An independent ship surveyor raised concern about the Francie operating on the Kaipara bar three months before the ill-fated boat sank in the area, claiming the lives of eight people.

Documents obtained by the Weekend Herald throw new light on the months leading up to November's fishing tragedy - one of the nation's worst maritime disasters.

An executive summary completed by an independent, professional shipping surveyor on August 17 last year, cited concerns about where the 12m charter vessel was permitted to operate - even though it "met all applicable Maritime and Marine Protection Rules."

Specifically, the independent surveyor documented concern over the Francie being allowed to operate over the Kaipara bar - the area where the boat would capsize and sink three months later in treacherous conditions.

The surveyor also documented the need for ongoing maintenance and various repairs to the boat - which were discussed with owner and skipper Bill McNatty, one of the eight who perished - as well as worries over unsecured items potentially "flying around the cabin", which had been addressed.

"I was concerned that the operational limits of this vessel allow it to operate over the Kaipara bar and that there was a reasonably large number of unsecured items and equipment including tools et cetera stowed in the forward cabin and engine room," the surveyor wrote, whose identity has been withheld.

"The owner has subsequently removed as much of this as possible to avoid the possibility of bow down trim providing handling difficulties while crossing the bar and the opportunity for loose equipment to be flying around the cabin and forward cabin in the event of any unplanned severe manoeuvre."

"Generally this steel vessel appeared in satisfactory structural condition however sandblasting and repairs are required to many small areas of the hull, bulwark and deck areas and these were discussed with the owner."

The new information is part of 193-pages of reports on the Francie and communications between skipper McNatty and Maritime New Zealand, released under the Official Information Act.

Maritime NZ refused to release a number of other documents, declaring "some of the information you have requested is integral to the investigations and inquiries into the circumstances surrounding the capsize of the vessel."

In response to Herald inquiries, Maritime NZ said "operational limits" refer to specific geographical areas, defining where a vessel is allowed to go.

In this case, Francie had the required certification to operate on the Kaipara bar, but with four conditions imposed by the surveyor - one of which included "vessel to be operated over West Coast bars in favourable conditions only."

When asked whether certification requirements on boats are adequately tough or need to be raised, a Maritime NZ spokesman said the organisation was unable to comment, due to the issue being part of the Transport Accident Investigation Commission's [TAIC] ongoing investigation.

"We can't comment on that, that's one of the things that TAIC is looking at," the spokesman said. "In this case the role of TAIC is to look at whether changes to regulations are required."

Coastguard has previously confirmed it was called to give non-urgent assistance to the Francie - towing it back into the harbour - a month before it sank.

The Maritime NZ spokesman said the surveyor's concerns over the bar were "partly" satisfied by equipment being properly stowed and rejected the executive summary warned of a serious incident.

"No, the surveyor did not. The surveyor noted in his report the changes required were made to avoid Francie going bow down and to not have loose equipment flying around, then issued the certificate of survey with conditions about when to cross the bar," he said.

Other documents released include a vessel manual for Francie, with a page dedicated to bar crossing safety. The manual cites "extreme caution must be exercised when crossing bars" and "if in doubt - don't cross."

A report of compliance check from December 2013 also details a deficiency in "operation and emergency procedures" which were to be rectified within one month.

Tony Walles has operated Kaipara Harbour fishing charters for 20 years and was at the harbour on the day of the Francie incident.

Walles said he is not surprised to hear about the independent surveyors' concerns. Walles said in his opinion, the Francie wasn't powerful enough to operate on the bar.

"No, not at all," Walles said. "The Francie didn't really have the performance, the horsepower, whatever you'd like to label that, to actually be a suitable vessel for crossing the bar."