Dream Builder

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JoeM
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Dream Builder

Postby JoeM » Wed Sep 20, 2017 3:44 pm

Hi everyone.

Been lurking for a while, soaking up as much information as possible. I live in Santa Clarita, CA, north of Los Angeles. I'm a disabled Navy Corpsman so building a boat and buying materials as I go is a lot more feasible than buying new as I'm on a fixed income but have plenty of time and skills on my hands. I have not settled on an actual plan but i'm leaning towards a Coastal Cruiser/True grit hull and am about to order the study plans to see if it's right for me and the changes I hope to make. I will definitely post my thoughts on here once I put it together and see if i'm on the right track.

Other options I looked at are the A-lure and the Double Eagle but I think these aren't the best compromise for what i'm looking for.

I looked at the builds on here and they inspire me. I'm still in the dreaming/planning phase and it's nice to know there is a place I can go for advice. I'll go into detail about what i'm looking for specifically and changes I'm thinking of making later.

For now I just wanted to say hi and introduce myself. Will be working on my profile in the days to come as well.

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Ibrew2be
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Re: Dream Builder

Postby Ibrew2be » Wed Sep 20, 2017 5:50 pm

Welcome, Joe. Keep us posted on what you decide. It would be great to be able to follow your build.

Barry
Barry Shantz

Imp built and launched. Thinking hard about Boat 2.0

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JoeM
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Re: Dream Builder

Postby JoeM » Thu Sep 21, 2017 6:40 pm

Thanks Barry.

I will definitely document the build once it happens. Might be a while.

I have a couple books and the Coastal Cruiser study plans coming soon courtesy of Glen-L. I figure before I get too far ahead of myself I should read the books and study the plans before I start making changes. Who knows, after I read the books I may decide a different design is better for me.

I'm also still working through the forums and all of the great builds. Lots of inspiration here.

Joe

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Ibrew2be
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Re: Dream Builder

Postby Ibrew2be » Fri Sep 22, 2017 5:02 pm

I hope that one of the books you're planning to read is Boat Building with Plywood. It is a great resource, and many builders have benefited from having read it.

Barry
Barry Shantz

Imp built and launched. Thinking hard about Boat 2.0

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JoeM
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Re: Dream Builder

Postby JoeM » Sat Sep 23, 2017 2:01 pm

Yes sir! I am reading through Boat Building with Plywood. I'm probably going to get the book about inboards soon as well.

I'm reading through Boat Building while also looking at the Coastal Cruiser study plans. I may need to get the True grit study plans as my build will sort of be a cross and I was hoping to go with the direct-drive inboard vs. V-drive, and the CC study plans are v-drive. My reasoning for that is the placement of the motor as I'm utilizing the boat for fishing and am planning on a 50-60gal(min) baitwell/livewell on top of the deck and flush deck iceboxes with pumpouts where space allows. I think the additional weight of all of that in the stern area in addition to a v-drive setup where the engine is sitting further back is poor weight management and feel that having the direct drive inboard forward closer to the CB it would be better. Am I wrong in thinking that way? I'm also not 100% set on this option, just leaning that way for now. I still have a lot of research to do on engines and drive systems.

On of the unknowns of the CC/TrueGrit design that could change my thinking is the fuel tank location and how that plays into the weight balance as it wasn't spelled out in the study plans where the tank is supposed to be located. My guess, looking at the Coastal Cruiser study plans, is the the fuel tank is supposed to be fitted anywhere from frame 5 all the way back to frame 2. Perhaps Ray or Curt could chime in here if they see this? I was hoping to put a tank closer to 80-100gal and drop the freshwater to 20-25 gal. I'm working on a drawing that will hopefully explain my setup fully. It won't be so much for long range cruising as it will be for fishing and cruising for a up to a couple days at a time(ideal range ~300 miles. I wanted something that would be comfortable cruising around 10mph and as fuel effiecient as possible but with the ability to get up to 20mph if it deemed necessary, but honestly my body is not cut out for the pounding of a planing boat so slow and steady is good for me. Was going to look for an engine in the 125-150hp range so I can have the option of more speed at expense of fuel. I was also going to stretch it to 27'.

