Height above water.

[Ozzie]

I replaced my rego sticker the other day . Most annoying job. So while at it I scraped off all the other tired and faded capacity and nav ID stickers and after degrunging the cockpit cabin wall replaced them all with nice new shiney stickers fron RMS ( about all you get for free from them so indulge yourselves )

One new one I had was 'Height above water' . It comes with stick on numbers but I had no real idea ....anyone ever measured the mast tip to waterline height? Not that relevant to me as the only place I ever go is near bridges all too low anyway to get under without lowering the mast but there may be unexplored creeks on LM with power lines.

Next time out I'll run a tape measure up the main halyard and then measure from the mast base to the waterline unless someone here has already done so.

[Mark]

Ozzie

Having just started my Master 5 Maritime course at TAFE and just completed the subject on Stability this measurement may be a number of things i.e. waterline to deck or waterline to some other point. Seems we need to understand the requirement for Yachts in addition to stink boats ... I'll ask my mates at Marine Rescue but I think they may also be mystified. I'll also ask my tutor at TAFe and post info here.

Regards

[no way]

Pretty sure that they mean "Air Draft". Trendy name for waterline to highest point on mast . So that means including aerials ,lights, windexs etc.

[Ozzie]

This is the spiel from the RMS govt site

http://www.maritime.nsw.gov.au/sbh/safe ... signs.html

"Overhead power lines

As clearance height can vary according to water levels, it is most important that masters know the heights of their masts and understand the height level given on any sign.


Most of the existing signs on the water give the clearance of the power lines as the clearance above Mean High Water Springs or the average of very high tides. It is important to know that this clearance height may be reduced during king tides or floods.

However a new crossings signage system is progressively being introduced on NSW waterways. The new signage advises the maximum vessel height which can be navigated under an overhead crossing. It is important to note that clearances may be reduced during floods.

To assist boaters Roads and Maritime Services has developed a sticker which you can use to help you remember the height of your vessel above the water line. You are encouraged to place the sticker close to the steering position of your vessel.

Extra caution is required during the changeover period from the old to the new system and when launching/retrieving vessels with a mast on shore. Always keep a lookout for overhead power lines."

[seanslife]

G'Day Ozzie
I know it's an old thread but I'm seeking the answer as I'm drawing up vital statistics for inclusion on a vessel-info plate that I'll get made and stick on the bulkhead. I recently drove from Canberra to Hawkesbury river and enjoyed a week of sailing in my old stomping ground, a few overhead powerlines there nowadays!

Cheers
Sean

[Ozzie]

Sean , would you believe I measured it ages ago and lost the measurement before I ever put in on the sticker. I will be on the boat tomorrow and do it again .

[seanslife]

Ozzie
I just brought the boat home in preparation for a trip to Newcatsle and took the opportunity to measure; The following are the heights involved:
Mast length 7.10m (takes into account 6cm of Masthead light)
Mast step height above water line (in my case top of Antifoul): 1.03m
Height above water = 8.13m

So long as tidal height is below MHWS, an Investigator 563 can fit under bridge/cable with a height of 8.13m

[Ozzie]

Well done Sean , sorry about that...I did mean to help but I pulled Spritz off of the mooring yesterday and we have been so busy today scrubbing and cleaning I forgot to measure the heights , mast and base to waterline etc. but you've obviously nailed it. Congratulations on your info plate, great idea.