That version of "Islands_init.c" seems to be ancient. It doesn't have the alternative location for 'rIsland.reload.l2' used by "Woodes Rogers". In any case, you'd need to use 'rIsland.reload.l5' rather than 'rIsland.reload.l2' for your new shore, otherwise you're replacing Devil's Throat and probably throwing the worldmap into confusion because it still thinks Devil's Throat is supposed to be there.
None of which matters if you're trying to add a new shore near Cartagena because you'll want to look at the section for island "Colombia", not the section for "Redmond".
But for another example which is already in the game and which does work, take a look at "Conceicao":
Code:
rIsland.reload.l5.label = "Linda Praia";
rIsland.reload.l5.name = "reload_4";
rIsland.reload.l5.go = "Conceicao_Shore_03";
rIsland.reload.l5.emerge = "see";
rIsland.reload.l5.radius = 200.0;
rIsland.reload.l5.pic = 26;
rIsland.reload.l5.tex = "t2";
rIsland.reload.l5.enable = false;
rIsland.reload.l5.goto_enable = false; // Screwface: Disable Sail-To
That was added by
@Bartolomeu o Portugues for his "Family Story" sidequest. There's no provision for this shore on the worldmap so you'll never see it there, and I don't think it appears on the island map either. So you just have to sail round Grenada and find it the hard way. And the same will probably be true if you add a new shore to Colombia, except you can't sail round the "island", you'll just have to sail along the mainland coast looking for the shore...
Just to complicate matters, adding or changing a sea locator doesn't take effect until you start a new game. This is different from land locators which will be there if you change the locator file and then load a saved game. So after you've added the locator to "RESOURCE\MODELS\Islands\Cartahena\Cartahena_locators.gm" (and done all the necessary work to add the location), you'll need to start a new game, sail near Cartagena and try to find the new shore. If it's not where it's supposed to be, you'll need to change the locator, then start a new game, sail near to Cartagena, etc... This is where using TOOL to write locators to a text file, reading the text file into the island model, and saving the result as a new file, really helps. You can then use GM viewer on that new file to see where your locator is. Once it looks right there, write the locators back to the text file, load "Cartahena_locators.gm", read the text file and save the result.