using craft.request.getParam to filter by relations I'm requesting entries through a search field like so:

{% set params = {
  section:      'tours',
  startloc:     craft.request.getParam('zoekplaats')
} %}


{% for entry in craft.entries(params) %}
...etc..
{% endfor %}


which works fine. However, as soon as the 'startloc' field type becomes an 'entry' (thus a relation) I can't simply state 'startloc:' anymore, as it has become an entire object. However, I'm quite limited to the syntax I can use within that params field. 

I've tried many things but can't really figure it out. Anyone that knows what the correct way to do it would be?

Thanks a lot!!
Wow, ok so I spent all day on this, I seem to have gotten it to work, but to be honest, I'm not 100% sure why/how this works. Anyways, I altered the code in the answer given here: Searching a specific section by four different types of parameters?

And ended with this:

{% set zoekschip = craft.request.getParam('zoekschip') %}

 {% set params = {
section:        'tours',
limit:      null
} %}
                   {% set relatedParams = ['and'] %}


{# plaats #}
{% if craft.request.getParam('zoekplaats') %}
{% set plaats = craft.request.getParam('zoekplaats') %}
{% set params = params|merge({'startloc':plaats}) %}
{% endif %}


{# Schip #}
{% if craft.request.getParam('zoekschip') %}
{% set zoekschip = craft.entries.section('ships').shipName(craft.request.getParam('shipName')).first %}
{% set relatedParams = relatedParams|merge([{ targetElement:zoekschip }]) %}
{% endif %}

                        {# add relatedParams to params #}
{% if relatedParams|length &gt; 1 %}
{% set params = params|merge({'relatedTo':relatedParams}) %}
{% endif %}

{# perform search #}
{% set searchParams = craft.request.getParam('q') %}
{% set entries = craft.entries(params).search(searchParams|trim) %}




                            {% for entry in entries %}
..output..

{% endfor %}


Now, this works, it's pretty awesome, and after examining I understand it, and have a better understanding of how the

  relatedTo: {targetElement:  } 


works :)

My next challenge, is to add another search param, regarding the dates.
The tours section currently has a matrix field which has one block, called 'vertrekdatum'. (departuredate) How I add the date to the param, and check whether any tour has that date in their blocks, and output if so..?

Thanks heaps in advanced!