As you state, these are known as ship or tulip motifs. They are worked in satin stitch, and in the case of your pattern there is a square eyelet at the ends.
These are worked one side at a time, from base to tip.
I am afraid I can't see the pattern clearly in your photo to be able to tell you the length of the stitches, but you should be able to work that out on closer study.
As with kloster blocks there should be as much thread on the back as on the front. Don't try to skimp on thread by bringing the needle back up beside the hole you went down in, but carry it across the back of the motif each time.
Normally the thinnest section is made from tiny satin stitches over one or two threads, but again I cannot see that clearly. It may be that your pattern is using a cable stitch leading to the square eyelets. The eyelets are normally pulled so that a hole appears in the center of each.
The shape of ships and tulips can vary so it is important to count carefully.
Oh and they are worked with the thicker of your two pearl cottons.
I hope these tips help a little, Patricia.
I will add ship motifs to my to-do list and add a lesson on how to work them in full, to the site.