Upscaled HMD19

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jonlitts
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Upscaled HMD19

Post by jonlitts »

Hi all!

New to the forum, and to boat building. My kiddos and I are currently working on our second build... a 10' mini tug. My 11yo son has been a lover of boats for most of his life; now, with this build, I'm smitten. My 15yo daughter enjoys helping as well.

After many evenings of conversation with them about which bigger boat to go for next, I'm actually ready to pull the trigger on a set of HMD19 plans.

Forgive my newbie questions. I was wondering about the question of upscaling, and how the associated redesigns work. 10% would make me happy on this model... the main reason being the possibility that adding a slight bit of area might allow for placing an actual head. I have positively no more space to accommodate, for example, the MT24.
  • Is this possible?
    If so, does the builder do the calculations themselves, or are new customized plans generated?
Thanks all! Really enjoying the wisdom and inspiration on the forum!
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Jonathan

jbo_c
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Re: Upscaled HMD19

Post by jbo_c »

Scaling is entirely up to the builder, though you’ll get lots of advice here.

My advice is not to scale. Lots of potential pitfalls in scaling. You’ll also waste a lot of wood/money because the designers here are very good at maximizing efficiency of ply usage. Scaling throws that out the window. - and that doesn’t count things that you cut wrong because you forgot to scale that last measurement. :) I have others but don’t want to seem like I’m being discouraging.

If size and a full head are your main issues, how about the HB series? That one you actually probably could make exactly the length you can fit in your build space and they have full heads.

But . . . many of the designs here can absolutely be scaled. If that really is what you want to do, verify with the designer and go for it. You’ll get lots of good help and encouragement here.

That’s one of my favorite designs on the site. I’d love to see another built - stretched or not.

Jbo

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BarraMan
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Re: Upscaled HMD19

Post by BarraMan »

I think as a general rule, Jacques is OK with upscaling most plans by 10%, but he may advise to add a layer of glass to the bottom. That was his advice to me.
"How do you do it"? Easy, buy the metric plans and multiply the ALL the dimensions by 10%. I wrote the new dimensions on the plans. Double check before you cut!
"adding a slight bit of area"
!! Its easy to say, "I'll up scale by 10%", but you need to understand the reality. It will turn a "big" boat into a "BIG" boat. Something like" 10% bigger in linear dimensions = 20% bigger in areas = 30% bigger in volume. Doing so turned my 20' Mangusta hull into a 22' hull! It will require more of everything - more ply, more glass cloth, more epoxy, probably more power etc etc etc! 8O

Yes, it will mess up the clever nesting diagram that Jacques supplies with the plans, but a few extra sheets of ply are nothing in the overall cost of building a big boat.

If upscaling a HMD 19 fits your mission, then "Do it", I say!

Do I regret upscaling the Mangusta 20 hull to produce my boat? Not for a second!

I luv it and it fits my mission perfectly. I am a week away from heading to a very remote part of Australia in the pursuit of barramundi ! We will be 100 nm from the nearest boat ramp and plan to sleep four on board for a couple of nights at a time.

We are known in fishing circles up north as the blokes with the BIG WHITE BOAT, and among our friends as the blokes with the F@#%ING BIG BARRA BOAT (FBBB for short!) :lol:

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jonlitts
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Re: Upscaled HMD19

Post by jonlitts »

Thank you both very much!

As this would be my first large build, after reading both your comments, and after a couple of nights' sleep on it, I think it wise for me to keep to the plans.

Thanks again!
---
Jonathan

blueflood
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Re: Upscaled HMD19

Post by blueflood »

Hi fellow HMD19 builder !

For cruising, the portable toilet is a real luxury. We have used it on a few occasions now. If you have a folding door or similar to shield the berth where the toilet sits, it provides total privacy.

If you want to stretch the boat just because of a full head, save yourself labor and extra time, never mind cost. Stick with simple😁. It works.

We have a basic toilet with ample sitting headroom in berth, water tanks (hand pump / sink) propane camping stove and removable BBQ. The toilet can be positioned in the cockpit for overnight sleeping.

Save the cash for must haves 👍🏻
The HMD19 provides tons of volume as-is for everything. She is huge.

If anything, I suggest you consider a 3 bow sunshade for the cockpit and comfy chairs when piloting. Also stick with a high trust 10 hp outboard.

Loads of fun you will have.

Marc

jonlitts
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Re: Upscaled HMD19

Post by jonlitts »

blueflood wrote: Tue Nov 01, 2022 10:20 am Hi fellow HMD19 builder !

For cruising, the portable toilet is a real luxury. We have used it on a few occasions now. If you have a folding door or similar to shield the berth where the toilet sits, it provides total privacy.

If you want to stretch the boat just because of a full head, save yourself labor and extra time, never mind cost. Stick with simple😁. It works.

We have a basic toilet with ample sitting headroom in berth, water tanks (hand pump / sink) propane camping stove and removable BBQ. The toilet can be positioned in the cockpit for overnight sleeping.

Save the cash for must haves 👍🏻
The HMD19 provides tons of volume as-is for everything. She is huge.

If anything, I suggest you consider a 3 bow sunshade for the cockpit and comfy chairs when piloting. Also stick with a high trust 10 hp outboard.

Loads of fun you will have.

Marc
Hi Marc!
Your build in particular is one that I've been pouring over, reading through each morning over my coffee. :) Thanks for the reply! I can't tell you how many hours I (we... kids and I) poured over the different models. But guess what... I actually just bought a set of MM21 plans this morning! For three of us taking any sort of trip, it just makes sense for a few reasons. Of course, I do realize that by the time I'm done with any build, they may have lost interest. :lol: Thank you again, and thanks for the wisdom I've gleaned from your posts!
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Jonathan

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Dougster
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Re: Upscaled HMD19

Post by Dougster »

Great--I've always liked that design. Looking forward to your build thread for sure!

Dougster

blueflood
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Re: Upscaled HMD19

Post by blueflood »

Hi jonlitts, Dougster 👍🏻

Have fun on the MM21 project with the young crew ! Of course post tons of photos during and ask away when unsure.

One thing if I may 😁 it is very easy to start spending and overspend on boats. Work out your absolute needs with costs and do not go over. Have a max dollar ceiling for a total boat and stick to it.

Dougster...fun season. I really got the handling and feel of Penny. I was a bit intiminated at the beginning with her size but now it is like driving a station wagon on ashphalt. I love how she plows the waves.

Marc

jonlitts
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Re: Upscaled HMD19

Post by jonlitts »

blueflood wrote: Thu Nov 03, 2022 9:55 pm
One thing if I may 😁 it is very easy to start spending and overspend on boats. Work out your absolute needs with costs and do not go over. Have a max dollar ceiling for a total boat and stick to it.

Marc
Thanks Brother. Yes, I can definitely see where that would be a tendency. I like to save a buck, but not at the expense of putting quality in jeopardy (i.e., although these plans state ACX is acceptable building material, I will definitely be using proper marine ply... at the very least on all hull components).
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Jonathan

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Re: Upscaled HMD19

Post by pee wee »

You're right about the plywood!

I think the suggestion about ACX was made so long ago that it refers to a quality of plywood that doesn't exist anymore.
Hank

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