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Messages - Brian.Dixon

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1
Projects - Glacier Boats of Alaska boat projects / Re: Ed's boat in Perth
« on: December 01, 2021, 12:12:11 PM »

That's OK ... it was a huge undertaking.  Life gets in the way sometimes (mostly always) ...


2
Projects - Glacier Boats of Alaska boat projects / Re: Ed's boat in Perth
« on: November 22, 2021, 09:20:56 AM »
Hi Ed, Long time no see!  If someone else is finishing that boat out, it would be fun to know about it ... maybe see some pix?

bd


3

Those are great close-ups ... very helpful, showing what you can see if you're actually there :D

4
There is a guide that you can buy for Canadian waters that tell you the the direction and flow of the water for each day.  I know you guys are fast but working with the tide will save you a bunch of cash in fuel.
I don't see us traveling to Alaska until 2023.  I will be looking for buddy boats for that year.

Chuck, I got a water woman for you.  Actually 2.  Call me.

Reminds me of the joke ... "Wanted: Wife who owns boat.  Send picture of boat."


5
General Discussion about the Great Alaskan / Re: Getting ready for paint
« on: November 10, 2021, 10:43:37 AM »

The problem with dust is that getting rid of it stirs it up ... you can blow/sweep part of it out, but you'll have to repeat several times.  A fine spray of water on everything in the shop (mist) stabilizes dust, even after drying.  The best solution is to have a shop dust filter running 24/7 while you go in a couple of times a day to blow/sweep dust out again.  You can hang tarps or curtains around the painting area, e.g. isolate the boat zone from the rest of the shop and thereby minimize the area that needs to be dust free ... like a paint booth.

6
Looks good from here ... :D

7
Projects - Glacier Boats of Alaska boat projects / Re: Building a 27'-0 GA
« on: November 04, 2021, 12:54:06 PM »
Thanks Brian for that info, I will work out some numbers and readjust the tanks.
If you don't mind I will post the new placement and see if you approve.
Thanks

It's important to know the motor and bracket weights, and size of bracket as well.


8
Projects - Glacier Boats of Alaska boat projects / Re: Building a 27'-0 GA
« on: November 04, 2021, 07:12:55 AM »
Brian would you please look over these numbers for the fuel tank and the water tank. I want to make sure the balance is correct. the numbers are nominal by a inch or two.
Thanks

OK ... As mentioned in the thread (link) above, I usually tell people to center fuel/water and other "consumable weight" around 60% of the way back from the bow to top of transom.  1) if you do this, then the boat stays reasonably balanced around the CG as the consumables (water, fuel) get used. 2) The 60% rule is a bit on the forward side ... it hedges the bet a bit because most boats 'gain weight in the stern' over time and/or are used with lots of weight in the stern (fish, ice, people, gear loaded in the boat).  The CG in your drawing is close enough, so we'll use it.

What you want to do is calculate the moment-arm (lb-ft) of the various weights around the CG ... a moment-arm is effectively the torque (around the CG) applied by a weight in the boat.  I'll let you do the hard math and figure out where the center of the fuel and water tanks are, but here goes ...

Fuel tank: Center of fuel tank is 2.42 feet behind the CG.  At 6.1 pounds per gallon for gasoline, the full 120-gallon tank weighs 732 lbs.

  Fuel tank moment-arm = 732 lbs x 2.42 ft = 1769 lb-ft (in the direction of bow-up trim)

Water tank: Center of water tank is 3 feet forward of the CG.  At 8.3 pounds per gallon for water, the full 30-gallon tank weighs 249 lbs.

  Water tank moment-arm = 249 lbs x 3 = 747 lb-ft (in the direction of bow-down trim)

In reality, you'd add the weight of the tanks themselves too but this is close enough.  It looks like you need to add weight forward or slide the tanks forward, or add a second fuel tank in front of the original ... consider saddle tanks inside the aft end of the pilot house or low-box tanks beneath accommodations on either side ... or on the flip side, put less weight on the transom than required (no bracket or light/short bracket, direct-inject 2-stroke outboard etc).  Or ... some combination of the above.


