Welcome! Nice to meet you!
Well, first I had to Google to find out what sea grapes were!
While learning a bit about about them, I came across this recipe:
"Here is my NanaÃ¢â‚¬â„¢s Sea Grape Recipe given to my mom, then given to me.
2 to 3 quarts of sea grapes
8 cups fruit juice from sea grapes
8 1/2 cups sugar
1/3 cup lime juice
Select ripe and partly ripe sea grapes. Wash and place in large pot, add water to not quite cover the fruit. Bring to a boil and soak until tender. Squeeze juice out by hand or strain through jelly bag, then measure juice.
To each 8 cups of juice obtained, add 8 1/2 cups sugar and 1/3 cup lime juice.
Cook to 225 degrees, which will take about 27 minutes. When it reaches the jelly stage, skim and pour into sterile jars and seal. Makes eight 1/2 pound jars."
(recipe from https://tdaait.wordpress.com/2008/04/19/sea-grape-jelly/)
Can't help you with the wine, though. Perhaps someone else can.