AppendMergedParameterCollections>
</Element>
</m_RootCollections>
</AssetObjects::ArtDefSet>
My mod also has a Mod.Art.xml file which was part of the modbuddy template, not sure if that is needed or necessary?