Twistcore Moro spear with provenance, collected in 1872!

[Maurice]

Yesterday finally my spear arrived.
It is a 19th century spear, with a 46 cm broad tapered blade, with raised central ridge flanked by shallow chamfered fullers.
I was very surprised unpacking it yesterday, because immediately a beautifull twistcore pattern showed up, which was not to be seen on the images I had seen when I bought it.
The 25 cm brass socket with four fluted rings.
The top of the shaft is carved with a band of swags.
The butt of the shaft consists of a seperate octagonal horn piece, enclosing a wooden pipe, probably to attach some endcap that is missing now??

The total length of the spear is 277 cm.

It was collected by captain William Chimmo of the HMS Nassau on his trip to the Sulu Archipellago circa 1872.

I hope somebody can provide more information about this captain Chimmo and of his trip to the Sulu Archipellago.
Also I hope some of the forummembers have other trophees of him, because there were more pieces sold earlier in an auction of this collection.
Also any idea about the colour of the spearhead? It looks like it could be some sort of bronze forged in it??