TrueGrit/CC Walkaround

Questions about modifying a design

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Bill Edmundson
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Re: TrueGrit/CC Walkaround

Postby Bill Edmundson » Sat Oct 21, 2017 3:50 pm

Joe

I really don't think the exact engine placement is critical on a boat this size. I would take the long section drawing and place the engine as best a could to match that. I don't have TG drawings. Are the frames numbered from bow to stern, or stern to bow?

Both Ray M and Curt G have outboards hanging on the transom, with no problem.

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Re: TrueGrit/CC Walkaround

Postby JoeM » Sat Oct 21, 2017 5:32 pm

Bill Edmundson wrote:Joe

I really don't think the exact engine placement is critical on a boat this size. I would take the long section drawing and place the engine as best a could to match that. I don't have TG drawings. Are the frames numbered from bow to stern, or stern to bow?

Both Ray M and Curt G have outboards hanging on the transom, with no problem.

Bill



The frames are numbered from stern to bow. I heard that Hankinson tended to number them that way but I could be wrong.

I'm not too concerned about the engine CG taken by itself with this size boat, but coupled with a few other modifications I plan on making it adds up quick. Still confident I can overcome that in final design.

Back to the 3D build.
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Re: TrueGrit/CC Walkaround

Postby JoeM » Tue Oct 24, 2017 8:13 am

As I began to work on the inside of the hull and starting to frame out for deck, cabin, and more, I noticed that I had made a few mistakes in the frames that while not very noticeable at first, it produced well over 2.5 inches of change into the dimensions. It's really tough getting all the curves and everything right without being able to trace the patterns and instead just working off the scaled drawings. So I went back to an earlier save where I had completed the frames and forms and nothing else. I reworked the frames the best I could, aside from the top of the raised sheer to the sheer. There was a slight cant to them that I just couldn't get right so I decided that in this instance I'll have to leave well enough alone and continue.It doesn't really change too much of my dimensions, and I will just make sure to keep this in mind as I continue the build and take the walkaround portion into consideration. I don't want to give myself a false sense of figuring it out only to realize as i'm actually building that the less than ~10 degree cant to the raised sheer and sheer was all the difference. From what I was gathering from the scaled drawings it was maybe an inch in variation as it went forward.

As I fixed the frames I decided to see what the spacing would look like at the 27' stretch beside the 25' regular spacing. Then I just continued working on the 27ft frame. I will eventually complete both hulls so there is a decent side by side comparison.

Here's both hulls so far.
27FT3dbuildpic2.jpg
27FT3dbuildpic1.jpg
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Re: TrueGrit/CC Walkaround

Postby JoeM » Thu Oct 26, 2017 5:00 pm

Finally back to about where I was before I noticed the mistake. Still working the 27ft hull.

I have also started modeling some of the tanks and engine dimensions. Rough placement looks like I should be able to hit my goal of at least 100 total gallons, though it will be in 2 or maybe even 3 tanks. When I really start playing around with those pieces i'll post pics of my possibilities.

By the way, Ray Macke, your build pics on your site are coming in so handy as I figure out the inner framework, Thanks!!! Your's and Curt's build/boats are what inspired me to follow through on my build of the True Grit.
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27FT3dbuildpic5.jpg
27FT3dbuildpic3.jpg
27FT3dbuildpic4.jpg
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Re: TrueGrit/CC Walkaround

Postby Bill Edmundson » Thu Oct 26, 2017 6:40 pm

Joe

Many of us stay around after our builds for the pleasure it brings us to help others.

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Re: TrueGrit/CC Walkaround

Postby JoeM » Mon Oct 30, 2017 9:36 pm

Been busy doing a Warrior Sailing Program event. Got some more done on the build. I've begun to be a little less thorough as I'm too anxious to see the spacing of everything. Kind of jumping around and than I have to kinda of go back and at least put in minimal framing to bring it to a more realistic open area. I won't be able to do that with the actual build so i'm letting myself indulge my impatience now while I can. Things are still looking good as far as space goes for major weight items.

I have a few more things to work on with the bunks. The upper bunks need to be widened a bit at the bow. It's only just under 6' long. The lower bunk is longer. Fortunately my wife and I and most of my family are between 5' and 5'10" so that isn't a huge concern.

The bow is not completed. I have it raised mainly to make pulling the anchor solo from the helm easier. I'm still playing with the angles and size.

The rail posts are also not set in stone. I'm playing with heights and contemplating putting paneling on some of them aft of the wheelhouse.
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27ftbunks.jpg
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Re: TrueGrit/CC Walkaround

Postby JoeM » Mon Oct 30, 2017 9:37 pm

was limited to 3 pictures and I have 5. here are the others.


The head isn't complete though there is enough room to do your business.
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Re: TrueGrit/CC Walkaround

Postby JoeM » Fri Nov 03, 2017 7:57 am

Playing with different setups as I refine my design and add in all the framing.

