Re: BVI chart/nav app
For the peanut gallery:
The Garmin BlueChart for the US is fantastic in the Oregon or similar Garmin handheld chartplotter range (higher resolution/pixel count than the lower end Garmins, but you pay for that, of course.) However the US coverage extends to the BVI, but without the same resolution as in the continental US.
The BlueChart for the Southeast Caribbean fixes that. It provides detail in the Virgins that is comparable to that of the US chip in the continental US. Once again, you pay for that.
The small screen is a challenge after using the larger built-ins or tablets/iPads, but a device like the Oregon that is small, rugged, and waterproof and can be retained in a drink holder at the helm in bad weather has its advantages, like when you are threading a reef during a sudden tropical downpour in 100 yd visibility and can't read the bottom visually. That might be an infrequent occurrence, but it's nice be prepared for it.