Cllr Marian Berkeley has accused Members of lacking "guts" in their dealings with the Isles of Scilly Steamship Group.
She went on to say she would make sure the issue of last weekend's transport "fiasco" and concerns about the Steamship Group in general were brought up in the House of Lords.
The comments followed the decision at last night's Council meeting to send a letter of support to Cornwall Council over the proposed new air link from Penzance.
After the proposal was agreed, Cllr Berkeley said: "Following the fiasco over last weekend, I find it difficult to sit in a Full Council meeting and not make representations about it. I would like to propose that the Chairman of the Council also writes to the monopoly transport provider bringing the Council's unanimous and strong concern to the attention of its board of directors. I believe a letter from the Chairman of the Council could remove any uncertainty about public reaction to recent developments."
She continued: "There is nothing of course anyone can do to influence the weather but it should be possible in terms of capacity and craft to avoid the sort of terrible situation we had over the weekend. While having enormous sympathy with the crews and frontline staff who have to deal with very frustrated and disappointed travellers - and thanks go to the islanders and staff who provided overnight accommodation and other assistance - it should be recognised that those who could really make a difference are the board of the transport operator by making good decisions.
"Recent decisions have been of enormous concern and have resulted in the Council's total lack of confidence in the management of that company. I just feel that we cannot remain quiet and neutral in this. I do propose that you [Chairman Robert Francis] write to that company on behalf of not only the Council but the community."
When Cllr Jonathan Smith asked for clarification of what a letter would contain, Cllr Berkeley responded: "I would like [Cllr Francis] to ask that any decisions that can affect the performance of transport come to this Council. Capacity and craft used are not adequate at all to serve our economy and community at present and that does need addressing."
However, Senior Manager Craig Dryden cautioned Members to "tread very cautiously" in criticism of any transport provider. "Clearly there's no report in front of us so I think it's very difficult for Members to make any recommendations. In the absence of any formal agenda I would tread very cautiously in terms of any statements being made by the Council as a whole over these matters, which are very sensitive."
Cllr Dan Marcus said: "I don't think it's that complicated really. This is a private company making decisions of a commercial nature. It does affect the whole islands but it is totally within their remit to make the decisions that they make. We are affected by those and I don't think they are as blind to think there is no effect, but to start prescribing how they act is a dangerous road to go down."
Cllr Ted Moulson said he supported Cllr Berkeley and did not consider it a "matter of prescribing".
He added: "I'd just like to point out that we as a Council have been elected by our community to represent our community and I think we as a Council recognise that there have been problems... I think it would be very remiss of us not to take a stand and make our opinions known to the company."
Cllr Smith suggested that a letter should be drafted and then forwarded to the Council's Monitoring Officer for legal advice.
An increasingly frustrated Cllr Berkeley said: "Chairman, I've sat in this chamber for over 30 years and this Council has always lacked the guts to stand up to the transport provider. They have us - I won't use the phrase because it's a bit crude - they have a stranglehold on this community and none of us are brave enough to say it."
Cllr Francis said: "Thank you Cllr Berkeley but we do need to respect the comments of our Senior Manager here. We cannot get into a debate about the particular company involved. I can take a proposal about the letter but I think we should not debate this matter any further at this stage."
Cllr Berkeley then proposed that the draft of a letter go to Monitoring Officer, adding: "I know we're not allowed to name names and this company we all know will remain anonymous... perhaps it'll have to go to the Upper House of Westminster where such niceties don't apply. And I'll make sure it does."
Cllr Steve Sims said a letter was "effectively a waste of a stamp", to which Cllr Berkely replied, "Yes, but at least our consciences will be salved".
Cllr Berkeley's proposal was seconded by Cllr Moulson and the motion carried by a majority of votes. Cllr Avril Mumford asked that her vote against the proposal be recorded.