Even when I install the Roll Control I will stay occasionally have tanks on my deck loose. I have a couple of double rigs to deal with. These cannot be taken apart but the good thing is that they do not tend to roll around. I will wedge them up front. Open center console boats are great for diving but they do lack storage space so this is something you will have to deal with. For warm weather areas they are hard to beat for versatility.
I am not sure what your experience level with boats or diving is so just let me say--do not anchor the boat and then leave it unwatched on the surface. If the anchor breaks free your boat may leave without you! Someone needs to remain on board for watch duty. Also, if there is any current run yourself a stern line and make sure it is visibly marked so other boat traffic does not entangle it.
I am not sure what your experience level with boats or diving is so just let me say--do not anchor the boat and then leave it unwatched on the surface. If the anchor breaks free your boat may leave without you! Someone needs to remain on board for watch duty. Also, if there is any current run yourself a stern line and make sure it is visibly marked so other boat traffic does not entangle it.