AN EXPERIMENTAL STUDY ON THE RELATIVE MOTIONS BETWEEN A FLOATING HARBOUR TRANSHIPPER AND A FEEDER VESSEL IN REGULAR WAVES

The Floating Harbour Transhipper (FHT) is a pioneering logistics solution that was designed to meet the growing demands for coastal transhipment in the mining sector as well as commercial port operations. The primary advantage of the FHT system is that it can reduce transhipment delays caused by inclement weather, by reducing relative motions between the FHT and feeder vessel. The feeder is sheltered when inside the FHT well dock when compared to the more exposed location when a feeder is in a traditional side-by-side mooring arrangement. This paper discusses previously published studies into the relative motions of vessels engaged in side-by-side mooring arrangements and also presents details and results from a series of physical scale model experiments. In these experiments, both side-by-side and aft well dock mooring arrangements are investigated. The results provide strong evidence that the FHT well dock concept can significantly reduce the heave, pitch and roll motions of feeder vessels when transhipping in open seas – this being the cornerstone of any successful open water transhipment operation.

INSIGHTS INTO THE FLOW WITHIN THE WELL DOCK OF A MOTHERSHIP DURING FEEDER VESSEL DOCKING MANOEUVRES

An experimental campaign has been undertaken to explore the flow around a feeder vessel as it manoeuvres in and out of the well dock of a mothership. The parent hulls for this study are drawn from the floating harbour transhipper concept created by Sea Transport Corporation. Laser measurement techniques have been employed to analyse the flow field within the well dock while the feeder vessel both enters and departs. For the Master of the feeder vessel to safely perform these manoeuvres, the complex flows resulting from the highly confined nature of the well dock concept need to be understood and potentially mitigated. It is shown that the inclusion of vents in the well dock can significantly influence the flow and that their effectiveness is determined by the size of the vents. This study further progresses the authors’ recent work on the same novel concept where the confined water effect of the well dock and inclusion of vents is quantified for both the seakeeping behaviour and the docking/departure performance. It is concluded that the use of vents is very beneficial when a feeder vessel docks or departs the well dock, however a compromise on the vent size must be reached in order to reduce adverse effects on feeder vessel motions when docked and exposed to a seaway. It is likely that the optimum solution, that covers all operational parameters, only requires the inclusion of relatively small vents.

Retinal vasoproliferative tumour secondary to retinitis pigmentosa sine pigmento

Retinitis pigmentosa can be associated with exudative vasculopathy in rare instances, which can manifest as retinal vasoproliferative tumours. We present the case of a 33-year-old woman previously diagnosed with retinitis pigmentosa sine pigmentosa in both eyes. She was asymptomatic and just came in for a routine follow-up eye examination. Thorough examination of the peripheral retina on the right eye revealed a dome-shaped retinal tumour with a feeder vessel and surrounding exudative changes at the superotemporal periphery, consistent with a secondary retinal vasoproliferative tumour from retinitis pigmentosa. She subsequently underwent focal laser photocoagulation of the tumour which resulted in tumour stabilisation. While exudative vasculopathy is very uncommon in retinitis pigmentosa, ophthalmologists need to be aware of its occurrence in such patients. Vision loss may occur from exudation, haemorrhage, retinal detachment and neovascularisation. A thorough examination of the peripheral retina is warranted in these cases.

Pseudoaneurysm of uterine artery complicating caesarean section: a rare cause of intractable secondary postpartum haemorrhage managed with uterine artery embolisation

A 27-year-old woman presented 6 weeks after an uncomplicated lower segment caesarean section with excessive bleeding per vagina. On examination, she had mild pallor with a pulse rate of 86 beats per minute and blood pressure of 116/80 mm Hg, uterus well involuted with closed cervical os and bleeding demonstrated through the cervix. A transvaginal ultrasonography with colour Doppler revealed a normal size uterus with an empty cavity and a hypoechoic area with blood flow within it in the left side of the uterus with a prominent arterial feeder vessel. A CT angiogram confirmed the diagnosis of a 1.3×0.7 cm pseudoaneurysm of the uterine artery near the left cornua of the uterus. After failed attempts to control the bleeding with antifibrinolytics, bilateral uterine arteries were embolised using gel foam. Post procedure, bleeding resolved immediately. A follow-up transvaginal ultrasound after a year revealed no evidence of the pseudoaneurysm and her fertility was preserved.

Hemangiopericytoma of meningo-fronto-naso-orbito-maxillary complex

Hemangiopericytoma (HPC) is a rare vascular tumour and difficult to diagnose clinically. Incidence is reported in fourth to fifth decade of life.With female predominance, 3%–5% cases affect the oral cavity, sinus lining and meninges. The patient presented with 8×6 cm swelling on her face, evaluation reported it to be HPC. Bilateral maxillary artery embolisation, wide local excision of the lesion, preserving the left eye and its function, was done. No recurrence is reported at 1-year follow-up. Response of such lesions to radiotherapy is questionable; with no lymphadenopathy and adequate encapsulation, embolisation of feeder vessel followed by a wide local excision of the lesion seems to be a fairly good option of treatment.

Recurrent pyogenic granuloma caused by intraosseous vessel: A case report

Pyogenic granuloma is a benign localized lesion of the skin and mucosa closely related to trauma, chronic irritation and hormonal changes. The method of treatment is surgical excision. But relapses can occur. For this reason, treatment with alternative methods such as cryotherapy, electrocautery and laser has been investigated in recent years. In this case, the cause of PG was a feeder vessel. The lesion was excised before and recurred within two weeks. An intraosseous feeder vessel was identified by a magnetic resonance imaging. This vessel was exposed and cauterized with electrocautery.

Insight into the Flow Within the Well Dock of a Mothership During Feeder Vessel Docking Manoeuvres

An experimental campaign has been undertaken to explore the flow around a feeder vessel as it manoeuvres in and out of the well dock of a mothership. The parent hulls for this study are drawn from the floating harbour transhipper concept created by Sea Transport Corporation. Laser measurement techniques have been employed to analyse the flow field within the well dock while the feeder vessel both enters and departs. For the Master of the feeder vessel to safely perform these manoeuvres, the complex flows resulting from the highly confined nature of the well dock concept need to be understood and potentially mitigated. It is shown that the inclusion of vents in the well dock can significantly influence the flow and that their effectiveness is determined by the size of the vents. This study further progresses the authors’ recent work on the same novel concept where the confined water effect of the well dock and inclusion of vents is quantified for both the seakeeping behaviour and the docking/departure performance. It is concluded that the use of vents is very beneficial when a feeder vessel docks or departs the well dock, however a compromise on the vent size must be reached in order to reduce adverse effects on feeder vessel motions when docked and exposed to a seaway. It is likely that the optimum solution, that covers all operational parameters, only requires the inclusion of relatively small vents.