Chnaged submersible hull to Syldra-class and can't send on voyage?

[Angelhearth]

On our first airship we changed components one at a time, and continued sending it on voyages, but when I try to exchange a Shark-class hull for a Syldra-class hull, all voyage destinations are greyed out. The ship is rank 49, so there shouldn't be a problem. All parts, including the Shark-class hull, has been repaired. I have 59 Ceruleum tanks in my inventory. I can't figure out what I'm doing wrong here.

[Dustytome]

What build are you doing for the submersibles and what build is it with the part? If you had all shark and just added the Syld part, you just took the range from 70 to 15. Remember that the stats for each tier of submersible parts are jumbled, they are not direct upgrades like the airship parts were.

[Vidu]

The Shark-class Hull will give you a Range +40, the Syldra-class Hull Range -15. By exchanging it you lost 55 Range - depending on the rest of your build, it might very well be that your Range-stat is now so low that your submarine isnt able to reach even the closest sector anymore.

[Espritduo]

What is your range stat? Syldra hull has negative range so too much stacking of parts with bad range will make a sub that can't go anywhere. Also, there is a component capacity limit. At only rank 49 you might be hitting that cap with trying to put a syldra part on.

[Kirika-]

Each sub component (Bow, Stern, Bridge, Hull) has stats that can raise or lower the five Stat values (Surveillance, Retrieval, Speed, Range, Favor) that effect the performance of the sub and has a Component value that when combined with other values from the other part, can't exceed the max value afforded to the sub.
Each grade of component (and the Modified versions of those) have different stats and can raise (+ stats value) or lower (- stats value).
If any of the stats of an assembled sub are less than what is required, such as a low Range directly effecting how far away your sub can travel, limiting the ability to even make it to a Destination, then the performance of the sub will suffer.

For example, if you want to be able to find and visit every known destination and be able to find every known rare item, at the cost of retrieval of a limited amount of items and loosing the ability to find more than one different item in each destination, then a:

• Hull = Mod. Coelacanth
• Stern = Mod. Unkiu
• Bow = Mod. Unkiu
• Bridge = Mod. Syldra

Works out to at Rank 75:

• Surveillance = 215 (current known max required surveillance needed to find everything is 195)
• Retrieval = 85
• Speed = 105
• Range = 128
• Favor = 165

The stat values are a bit lower when using non-Modified components.

If you want the ability to find more items per destination, then build a combo with higher Favor (current known max Favor needed to double item per destination aka 'Double Dipping' is 185)
If you want to retrieve a greater number of items per destination, build a combo with higher Retrieval
And so on.....

The below thread is dedicated to Submersibles and has info on build combo and their effectiveness for certain voyages.
See:
https://forum.square-enix.com/ffxiv/threads/357591

As other have mentioned, the Slydra hull is has the biggest "hit" to Range of any of the other sub Hulls.
However, it does provide the biggest Retrieval buffs than any other hull or other component, which makes it good to combine with other components to offset the range issue to build a sub that has a very high chance to return with a very large amount of items.
A Syldra Hull based build is good for farming Kamacite Ore in bulk.