The current setup has a 50 gal water tank and 2 22 gal holding tanks for black and grey water. The reason I don't have full capacity(50gal+) holding tanks is I will be having a freshwater washdown for at least the anchor rode(fishing saltwater mainly) and any other washdown that requires freshwater(not a lot of freshwater needed). The rest of the washdown will be sea water for temporary washdown with a full freshwater wash when done for the day with either dock water or the freshwater washdown at home or boat launch.

I have 2 battery banks comprised of 3 batteries up to type 31 for each bank. There is also room for 2 type 27 starting batteries. Each battery bank is about 300amp hours total and the starting batteries are at least 800 cca. I have a lot of electronics planned and need the capacity. Frankly, I only need one battery bank and one starting battery but as I learned in the military, two is one and one is none, Redundancy is life.

I did move the engine forwards a couple inches from the standard design but am willing to compensate with a longer shaft if necessary. The engine i'm anticipating using is a 3.0l Mercruiser about 135hp. I'd rather have a diesel but budget is saying gas is the best for my use and wallet. There is room for a mercury diesel about 150hp though it's tight in my designed engine room. The other brand engines would require a reconfiguring of my engine room. The walk around I put in definitely limited me in my engine room space available unless I don't care about entering the salon from the cockpit. I had tossed around the idea of a side entrance salon which would leave much more space for an engine. I just couldn't seem to get it right, but i'll keep trying.

I have a total of 146 gallons of fuel in 3 tanks. One 56 gal Belly tank and 2 45 gal Saddle tanks. There is a little room for more but that would require custom made tanks. At a pretty miserable 2mpg this would give me almost 300 miles which is sufficient for the majority of my trips by a long shot.

The weight balance issue has been largely corrected for in placement of tanks and batteries. This was done on paper so I am planning on buying a few hundred pounds of ballast sacks so I can reconfigure the trim if needed and find a way to secure them so they don't move around. But on paper it is mostly balanced, the cg did move aft about 3 inches.

There is actually quite a bit of cabinet space as I said in an earlier post. Also mentioned is the comparative lack of counter space. I will try to add pull out table tops and drink holders and the like to make up for that lack.

I was a little premature with the Bunk setup being workable. I'm finding that the bottom bunk has over 24 inches of headroom, not a lot admittedly but enough. The top bunk is right around 17 inches, and that is not enough. I debated changing the deck beam on frame 7 to allow the bottom bunk to be lower, even though it's built into the frame. I also looked at raising the berth roof but thought that would obstruct visibility unless I also raised the helm, which I already had done and didn't feel raising more would be safe. I'm now looking into maintaining enough space on the bottom bunk and having a slide out foot support that is only needed when the "middle" berth is being used and slid out of the way when not. There is always the salon berth that can be used as well and that has enough space for 2 once put together if they get a little cozy.

Will post more pictures later, I'm also playing with the windshield angle. I'm going with a forward slanted window, what i'm reading is called the west coast style. These windows tend to cut glare from lights, both internal and external, at night. Being a slower boat I intend on launching at 0' dark 30 so I can cruise out to the fishing grounds and make it by first light. So night operations will be extensive and the reduction in glare will be nice. I also want the water and spray to clear the windshield as fast as possible and the angle helps that happen. I had read that west coast style is between 55 and 65 degrees. I personally think that looks like too much so i'm playing around with less, maybe as little as 30 degrees. The other reason for the forward swept windshield is it gives more space on the interior to mount electronics without the windshield getting in the way. I am planning on mounting at least my 2 planned VHF radios to the ceiling and with a rear swept windshield, they would be right above my head instead of right above the dash.
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3dbuild-27ftwatertanks.jpg
3dbuild-27ftcabinetssalon.jpg
3dbuild-27ftbatteriesfueltanksengine.jpg
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Re: TrueGrit/CC Walkaround

Postby kens » Fri Nov 03, 2017 8:40 am

I would not figure the 3.0L engine at 135hp.
More like 120hp at the flywheel, if that, if you get the vortec.
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Re: TrueGrit/CC Walkaround

Postby curtgard » Fri Nov 03, 2017 11:54 am

On my True Grit, I have a 6 degree forward slant on the windshields. I would think that 30 degree would still be too much, maybe more like 15 degree. This may be one of the areas that is designed as you build since the cabin is totally just design and build as you go. What cruise speed are you trying to achieve?

Curt

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Re: TrueGrit/CC Walkaround

Postby JoeM » Fri Nov 03, 2017 2:33 pm

kens wrote:I would not figure the 3.0L engine at 135hp.
More like 120hp at the flywheel, if that, if you get the vortec.
I already been there, done that, got the tshirt.

