Some did, some did'nt, just as some Europeans did and some did'nt, Bantu is more an umbrella term for a greatly varied people who share a general common ancestry than an acual single group.
Well yes. But I'm not arguing for a general survey of Bantu or Swahili seamanship. I'm just trying to get some assessment of the 'peak seagoing' capacity.
Actually, their are quite a few, aside from the Comoros their are the Seychelles as well as the Mozambique Channel islands.
The Comoros aren't actually that much closer to Africa than Madagascar is, and are actually due north. It's not really more feasible to Island Hop from the Comoros to Madagascar. The Seychelles are due north of Madgascar, even further from Africa, and had no history of Swahili colonization - solely Austronesian.
There aren't that many Mozambique channel islands and they don't actually contribute all that much in terms of way stations.
This is not racist, but I am seriously wondering about the Bantu ability or willingness to travel 250 to 500 miles over open ocean to discover Madagascar, or their ability to return with news, and ability to outfit colonizing expeditions.
AFAIK the mainland Africans did'nt have any contact with the Austronesian groups until they went to Madagascar, so they'd have their own ability, most likely expanded upon by the introduction of Arab designs and expertise.
Do you have any references or foundations for that? I would have assumed that any significant seagoing capacity would have been acquired from the Austronesians or the later Arabs. What's the evidence for any significant Swahili seagoing capacity or deep sea capacity that precedes possible Austronesian contact?
They did IOTL; the majority of the Malagasy are roughly 50% Austronesian, 35% African and 15% Other (Arab and Indian mostly) in terms of descent.
Well yes and no. But the OTL African colonization followed rather than preceded Austronesian colonization. I think its much more likely that the Austronesians discovered the African mainland and precipitated exchange and contact.
Arab traders ventured as far as Sumatra, so they would have had some experitise.
Well, except that Sumatra was well known among Austronesian sailing traditions, and Arab traders were basically following the Austronesians back. Sumatra was separated from the mainland by a strait of less than a hundred miles.
So the deep water/exploring capacity isn't necessarily a given.
I can't be sure, but I think Whaling is something that has traditionally only been practiced by peoples bordering the Northern Atlantic and Pacific.
I don't think that there was any Indian Ocean whaling tradition either. I'm also skeptical about any indigenous deep sea fishing tradition.
Overall, I think that based on the information we have, I think that there's an arguable possibility that failure of the Austronesians might well have resulted in Madagascar being largely undiscovered and mostly uninhabited until at least the 12 to 16th centuries.
Their would probably be some trading posts and a few small towns established, with one probably turning into a major trade destination point, possibly taking Zanzibar's place at some point, but yes, otherwise I agree their likely would not be much colonization by the Arabs.
On an uninhabited Island, who do you trade with? All I could really see of value coming out of Madgascar would be feathers and some freakish animals.