Some water volume questions

Ok, so I am getting ready to brew up a Pliney the Elder clone, extract version, tomorrow. This will by my 8th brew, with 2 all grains in there as well.

I am trying to get more familiar with my equipment, and dial in volume losses so I can enter more accurate info into beersmith for my profile. I added a sight gauge to my kettle, but am wondering if this was not such a good idea. First off, its an 11" gauge, and after calibration, only has an 8 gallon capacity with my kettle..... and, this is when the sight is filled with cold water. Once its heated up, it begins to spew out of the top. I am thinking that it may be best to just remove it so I am not spewing out wort all through a brew session, especially the longer 90 min boils when I need to add more water to compensate for boil off. Think I should ditch the gauge? I did a test boil today with just water, and I now know exactly ( or very close to) what my boil off volume is.

Ok, my other question: I filled up with 5 gallons of water. I did a 60 minute boil. Drained out ( I should say, I do NOT have a pick up tube) after chilling the water down to about 65, and got 3.5 gallons. What would not drain out I was considering would be my trub loss volume? To figure out my final boil off, I dumped that water into my bucket and came up with 4.25 gallons. Soooo, my boil off comes in at 3/4 gal per hour.

When I brew tomorrow, should I compensate for the 3/4 gallon for trub loss, or is this measurement with plain water not going to be accurate? As I am seeing it now, I have 3/4 gal boil off per hour, and my kettle holds 3/4 gallon below the outlet for my ball valve. I have to do a 90 minute boil for my recipe, so I figure now that I have to add an additional 3/4 gallon for the trub loss ( not sure I should be doing this) and 3/4 gallon for the first 60 minutes of boil and then 3/8 of a gallon for the final 30 minutes of boil. So, I am going to be adding close to 7 gallons into my kettle to start my boil.

Does this sound like a good plan? I am a bit confused on what to do with the water level below the ball valve... I dont want to water down the beer at all, so should I just consider this bit to be lost for good cause? Id rather stay closer to the recipe for quality, rather then add more water for quantity.

Thanks guys

sounds about right.

So you have a larger volume than 8 gallons in your boil kettle? I'm unsure from the first paragraph the size of your kettle.

Yes, account for dead space in your total volume. Overall your plan looks good. For me, BeerSmith's defaults were pretty accurate on boil loss. I make 5.5 gallon batches (into the fermenter) and start with 7.5 gallons for 90 minute boils. I lose about 1/2 gallon per 1/2 hr and a little to trub.

Sorry guys, I reread my post and I can understand how it is confusing.

What I meant by the sight gauge only having an 8 gallon capacity is that the gauge tops off at 8 gallons, when my kettle is a 10 gallon kettle... It sits below the rim of my pot by about 2-3". The problem with it is that it spews out wort when boiling.... Not sure if its worth having on the kettle at this point. I believe I picked up the wrong sized gauge. They had an 11" and a 20". 20 was WAY to long, stuck up 6" from the top of the pot, so I figured that one would be good...

Do you guys just let the gauge bleed out from the top through your boil process?

My kettle is 8 gallons and the sight glass comes to the top of the kettle.

Your best fix is to get a new tube that's longer and just cut it at the top of the kettle. That way you're not gonna boil out of it at all.

Or you could put a fitting like on the bottom and have it just feed back into the kettle, like the Blichmann kettles are set up with the sight glass.