I appreciate the reminder.
I would think a 15-20hp is not too much of a factor for me and this boat. With a minimum recommended hp of about 60hp to reach speeds of 10kts+ on paper for this hull I think the ~120hp will be sufficient. Only reason I was considering the maximum recommended HP of 150-160 was purely so I had the CAPABILITY of speeds upwards of 16-20mph.

curtgard wrote:On my True Grit, I have a 6 degree forward slant on the windshields. I would think that 30 degree would still be too much, maybe more like 15 degree. This may be one of the areas that is designed as you build since the cabin is totally just design and build as you go. What cruise speed are you trying to achieve?

Curt


I did find 30 degree to be a bit too much. I think the max I'd go is this at 20 degree.
3dbuild27ft20degreewindshield.jpg
I will try other angles as well including your 6 degree. Was there any reason you chose 6 degrees as opposed to 10degrees? I'm wondering if I haven't fully thought through the ramifications of this change and perhaps your reasoning will shed light on what route I should go.

I'm thinking a cruising speed of ~8-9kts(~10mph). As I said in response to Kens, I want the capability to hit ~13-17kts(16-20MPH) when I feel like burning more fuel, or we see fish breaking the surface a mile or two away and want to swoop over somewhat quickly. But by and large I don't foresee cruising speeds above 9kts.
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Re: TrueGrit/CC Walkaround

Postby Bill Edmundson » Fri Nov 03, 2017 3:55 pm

Joe

I run a 125 hp diesel. That's 115 hp US hp, we have bigger horses. At the Gathering on Friday we go to lunch in Chattanooga. It is a 75 mile round trip, about 3 hours run time at about 2500 rpm., average. I use 5-6 gal. of fuel. I know you won't be running that fast. But, just for an idea of fuel consumption.

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Re: TrueGrit/CC Walkaround

Postby curtgard » Fri Nov 03, 2017 5:22 pm

I chose the 6 degree on looks mainly. The cabin side cockpit ends are also at 6 degree to match. With a single windshield, perhaps more forward slant would still look good but really its what the builder thinks look good to him.

Curt

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Re: TrueGrit/CC Walkaround

Postby JoeM » Sat Nov 04, 2017 10:45 am

curtgard wrote:I chose the 6 degree on looks mainly. The cabin side cockpit ends are also at 6 degree to match. With a single windshield, perhaps more forward slant would still look good but really its what the builder thinks look good to him.

Curt



Appreciate your thoughts. Your boat does look good with that 6 degree forward slant. Nice to know I didn't forget something in my reasoning.By the way, what did you use for your windows? A plastic like Lexan or laminated safety glass?

Wish I could say the same in regards to the 6 degree pitch to my cabin sides. Once I deviated from the plans after the flip and the sole I just freeformed it and ended with straight cabin sides and I actually just kept the 14 degree pitch on my sidedeck as I didn't think that would impede balance too much and would help direct all water off the side deck rather than aft and into the cockpit. Plus it wouldn't have multiple angles in the 14 inch walkway. After you brought the cabin side pitch to my attention I somewhat quickly made a version with that change and found that i'm actually kind of partial to the straight sides. Is there any reason, other than aesthetics, for putting in that 6 degree pitch to the sides? I wouldn't think that the aerodynamics would change all that much with that slight of pitch, but i'm not a naval architect. It doesn't really change the area in the boat with my already smaller cabin though it might feel even smaller with the inward pitch of the sides.

And i'm going to stop there for now before I head down the rabbit hole.

Bill Edmundson wrote:Joe

I run a 125 hp diesel. That's 115 hp US hp, we have bigger horses. At the Gathering on Friday we go to lunch in Chattanooga. It is a 75 mile round trip, about 3 hours run time at about 2500 rpm., average. I use 5-6 gal. of fuel. I know you won't be running that fast. But, just for an idea of fuel consumption.

Bill


Thanks for the numbers! That is just crazy, by my calulations that's about 12-15 mpg!!! This is for your Tahoe 19 with Yanmar TurboDiesel correct? I hate to admit that when I first started going through builds I focused mainly on Glen-L Designs, and i'm just working my way through your Bartender build and just looked through their site. Interesting boats and a beautiful build so far, and i'm only on page 4 or so right now.

The only boat I operated that I was responsible for fuel and paid attention to numbers is my brother's 24' skipjack which avg'd 2-3mpg at about 20mph cruise and we were THRILLED at that.
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Re: TrueGrit/CC Walkaround

Postby Bill Edmundson » Sat Nov 04, 2017 11:25 am

Joe,

It's a Yanmar 125 turbo diesel. I have a rectangular tank, 26 gal. The fuel gage is worthless. I measure with a dip stick. Stick says, right at 1/4 tank. I know that sounds ridicules. that includes idle speed up to 38 mph.

However, unless you run a lot, it is hard to justify the extra cost of a diesel with fuel cost. Then there is a safety issue.

Bill
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