They reached the side crater (te manavai) and looked around carefully.	he tuku ki te manavai hee rarama.
Makoi said, 'This is the Manavai of Hau Maka.'	he ki a Makoi.ko te manavai a hau maka
They climbed farther and reached the top.	he iri he oho he tuu ki runga
They saw the dark abyss and the large hole (of the crater Rano Kau).	he ui i te poko uri
They all said, 'Here it is, young men, the dark abyss of Hau Maka.'	he tikea te pakonga he ki anake i ana nei e kau a repa e a te poko uri a hau maka.
They made camp and constructed a house.	he noho o(i)ra he hakatuu i te hare.

Around Rano Kau
Old Land	*Te Pu Mahore*	*Te Poko Uri*
New Land	*Te Manavai*	*Te Kioe Uri*

Judging from its name the side crater should rather be Rano Kao and not Te Manavai:

Kao

1. Side, edge, rim; kao gutu (or just kao), labia minora. 2. Steep, almost perpendicular; thin, skinny. Motu Kaokao, name of one of the islets opposite Orongo, with a steep shape.

Cloth, clothing, garb. (Perhaps a variant of kahu.) Kaokao, side, flank, ribs, lateral. P Pau.: kaokao, the side, flank. Mgv.: kaokao, the side, flank. Mq.: kaokao, id. Ta.: aoáo, id. In Nuclear Polynesia this is particularized, in Samoa to the armpit, in Tonga and Futuna to the sides of the canoe. Therefore it may be considered a borrowing from the Tongafiti.

When Fakataka reached another land she stayed on the upraised reef in the freshwater pools and there delivered her boy child. That was the first station of the new land, a place very close to the sea yet containing sweet water (vai). Accordingly we can guess Te Manavai also to be a place close to the sea and with fresh water:

Manavai

Hollow where rainwater accumulates; anciently, small, round gardens, preferably situated in low shady spots, where the mahute tree was grown.

1. Brain. 2. Valley, ravine, river, torrent, brook; manavai miro, orchard, Mq.: manavai, valley, brook. Ta.: anavai, river, brook. It scarcely appears that these are fully coordinate. In Tahiti anavai has a clear etymology, ana meaning the bed of a stream. In Rapanui and in the Marquesas mana most readily associates with maga, as water in a forked bed.

Maga

Branch (of tree). Magahaiga, part of the arm near the armpit, armpit. Magamaga: 1. Finger (rima matu'a neanea, thumb; tuhi henua, index finger; roaroa tahaga, middle finger; tuhia háûa, ring finger; komaniri-komanara, little finger). 2. Seaweed (shaped like small fingers).

1. (mama 2) A mouthful; maga nuinui, to gobble. 2. Garbage. 3. Index finger. 4. A branch; magamiro, a branch, a limb; magamaga, fork, finger, claw, rod; magamaga miro, a branch, a limb; magamaga rima, finger; magamaga vae, toe; magamaga tumu, great toe; hakamaga, a roof; magaga, fork; magatuhi, index finger; hakamagaturu, slope of a roof.

Confirmation of my suggestion, of Te Manavai being in principle the same place as that where Fakataka stayed after she had crossed the sea, is given by mana → maga = branch, limb, finger. Because the Golden Plover induced her to name the neck, elbow, and knee (i.e. the joints of the limbs) of her baby boy after the name of the Rain Bird:

... When the baby is born a golden plover flies over and alights upon the reef. (Kua fanau lā te pepe kae lele mai te tuli oi tū mai i te papa). And so the woman thus names various parts of the child beginning with the name 'the plover' (tuli): neck (tuliulu), elbow (tulilima), knee (tulivae) ...

Turi

Knuckle; turi-rima, elbow; turi-va'e ankle (also just turi).

1. Knee. P Pau., Mgv., Ta.: turi, id. Mq.: tui, to bend. Turirima, elbow; turituku, to fall on the knee; turituri, dorsal fin G. Turituririma, elbow joint. Turiturivae, knee joint. Turivare, abscess at the knee. Mgv.: turikopia, to walk with knees turned in and legs apart. Ta.: turiopa, weakness of the knees. 2. Pau.: turituri, noise, hubbub. Ta.: turituri, stunned with din. Mq.: tuitui, be still! Ma.: turituri, noise, uproar. 3. Ta.: turi, deaf. Mq.: tui, id. Sa.: tuli, id. Ma.: turi, id. 4. Golden plover (rain bird), Tok.

The Rain Bird (Golden Plover, Tuli) is Sun in his aspect of rain creator, and the joints between the hard limbs are like rain periods, enabling movement because rain works like a lubricant.

The Rain God is first going by canoe across the sea and then he is hovering in midair just like the Golden Plover: