Günter Bäbler's "Guide to the Crew of Titanic" has more information about this than I've seen anywhere else. It's on Google Play and Amazon for a reasonable price, and it's also on Scribd. Bäbler asserts that job titles in the 1st/2nd class galley corresponded to positions in a traditional French kitchen brigade (
brigade de cuisine). The modern form of that system was invented by Auguste Escoffier, whose "Guide to Modern Cookery" includes most dishes served in 1st Class on Titanic.
"Last Dinner on the Titanic" by Rick Archbold and Dana McCauley is also a good source for this topic; it concentrates on food and probably would have more information relevant to you than even Bäbler's book. It includes recipes for the entire first class dinner on 14 April. A newer book, Veronica Hinke’s “The Last Night on the Titanic: Unsinkable Drinking, Dining, and Style”, might be interesting too. It has modernized recipes for some of the dishes, as well as cocktails that might’ve been served. And it mentions this:
“On the other side, one of the men on the overturned collapsible, Titanic entrée cook Isaac Hiram Maynard (also known as John), recognized Joughin and held out his freezing hand to him. The two men clasped hands in the middle of the ocean. He wasn’t on top with the other men, but he was secured by Maynard’s grasp.”
"Entrée cook" corresponded to "
entremetier." The meaning is slightly different than it'd seem. An entremetier prepares hot appetizers, egg dishes and starches. He is also responsible for soups and vegetables, and he may have skilled subordinates to help with that. Essentially, he turns meats into complete dishes, and more. On Titanic, the meats were prepared by two grill cooks, a roast cook and assistant, and the sauce cook (who is third-in-command after the chef and sous chef). An entremetier is sometimes called a "garnish cook," because everything served alongside meats in French cooking is a garnish.
Also according to Bäbler, the entrée cook had three assistants and was in charge of the vegetable cook and his four assistants. Entrée cook was an important position -- in fact, his monthly wages were £7 10s (£7.50), which was
more than the sauce cook (at £7). The assistant cooks earned £4 10s and the vegetable cook was paid £6 10s. The chef got £20 and the sous-chef £10. Chief Baker Joughin earned £12, so the entremetier had the fourth-highest wages in the whole galley. There are a lot of figures there, but they should help to show how the quite rigid hierarchy worked. I'll add that the à la carte restaurant staff were better paid, and White Star even hid their wages in some records so that 'regular' galley staff wouldn't feel slighted; the restaurant's entrée cook, Auguste Coutin, earned £12 a month. (Like all the other restaurant kitchen staff, he perished.)
So, as you can see, Isaac Maynard, your ancestor, had a very important position in the galley. Unfortunately, any further information is difficult to find. His quarters were probably in the room marked "12 1st cl. Cooks" on
E Deck. His uniform would've been much the same as you'd see today, as can be seen in this
1920s footage from Olympic (about 6:00). His work hours would've been dictated, of course, by Titanic's meal times. In 1st class, breakfast was 8-10 AM, lunch was at 1 PM and dinner was at 7 PM. Breakfast in 2nd class was 8 AM too, but the other meals were 30 to 60 minutes earlier. So, though I don't have anything to support it, Maynard must have worked at least 12 hours a day, perhaps with a break after lunch -- but he wouldn't have had to work at night. That time would've been spent mostly in the main galley room -- if you look at all the stock pots on the
deck plans, you can imagine what his day would have been like, as that's where they cooked soups, starches and vegetables (which were, again, delegated to the vegetable cook/légumier).
This has been long (though hopefully it's accurate), but I thought you'd find it interesting because of the personal connection. I'll finish with something I've said before. When chefs today try to recreate one of the first class meals on Titanic, it takes weeks of preparation and enormous effort, despite their experience and their access to modern kitchens. On Titanic, the main galley staff prepared three meals a day for hundreds of people -- 500 to 600 on the maiden voyage, depending on how many were in the à la carte restaurant, and up to almost 1,450 at capacity. They used steam, coal and primitive electrical appliances. And they did it at sea, in all weather. That really makes me respect the work they did and the effort they put into it.