That, on today's rate of exchange is about GBP 145 a day, but you won't get that 1.61 rate!
Let's say 140 quid a day, 32K pa. Deducting your personal allowance of 10K leaves you with 22K, taxable at 20% = GBP 4400 Income Tax.
Assuming that you are employed and not self employed Class 1 NI on 32K pa is GBP 2885.
If classed as self employed Class 4 at GBP 2163 plus Class 2 at GBP 2-75 per week.
As you are spending over 91 day per year in the UK presumably on leave you are likely to be classed as resident for UK Income Tax purposes. Please come back to me if this is not the case.
From what you say you will not be entitled to Seafarers Allowance. Here is HMRC advice on this complex allowance:
'To get the deduction from your seafarer earnings you must have an ‘eligible period’ of at least 365 days that is made up mainly of days when you were absent from the UK.'
If after this deployment you intend to come back to the UK please advise. Also your last post indicates a change in the daily rate, your original qustion said $235 a day, does make a difference you know!