Final answer:
High taxes, the fall of Constantinople to the Ottomans, and high prices due to the monopolization of the spice trade by the Venetians and Genoese were the primary reasons for the search for an all-water route to the East. The term 'the Crades' is likely a typo and not relevant to the situation.
Step-by-step explanation:
The need for an all-water route to the East arose due to a variety of reasons. High taxes imposed by the Ottoman Empire was one principle cause, particularly given they had control over a significant portion of the Silk Roads, leading to valuable goods from East Asia. Hence, the high taxes meant European merchants found it increasingly unprofitable to use the overland route.
Secondly, the fall of Constantinople to the Ottomans in 1453 meant that Europeans had no other choice but to deal with Muslim middlemen in order to access the goods of East and South Asia. This increased the desire to find an all-water, oceanic route to South and East Asia.
High prices also exacerbated the issue, primarily attributed to the monopolization of the spice trade by the Venetians and Genoese, which increased the urgency to find new routes to the East. The least relevant reason is the Crades, which appears to be a typo and thus irrelevant to the situation at hand.
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