Glacier Boats of Alaska - Builder's Forums

Great Alaskan and Boat Building => Projects - Glacier Boats of Alaska boat projects => Topic started by: Scott L on March 20, 2021, 05:48:21 PM

Title: Building a 27'-0 GA
Post by: Scott L on March 20, 2021, 05:48:21 PM
Hello, here are some pics of my start.
Title: Re: Building a 27'-0 GA
Post by: Grady300 on March 20, 2021, 06:24:22 PM
Looking good so far, looks like you have plenty of room in your shop for the build. Being able to spread out some really helps.
Title: Re: Building a 27'-0 GA
Post by: json on March 20, 2021, 08:02:30 PM
Very cool, can't wait to watch your build progress! Get after it!
Title: Re: Building a 27'-0 GA
Post by: Djeffrey on March 20, 2021, 08:44:25 PM
Congrats on your start. Nice scarf! Where are you building, what state.
Title: Re: Building a 27'-0 GA
Post by: Scott L on March 20, 2021, 08:53:53 PM
My wife and I are in Bandon OR. We retired last year so I have time for the build.
Title: Re: Building a 27'-0 GA
Post by: Rbob on March 20, 2021, 09:37:01 PM
Scott,

Congrats on the boat build, retirement and welcome to the forum,  you are starting out looking like a pro.

Keep the pics coming!

Rbob
Title: Re: Building a 27'-0 GA
Post by: Todd j on March 21, 2021, 08:58:16 AM
Welcome Scott, what model are you building?
Title: Re: Building a 27'-0 GA
Post by: Scott L on March 21, 2021, 09:53:30 AM
Hello Todd. The model is a sketch of what I envision the boat to look like sort of a Newport. Our use for the boat will mainly fishing but we want to travel up and down the coast line also.
Title: Re: Building a 27'-0 GA
Post by: Todd j on March 21, 2021, 06:56:27 PM
Nice, I like it!
Title: Re: Building a 27'-0 GA
Post by: ghelland on March 21, 2021, 08:37:55 PM
Its always good to see another boat coming to life.  Being retired will help with the build time a lot.  In September a few complete boats will be at the wooden boat festival in Port Townsend Washington.  That might be good timing for you to see what the other guys have done with there houses.
Title: Re: Building a 27'-0 GA
Post by: Scott L on March 21, 2021, 10:04:39 PM
thanks for the info about the boat show. My hats off to all builders who work all week and build in there spare time. I have been waiting for a couple years for this build so I'm enjoying the process.
Title: Re: Building a 27'-0 GA
Post by: Scott L on March 23, 2021, 09:17:51 PM
Thanks Brian for your help, I am still figuring out this site.
I am putting down epoxy and glass on the transom and shelves today. Things seem to have come to a snails pace now. Just enjoying the project.
Title: Re: Building a 27'-0 GA
Post by: Grady300 on March 24, 2021, 10:54:28 AM
Thanks Brian for your help, I am still figuring out this site.
I am putting down epoxy and glass on the transom and shelves today. Things seem to have come to a snails pace now. Just enjoying the project.
Be sure not to glass anything that needs to bend (outside bend, inside bend is fine) when put it on the boat. You can glass the underside of the shelves or the inside of the side panels prior to installing on the boat. Basic rule is only glass the inside of a bend, if you glass the outside of a bend it doesn't bend too well. Hope that makes sense. You will save a lot of overall time on the build by glassing everything you can prior to installing in the boat. 
Title: Re: Building a 27'-0 GA
Post by: Scott L on March 24, 2021, 06:21:26 PM
Thanks for the advice Chuck, I Knew that glassing the outside of the curve could be a problem but I did it anyway, hopefully I wont be sorry. Brian talks about glassing the bottom side of the shelves so I'm assuming it has been done before. It is a fairly long limber piece . Cross my fingers.
Title: Re: Building a 27'-0 GA
Post by: Scott L on March 24, 2021, 06:35:30 PM
Glassed shelves
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on March 25, 2021, 07:31:51 AM

It's definitely easier to glass the bottom of the shelves before installation, but you're right, it does break the rule that Chuck mentions.  The curves that the shelves have to conform to are mild enough so it doesn't make a big difference.  If it does, with your wood and glass selection, just use clamps to draw the shelves down to the molds.

bd

Title: Re: Building a 27'-0 GA
Post by: Todd j on March 25, 2021, 09:30:50 AM
I do know remember if it’s required or not, but I thought it was nice to glass the shelves to the sides after the flip.   
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on March 25, 2021, 03:39:57 PM

It's not required to glass the shelves before installing them ... plan on doing it when it is EASIEST for you given your own shop layout and timing.
Title: Re: Building a 27'-0 GA
Post by: Scott L on March 25, 2021, 03:46:49 PM
No problem with the pre glassed shelves, they had plenty of flex .
Title: Re: Building a 27'-0 GA
Post by: Grady300 on March 25, 2021, 10:14:10 PM
I do know remember if it’s required or not, but I thought it was nice to glass the shelves to the sides after the flip.
That's what I did also
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on March 26, 2021, 06:15:15 AM
I do know remember if it’s required or not, but I thought it was nice to glass the shelves to the sides after the flip.