9
Projects - Glacier Boats of Alaska boat projects / Re: Building a 27'-0 GA
« on: November 03, 2021, 04:49:33 PM »
Brian would you please look over these numbers for the fuel tank and the water tank. I want to make sure the balance is correct. the numbers are nominal by a inch or two.
Thanks

Sure ... a little later this afternoon after I'm done working. 

bd


10

Don't miss a season of fishing for the boat build ... take an inspirational break and go fishing!


11
Projects - Glacier Boats of Alaska boat projects / Re: 30' GA in Elma Wa.
« on: November 03, 2021, 07:38:13 AM »

Very good looking cuddy ... the downslope and curves are just right!


12

There's no reason for precision on the waterline ... if you like it above the minimums, then that's fine.  It slims down the 'impression' of the side panel height.  Another thing that I like to do with waterlines, is to give them a bit of a 'smile' shape, a little up at the stern versus completely level.  It's an old boat builder's trick that improves how the boat appears to be trimming when in the water ... like, stern-low doesn't look stern-low.


13

IMHO, Meranti/Hydrotech is good for bottom panels and chines due to it's higher density/weight and impact resistance.  Weight down low is good.  Same for all decks other than the sheer decks - Meranti is my choice.  But for all other ply in the boat ... I prefer Okoume for that ... smooth and light, very consistent.  Lighter weight up high is good.

14
Great Alaskan FAQ / Accurate motor size (hp) calculator link
« on: October 29, 2021, 01:17:48 PM »

From Dan Boccia, 29-Oct-2021:

"Had a great season with my boat, love it more every time I use it.

Here is the best engine size calculator I've found online:
https://btb.fishing/boat-horsepower-calculator/

For reference, my boat, built with okoume plywood (lightest available) plus foam core for much of the cabin, with 9.5 ft cabin, 100 gal fuel, anchor winch, 3 people, loaded for shrimping, fishing, with dinghy, safety gear, spare parts/tools, the engines, a fridge, heater, complete electronics and everything else for a multi-day trip in Alaska weighs 6750 or so. Maybe even a bit more, little things add up! So my first recommendation, as soon as you get your trailer, drag it across a scale and get it's exact weight. Then once the boat is on the trailer, drag it across again to get the hull weight, then you can get a spreadsheet started with all the accessories you plan to add to the boat. My boat was built super light, with no overkill on the glass schedule, so the hull and cabin are as light as you can probably get it, and on top of that I camp for days at a time on my boat so it has more accessories than a pure fishing vessel would have.

Pay attention that this calculator uses statute mph, so you have to convert from knots to mph. Brian designed the boat to cruise around 22 knots, so I use 25 mph for the low cruise, and practically speaking, the boat goes up to about 28 knots at reasonable fuel burn for me so I used 32 mph at the high end. The result is 225 hp for low cruise, and 288 hp for high cruise.

My typical rpms are low 4000's to around 4500 rpm when conditions are decent, going around 25-28 knots with my 250AP Suzuki V6 - same block as the 300 hp. There is no way I'd want that to be a 4-cylinder 200 hp engine - it would be wound up pretty high much of the time.

A note on props: I went with a prop that put me a little lower in the recommended rpm range, around 5600-5700 rpm (recommended range 5500-6100) so that I would get more efficiency at cruise...I'm generally very easy on the throttle and could care less about hole shot. That said, when I'm in heavy seas and need to hit the throttle more aggressively to make a move, it's probably a bit hard on the drivetrain, so the sense of security with that larger engine feels reassuring.

So, if your build is going to be light, with minimal equipment, and you don't pack hundreds of pounds of ice....you might be fine with the 200....but don't take anyone's word for it, use the calculator!"

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Boat builders ... especially builders of BIG boats ... have a special kind of resilience ... be proud and look forward to enjoying the fruits of your labor.  You are accomplishing a Big Task that you'll never forget!

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