vertical clearance

[myfalkor]

I just got a 1978 PSC Mariah MKII and the previous owner does not know the vertical clearance required for bridge passages. Can anyone help me before I hit a bridge?

Thanks Mike

[RichH]

Go up the mast with a tape measure (and measure also the antenna, etc. heights) ... the only 'correct' way to do this.

[myfalkor]

Thanks Rich for your reply. I know that is the best way but I am slightly disabled and un able to go aloft. I hoping to find someone to go up but until then was hoping someone knew the vertical height.
As I get into this boat I'm sure I'll have more questions and hope to get some answers.

[kcbillb2]

Another option is, in a word, trigonometry. Seriously, it's just a right triangle problem. With the boat moored to the dock, pick a point on the dock and measure from there to the mast. Then measure the angle from that point to the top of the mast. The only problem would be measuring this angle accurately, but that's most likely not an issue unless you're trying to measure the height to the nearest inch. Then just plug your measurements into the appropriate formula to get mast height.

[wsmurdoch]

I posted the following elsewhere.

I took a 6 ft long 1"x1" stick and duct taped one end of a 100 ft steel tape measure to a spot one foot above its lower end. I tied the two ends of the main halyard together and duct taped the lower 1 ft of the stick to the looped halyard so that the stick extended vertically upwards along the halyard. I raised the assembly to the top of the mast with the stick rising above the mast. My wife stood at a distance on the dock and coached me as I adjusted the top end of the stick to match the top of the highest thing on the mast - the VHF antenna. I placed a board abeam across the boat deck and with the steel tape measured down to the top of the board. I then measured up from the water at the side of the boat to the top of the board. Add it all up and I had the distance from the water surface to the top of the highest thing on the mast.

I got lots of advice from on lookers.

Bill Murdoch
1988 PSC 34
Irish Eyes

[JohnRPollard]

Hi,

Taking a quick look around, most of the listings for Mariahs indicate a bridge clearance of either 45'4" or 48'4". This could be the difference between Mark I and Mark II rigs (although I had thought the difference was in length of the sprit, not height of mast), or just bad info.

Obviously an exact measurement would be good to have, but for your general purposes, you'd probably be safe if you figured 50' with VHF antenna.

[myfalkor]

My thanks to all for the advice. I'm going to try them. Will let you know the out come.
Thanks again,
Mike Bartholomew
1978 31' PSC Mariah MKII

[myfalkor]

Thanks for all the input. I used Bill Murdocks idea using a 6' stick and duct tape. Result: 44'3'' to top antenna
41'3" to top of tricolor light
40'3" to top of mast.
Thanks again for all the input

[pdqaltair]

Originally Posted by myfalkor

Thanks Rich for your reply. I know that is the best way but I am slightly disabled and unable to go aloft. I hoping to find someone to go up but until then was hoping someone knew the vertical height.
As I get into this boat I'm sure I'll have more questions and hope to get some answers.

Then use a long (100') fabric tape and hoist it up a halyard and add some for the antennas and masthead. Then add for the height above the water. Alternatively, hoist a rope and then measure it, adding a few inches for stretch. There is no need to climb for this.

I would NOT take anyone's word, as the rig could have been modified.