Yeah ... two different topics here.  First, glass what will be the bottom face of the shelves and the inward (rounded for glassing) edge before installing shelves.  Later, once the boat is upright, you trim the side panels flush with the (now) top face of the shelves, router, and glass.  Some install a toe-rail around the forward 2/3rds of the boat before glassing the side-to-shelf seam so that they both get glassed at once.
Title: Re: Building a 27'-0 GA
Post by: Djeffrey on March 26, 2021, 07:41:31 AM
Glass before install. You won’t regret it.
Title: Re: Building a 27'-0 GA
Post by: Todd j on March 26, 2021, 04:17:46 PM
Glass before install. You won’t regret it.
ya.  What he said
Title: Re: Building a 27'-0 GA
Post by: Scott L on April 04, 2021, 09:27:05 AM
Making some head way, Scarfed the side panels, Bottom panels and built the transom. The pieces fit together well and I am ready to start adding epoxy glue. I tied the flat chines to the bottom before any epoxy to ensure that the pieces fit naturally together. 
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on April 04, 2021, 05:53:20 PM

Beautiful work!  You can tell by how nicely all the parts fit together!

Title: Re: Building a 27'-0 GA
Post by: Grady300 on April 04, 2021, 07:29:38 PM
Amazing how well the parts fit every time, plans well done help so much! Looks great!
Title: Re: Building a 27'-0 GA
Post by: Rbob on April 25, 2021, 05:46:13 PM
It does look awesome, you can tell its going to be a great build.


tagged.
Title: Re: Building a 27'-0 GA
Post by: Scott L on April 25, 2021, 07:11:10 PM
Thanks for the good words, I am enjoying every minute of the build. After some time doing other side projects and a little fishing I am back at working on the boat. Who knew being retired would be so busy . Here I am on the left and my good friend turning the bottom over the lines look great upside down.
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on April 25, 2021, 09:20:44 PM


Looks awesome from here!  Nice to put a face behind the name too!

Title: Re: Building a 27'-0 GA
Post by: Grady300 on April 26, 2021, 06:22:36 PM
Good looking glass work, going to be another beautiful GA
Title: Re: Building a 27'-0 GA
Post by: Scott L on May 01, 2021, 10:01:09 PM
Do to other projects this last couple of weeks progress has been slow but I had a chance to work on the boat today. I could not bring my self to drill holes in the keel so I made some strong backs to lift the bottom off the jig.
Title: Re: Building a 27'-0 GA
Post by: Scott L on May 12, 2021, 07:48:32 PM
Hello everyone, a little update on the build. Glued the bottom to the transom, stringers and bow stem. I finished the second layer of plywood on the hull today.
Title: Re: Building a 27'-0 GA
Post by: Scott L on May 12, 2021, 07:57:54 PM
    More photos
Title: Re: Building a 27'-0 GA
Post by: Rbob on May 12, 2021, 08:26:52 PM
Looking good, you are making lots of progress so pat yourself on the back!
Title: Re: Building a 27'-0 GA
Post by: json on May 12, 2021, 08:32:38 PM
Nice work, looking great! I have shop envy, your shop is HUUUUUGE!
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on May 13, 2021, 05:48:33 AM

You're doing nice work ... your attention to detail shows.  You're going to have a fine boat!

Title: Re: Building a 27'-0 GA
Post by: Scott L on May 13, 2021, 08:27:38 AM
Yup, having lots of room is nice. thanks for the good woods.
 I would like to start asking about engine size. I am thinking 200 single or 115 twins I haven't decided. Is the 200 adequate for big water. I would like to here from some of the boats running on the water for their opinion.
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on May 13, 2021, 08:56:11 AM
Yup, having lots of room is nice. thanks for the good woods.
 I would like to start asking about engine size. I am thinking 200 single or 115 twins I haven't decided. Is the 200 adequate for big water. I would like to here from some of the boats running on the water for their opinion.

