Thursday, 19 February 2009

On a roll!

Exciting day at the lifeboat station today! We've been waiting ages for our new rollers and spindles to arrive . . well they finally have!

There are 42 in total, enough to replace all the badly worn steel ones that are in the slipway at the moment.

Allan from RNLI Shoreworks came to station and we installed 7 new rollers into the slipway in the boathouse. The new rollers are made of nylon and with the new spindles are hopefully going to be maintenance free as they require no greasing (good news for me!). Its important that the rollers are the correct height to allow the boat to rock a little bit but not too high so it rocks over to one side and stays there. We did this with an engineers square from the main part of the keelway.

Its also important that the rollers are level so that the boat isn't forced to side of the keelway. This is done with a small spirit level which gives good enough results.

So that's 7 down 35 to go! The steel rollers weigh about 4o kilos each so that's about 1.5 tons of steel to move :o( we as a station have been asked to fit the next 20 the rest will be fitted by contractors as there's some repair work to be done on the plates that support the rollers. Once that's done they'll all be levelled with a laser (some how!) and measurements taken so I can keep an eye on them and make sure they're not wearing.
I'm looking forward to the first launch, the boat should fly down on her new free spinning rollers.


Mart said...

That looks like a lot of hard work!! - The sort of job where you lose all feeling in your fingers til you manage to drop something heavy on one!!

How long is your slip? And whats the difference in terms of how far the boat goes on the slip at low tide and high tide. I know John once mentioned that at the lowest low tides the foot of the slip is almost exposed.

Anonymous said...

Hi Mart

Sorry for the slow reply. You're right it will be quite a lot of hard work, worthwhile though. I am used to having to take the current rollers out once a year, clean & grease them and put them back in. At least this year I can replace them with something a bit lighter!

I don't know the exact dimensions of the slip off the top of my head. In terms of vertical rise and fall we don't really ever get anything over 2 metres. If our slip is 1 in 12 does that mean that there's 24 metres of slip extra showing or is there more maths that that involved?!

At dead low water there's normally about a boat's length of slipway in the water, then there's about a 1 metre drop off the end.

Anonymous said...

Hi again

Whilst having a morning cuppa I found some old drawings for the slipway. I took a few measurements and got the following.

B/House slip = 40'
Main slip = 180'
Concrete toe = 70'

Forgive the imperial measurements but it was a drawing dated March 1975!


Mart said...

Thanks ever so much for the replies Dave. Whats the B/house slip?