Author Topic: My Official build thread. 27 1/2’ GA (Read 185751 times)

Tom Freeburg · « **Reply #510 on:** July 04, 2020, 09:13:50 AM »

How do you go about determining the COG? This seems like an important step for placing a big item like a fuel tank.

Djeffrey · « **Reply #511 on:** July 04, 2020, 11:45:11 AM »

I knew that at one time. Basicly it’s at the rear bulkhead or rear door. Maybe Brian will pipe in with an measurement for you

Brian.Dixon · « **Reply #512 on:** July 04, 2020, 12:20:31 PM »

Quote from: Tom Freeburg on July 04, 2020, 09:13:50 AM

How do you go about determining the COG? This seems like an important step for placing a big item like a fuel tank.

The CG is around 9' forward of the transom on a 26' GA. Slightly farther forward on longer GA's or Kodiaks. The thing to keep in mind is that it's not an exact science, and that items have more effect on trim the further they are from the CG. That's why I suggest tanks and batteries, or other heavier items get placed so that they are nearer the aft pilothouse bulkhead. Close 'nuf...

Brian

Todd j · « **Reply #513 on:** July 05, 2020, 11:47:43 AM »

Here’s what I did. The dimensions are still accurate. The volume of the tanks may have shanked slightly. Less volume if anything. But you get the idea.
The COG was figured from a number I got from Brian. I can’t remember how I shifted it to fit my length

Brian.Dixon · « **Reply #514 on:** July 06, 2020, 07:18:32 AM »

Given my remarks above, the rule of thumb is to keep the fuel CG somewhere around the typical location of the aft pilothouse bulkhead. Other thoughts ... the ideal trim of a Great Alaskan at rest is the bow trimming higher than the stern by 1" to 2", definitely not down at the bow, when the boat has half fuel, most of the gear, and no people in it - self-draining when unattended at a dock (you can also add slope to the cockpit deck to help on this topic). You want water to drain aft in other words. The other side of the coin is that boats, like wives, tend to gain weight in the rear over time... fishermen, ice boxes, more gear than planned on etc. You don't want to trim too low at the stern on the first pass either. Before you worry too much about this stuff though ... don't. As I stated above, close is close enough and these boats are big enough to be forgiving of slightly non-optimal layouts (all boats are non-optimal in one way or another!)

Brian

Todd j · « **Reply #515 on:** July 13, 2020, 10:07:09 PM »

I found the info on COG and tank placement with Brian’s recommendations. It’s on page 2 of this forum titled “fuel tank placement “. Sorry guys not smart enough to provide a direct link.

Just trying to stay busy waiting on the last bit of underfloor piping. Glued the aft house bulkhead in and built another home made hatch in the head. This ones for the shower sump. I have been obsessing with all the under deck details. In a couple weeks all of it will be hidden forever! Pics coming before I cover it all up

Todd j · « **Reply #516 on:** July 16, 2020, 12:04:46 PM »

My solution for Power venting the aft End of the fuel coffin. Similar on the forward end. It’s just not photogenic yet😜. Here’s a shot at the other end.

Brian.Dixon · « **Reply #517 on:** July 16, 2020, 02:30:01 PM »

Looks like $$$ stainless! I think I recall you saying that when you mentioned avoiding flexible hoses ... the tubing you've put in looks awesome!

Rbob · « **Reply #518 on:** July 17, 2020, 01:04:57 PM »

Very cool pipes! Nicest looking ventilation I have seen.

Todd j · « **Reply #519 on:** July 18, 2020, 07:03:40 AM »

Put in the house decks for good yesterday eve. Used 90 some pool noodles under the house. I ripped some in half and glued them to the floor as an attempt to maintain a clear drainage path through the limbers. Hope this will allow some circulation of air too. I just kinda put them in there without forcing them otherwise I probably could hav fit several more.