I liked the looks of the true grit/CC design and I feel the changes I plan on making are best made on this design rather than one of the others. I may be wrong and am still keeping my options open.

I should probably give a little info on my boating experience. I have driven quite a few different boats in my 33 years of life. Most recently I had been operating my brother's 24' Skipjack open cruiser. Had a SBC putting out about 300hp through a volvo duoprop, the 290 I believe. We took it out of Channel Islands Harbor in Oxnard,CA and fished around a couple islands 10-20 miles from mainland many times. I've also operated a few different pontoon boats up to 22', a few jet skis, and a couple small ski boats on lakes. I've also done a little sailing in a J-22(Thanks Warrior Sailing Program!) and one time I crewed a 10m Flying Tiger race boat. I'm not an expert by any means but i'm comfortable in my seamanship. I have yet to operate a semi-displacement inboard boat but have ridden in a few larger boats with similar hulls and have seen quite a few operating in the same area in the size i'm thinking of building.

Back to my research.

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NAMEngJS
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Re: Dream Builder

Postby NAMEngJS » Mon Sep 25, 2017 10:35 am

In regards to your thinking on the Inboard Vdrive location i would take considerable amounts of time to consider any major move. The designer has a vessel that should float at its designed trim with the weights as shown. The LCB can and will change with the movement of any weight. Imagine haveing 10 lbs on either end of a see saw and then taking one of the weights and moving it to the pivot point. The 10 lbs you left on one end will go down to the ground. Moving a major weight such as the motor would have to be offset by equal weight movement elsewhere to maintain the LCB as close to the designed location.

If your intention is not to modify the design, but to start with one designed with an inboard nearer the LCB then the problem becomes easier as you would only need to ensure that all your proposed modifications are not overweight and all at one end. The designers have left margin in the designs to allow for some creative license.

In either case, for consumable liquids, since the volume will be constantly variable it is best (though not always feasible) to put tanks as close to the LCB as well. The idea being that as a liquid is consumed (or added if waste tank) the net effect would be that the vessel does not experience significant increase in trim either by the bow or stern.
All men dream, but not equally. Those who dream by night in the recesses of their minds, wake to find that it was vanity: but the dreamers by day are dangerous men, for they may act on their dreams with open eyes, to make them possible.

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JoeM
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Re: Dream Builder

Postby JoeM » Mon Sep 25, 2017 11:08 am

Thanks for reminding me about the weight and CB! I welcome any and all advice!

The Coastal Cruiser and the True Grit are based on the same hull. The differences between the two designs appears to be the way the cabin is laid out and the smaller water tank and bigger fuel tank. In the CC there is a step down into the living/galley area and a couple steps up into the pilot house area. The True Grit does not have that step down or the step up which is what I believe allows for the straight inboard instead of a bobtail setup, in addition to moving/changing fuel/water tanks. I'm actually trying to decide if I should just get the actual plans instead of the study plans for the True Grit . Hopefully it is a little more detailed in giving dimensions so I can build a design on computer rather than torture myself drawing my idea by hand.

I've read through Boatbuilding with Plywood a couple times, and working on my third, and I do realize the changes of location of major weight objects(motor, fuel, water, batteries, etc.) and how it changes in relation to the distance from the CB. I'm making a weight list of all proposed changes and will post that along with my drawings of my concept. I am terrible at drawing so it is taking me time to get it on paper and actually look like a boat. Just from a mildly educated guess and my rough calculations, it looks promising for now.

