Your boatReview attribute is null. You need to assign a default value to it as I guess you want to take fresh input and not displaying data from server in edit mode.

<aura:attribute 
        name="boatReview" 
        type="BoatReview__c" 
        access="private" 
        default="{'sobjectType':'BoatReview__c', 'Name':'', 'Comment__c':''}"/>

For a quick check, you can comment the <form> and your page should load without error but form content will not render.

Edit: lightning:input has label and name as required attribute.

<lightning:input 
     aura:id="boatRevw" 
     label="Title"
     name="Title"
     value="{!v.boatReview.Name}"/>

Your boatReview attribute is null. You need to assign a default value to it as I guess you want to take fresh input and not displaying data from server in edit mode.

<aura:attribute 
        name="boatReview" 
        type="BoatReview__c" 
        access="private" 
        default="{'sobjectType':'BoatReview__c', 'Name':'', 'Comment__c':''}"/>

For a quick check, you can comment the <form> and your page should load without error but form content will not render.