Science with Brendan Thirlmere

The weather here in Bangor has returned to its more familiar state with the recent bout of moderation no more than a distant memory. The rain has returned, and with it, the leak that drips through the deck above the fore-cabin of my boat and making a sodden mess of the fabric on my new foam seat cover.

Drip-drip-drip it went, all day yesterday. Every ten seconds, a drip landing on the foam.

So I decided to make a repair using some sealant and an old baked bean tin (a little trick I picked up in Bangalore)

The rain came again this morning and so did the drip. Not so frequent this time and I decided to time the leak using the stop-watch function on my mobile phone. One minute thirty three seconds! An improvement!

The rain continued to fall and it seemed to be getting heavier. I timed another drip and noticed the heavier rain had reduced the time of this drip to one minute thirty one seconds.

I kept on with the stop-watch test and came up with the following figures:

Drip 1 one minute twenty nine seconds.

Drip 2 one minute twenty six seconds

Drip 3 one minute twenty one seconds

Drip 4 one minute nineteen seconds

Drip 5 one minute seventeen seconds

Drip 6 one minute fifteen seconds

Drip 7 one minute thirteen seconds

Drip 8 one minute thirteen seconds

Drip 9 one minute thirteen seconds

Drip 10 one minute thirteen seconds

The leak had “saturated” at one minute thirteen seconds with the rainfall seemingly constant. I measured the area of the deck I thought to be the rainfall capture zone and made an estimation of the gradient of the deck above the fore-cabin. I then telephoned the Holyhead meteorology office and was informed the ash content delivered by the Icelandic volcano (Esspro!!lig*%thingy) was imparting a four micron particular component to a standard sixty second, one millilitre drip. So I was in luck! My drip had stabilised at one minute thirteen seconds and it was easy to extrapolate the Holyhead data to my own findings. I realised the rate of change was key to my study and set about identifying all the variables that were involved. The data was entered into an Excel file and a curve subsequently generated. I then set about developing a model for the dynamic progression and produced the following formula:

òP-(K/wt) + Ö4y

Where P = estimated rainfall density

K = Deck absorption

T = Drip time

The model worked beautifully and I was able to forecast the rainwater collection at the seat fabric target point to 98% accuracy.

I then sent the findings to the Bangor Hydro-Marine Technology Institute and have since received their detailed report, which follows:

Bangor Hydro-Marine Technology report.

You’ve got a leak, mate!

David is at a bit of a loose end just at the mo.