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curtgard
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Re: Dream Builder

Postby curtgard » Mon Sep 25, 2017 4:28 pm

On my True Grit, I have a 180 gallon fuel tank located between frames 3 and 4 with a 130 gallon water tank located between frames 4 and 5. As per the plans, the CB is approx. 9" aft of frame 4. The plans show the location of an inboard between frames 2 and 3 with the weight limited to 850 lbs. on the 27' version. I lengthened the hull to 29'6" and added an add'l 2' swim platform that is actually part of the hull making the boat 31'6". My outboard motor is mounted to the swim platform with the motor weighing 425 lbs. My house and start batteries are located between frames 4 and 5. With these changes to the design, I ended up with a boat that sits level but a couple inches lower than the plans show.

I think that most people that have built this design find that their boat ends up being stern heavy. So, the more weight that you can move forward, the better. With this said, then I think your fuel tank would need to be between frames 4 and 5. You may still have a problem with a 500+ lb. livewell tank and a 800 lb. motor aft of the CB with only a fuel tank and smaller cabin forward of the CB. I think things would work out the best if the bait tank was located near the CB. With an inboard, there will be a motor box taking up some deck space. Lots of things to think about.

Curt

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JoeM
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Re: Dream Builder

Postby JoeM » Mon Sep 25, 2017 5:25 pm

curtgard wrote:On my True Grit, I have a 180 gallon fuel tank located between frames 3 and 4 with a 130 gallon water tank located between frames 4 and 5. As per the plans, the CB is approx. 9" aft of frame 4. The plans show the location of an inboard between frames 2 and 3 with the weight limited to 850 lbs. on the 27' version. I lengthened the hull to 29'6" and added an add'l 2' swim platform that is actually part of the hull making the boat 31'6". My outboard motor is mounted to the swim platform with the motor weighing 425 lbs. My house and start batteries are located between frames 4 and 5. With these changes to the design, I ended up with a boat that sits level but a couple inches lower than the plans show.

I think that most people that have built this design find that their boat ends up being stern heavy. So, the more weight that you can move forward, the better. With this said, then I think your fuel tank would need to be between frames 4 and 5. You may still have a problem with a 500+ lb. livewell tank and a 800 lb. motor aft of the CB with only a fuel tank and smaller cabin forward of the CB. I think things would work out the best if the bait tank was located near the CB. With an inboard, there will be a motor box taking up some deck space. Lots of things to think about.

Curt


Thanks for the information Curt! Your build is outstanding and one of the reasons I liked the design so much! If I can get something put together half as good as you did I'll be happy!

I really appreciate the location information especially and am taking that all into account with my setup. Is there any reason a 30-40 gallon water tank,shaped correctly, would not be able to be put under the bed at the bow? I know it's only 250-300lbs but being placed as far forward as frame 7 would that not help counter some of that excess weight of the livewell? Being only 250-300 lbs I would not expect it to put too much stress on the forward frame/hull, but i'm still early in my design. Drawing is difficult for me so until I can get it looking like a boat and able to convey my design effectively, I'll just keep working on it.

I have a bunch of house projects going right now and a battle with gophers but I hope to have my design flushed out, drawn up, and posted for everyone's advice within a week or so.

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curtgard
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Re: Dream Builder

Postby curtgard » Tue Sep 26, 2017 5:53 pm

I see no reason a fresh water tank couldn't be located in the berth area. It would be helpful for you to figure your weight balance from the CB on your proposed tank and engine locations. A search on the internet will tell you how to do that calculation or it may tell you someplace on the Glen-l site.

Curt

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JoeM
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Re: Dream Builder

Postby JoeM » Wed Sep 27, 2017 12:58 pm

That CB you were talking about 9" behind frame 4, that's for the standard 25' inboard plans?

So once I stretch the 10% to 27'6" I will have to redo the CB calculations? It adjusts each frame by about 4-5" and I am not planning on changing the engine location or putting one heavier than the 850lb from the design so my guess is it would still be relatively close to the designed CB. Then the fun begins trying to balance the weight fore and aft. It gets really interesting when trying to also balance athwartship, though i'm not quite there yet.

I saw an example in the Boat Builders Notebook about how to assign weight based on position in relation to CB. Take the weight multiplied by the distance from CB(in ft.). Add up everything in front of CB. Add up everything behind CB. And compare the two. Goal is to get them roughly even.

