Yeah. You get a huge kelp ball wrapped around a wing keel and the prop wont even move the boat. Not to mention it's near impossible to control even if there's enough wind to sail her in.
Of course it’s a problem. But you don’t let it get so bad that it disables the boat. Any sailor worth his/her salt knows how to clear kelp.
If she didn’t she had no business sailing around the world. There’s plenty of kelp in those big bad oceans!