How far out of balance can they be and still be somewhat in trim? I'm wondering what the others CB weight balance is since you said most of those building this design sit lower in the stern. To use your's as an example again, your 425lb outboard is maybe 12-14 feet(guessing) from the CB giving it a weight value of close to 5,000lbs. Your fuel tank sits almost on the CB so it doesn't really change the value. Your 130 gal Water tank is maybe 2-4 feet in front of the CB giving it a value of between 2,500-5,000lb value if full. Not taking anything else into consideration it's either an even value or a stern heavy value of 2,500lb. Yes I oversimplified it as there are many more things that needed to be added up(batteries and more) to get a real idea of balance, but the idea is still the same.

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Bill Edmundson
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Re: Dream Builder

Postby Bill Edmundson » Wed Sep 27, 2017 1:16 pm

This is not a difficult calculation. Pick a spot, any spot. Take the major weights and multiply by their distance from that spot. Now, add those numbers up and divide by the their total weight. This will give you the cg of the equipment from the spot.

Weights behind your spot are negative, weights in front of your spot are positive.

Bill
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JoeM
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Re: Dream Builder

Postby JoeM » Wed Sep 27, 2017 3:51 pm

I'll go ahead and try to work through this. Maybe this will help others as well work through their own design. Might be hard to visualize where it fits but this a rough estimated weight breakdown by frame. Very rough estimates.

Transom
Rudder & assembly - 20 lb x 12 back = -240
Light storage - 15lb x 12 back = -180

Frame 1
Ice Hold - 300lb x 10 ft back = -3000
Ice Hold x2 300lb x 10 ft back = -3000
Bait Tank - 500lb x 10ft back = -5000

Frame 2
Motor - 850 x 6ft back = -5100

Frame 3

CB frame 4 - 9"
Fuel tank 110 gal -centered on cb so no change

Frame 4
Starter Battery - 50lb x 2ft forward = 100
Starter Battery x2 - 50lb x 2 ft forward = 100
Charger - 10lb x 2 ft forward = 20

Frame 5

Batt bank #1 - 100lb x 5ft forward = 500
Batt bank #2 - 100lb x 5ft forward = 500
Toilet and sink - 30lb x 5ft forward = 150
Frame 6

Bunk bed - 30lb x 8 ft forward = 240
Cabinet - 40lb x 8 ft forward = 320
GW tank - empty
BW tank - empty

Frame 7
Freshwater tank 30-40gal - 250lb x 10ft forward = 2500
Anchor + rode(25ft chain+300ft line) - 40lb x 12ft forward = 480
Anchor + rode x2(25 ft chain + 300 ft line) - 40lb x 12 ft forward = 480
Bow

adding this up this is what I get.

-16,520+5390 = -11,130

When you said divide by their total weight, do you mean the total weight of the adjusted values or the actual weight?

divided by total adjusted weight
-11,130/21,910 = -0.52

Divided by total weight

-11,130/2,725 = -4.08

It is obviously not in balance, but by how much? What does this number mean exactly? As in, the stern will sit 4 inches lower? Or does the CG shift 0.5 ft back? I apologize for my lack of understanding here.

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Mr Hot Rod
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Re: Dream Builder

Postby Mr Hot Rod » Wed Sep 27, 2017 5:04 pm

JoeM wrote:What does this number mean exactly? As in, the stern will sit 4 inches lower?

1) Add the weights of all objects. Add the weight moments.
2) Divide the total moment by the total weight. This is the distance from the datum to the center of gravity.

Here are some links to augment Bill's post :

    → For a sample Hull Balance spreadsheet and Weight Moment Study :

    → Info on how to stretch a hull :

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Bill Edmundson
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Re: Dream Builder

Postby Bill Edmundson » Wed Sep 27, 2017 6:11 pm

It is weight times distance divided by weight. That will give you a distance. A few inch ins will sink you.

Bill
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