Butch, Myrtle Creek, Oregon says his 26-footer and 140hp Suzi works fine but grunts a little on hard turn into a big wave.  I'd say that's too small.  I'd say 175 hp minimum for your 27-footer and the 200 would be a best overall answer.  Those with 225 are happy, and those with 250+ say they can't use all of the throttle except during a hole shot.  Just a little feedback that I've heard ...

Brian

Title: Re: Building a 27'-0 GA
Post by: Scott L on May 13, 2021, 09:17:09 AM
I have leaned toward the 200 all along, when crossing the bar I need plenty of power on hand when needed.
Title: Re: Building a 27'-0 GA
Post by: Todd j on May 13, 2021, 01:09:43 PM
6. Given that I achieved the boat's design planing speed at around 3500 rpm, I cannot imagine this boat with a 200 hp engine - it would be revved up awfully high just to get to cruise, and have little left for heavy loads or a bit of additional speed, and I would think fuel economy would suffer. Seems like 250 is perfect for the 28.


This was posted by Dan B.  He built as light as anyone I have seen.  He pulls it with a toyota SUV IIRC. I would say based on Dan's comments re: other stuff that you could take this to the bank!
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on May 13, 2021, 01:59:42 PM
I have leaned toward the 200 all along, when crossing the bar I need plenty of power on hand when needed.

It would be fine with 200, but as Dan Boccia pointed out, extra is not a bad thing either.  I'd go with the 200, personally, but 225 wouldn't be a bad decision.
Title: Re: Building a 27'-0 GA
Post by: json on May 13, 2021, 04:03:54 PM
For me the decision largely came down to the most power for a given weight. Yamaha v6 f225, f250, f300 motors are all the same block, and weigh the same more or less, so really having as much power on demand for a given weight to push the boat against angry seas / ie holeshot was my priority. Twin 4 strokes would have been much heavier than I wanted to go, but twin 2 strokes could have been ok. Of course that power comes at a $ cost too, but for a one time investment it seemed like a reasonable thing. The inline 4 cyl f200 is lighter, so if that was an option for me then I would have considered that too, but I don't think that is enough for my boat... I haven't seen how overpowered my rig is yet with the 300, maybe I will think my logic is crap here in a couple months hahaha...
Title: Re: Building a 27'-0 GA
Post by: Djeffrey on May 14, 2021, 10:43:09 AM
When all else fails read the instructions, or in this case listen to the instructor. I listened to Brian and went with a 200 Yamaha on my 28 and have not regretted it. It is a perfect fit for this boat.
Title: Re: Building a 27'-0 GA
Post by: Scott L on May 14, 2021, 12:42:26 PM
I've read the instructions carefully and I take what Brian said seriously but we are not in Colorado. The bar crossing I use is one of the worst on the west coast. Engine decision is critical.
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on May 14, 2021, 01:41:07 PM
I've read the instructions carefully and I take what Brian said seriously but we are not in Colorado. The bar crossing I use is one of the worst on the west coast. Engine decision is critical.

B10 / Columbia River Bar?  Tillamook and the never-dredged-enough bar?  LOL ....

You have more reason than most to round up a little ... like the 225 hp?

Title: Re: Building a 27'-0 GA
Post by: Scott L on May 19, 2021, 06:44:40 PM
Blocking and framing on the boat. I glassed the side plywood today. Excided about hanging the sides
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on May 20, 2021, 06:07:51 AM

Nice, clean, professional work!  Your boat's looking fantastic!

Title: Re: Building a 27'-0 GA
Post by: Scott L on May 20, 2021, 09:06:22 AM
It has been a fun project, Thanks for the great drawings it makes the build go smoothly.
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on May 20, 2021, 09:57:45 AM
It has been a fun project, Thanks for the great drawings it makes the build go smoothly.

Thank you!  Let me know if you ever spot an error, a missing piece of info, or something confusing in the manuals or drawings - This is why I make perpetual downloads available to people.  If an issue is found, I fix it and post updated docs at our website.

Brian

Title: Re: Building a 27'-0 GA
Post by: Grady300 on May 23, 2021, 06:47:53 AM
I've read the instructions carefully and I take what Brian said seriously but we are not in Colorado. The bar crossing I use is one of the worst on the west coast. Engine decision is critical.
I have crossed the Columbia bar many times, a little extra HP is a good thing. I would go with twin 115HP on your 28 footer. That was what I originally was going to go with on my 31' Kodiak. I ended up ordering twin 140hp Suzuki's mainly because I felt I needed to get the motors on order with the short supply of new engines out there. I would have liked to waited to weigh the boat first then calculate my power needs but then I could be waiting 6 months for motors to show up. Going with 140 Suki's over 150's Yamaha's saved me 5k and 180 pounds of weight. I didn't thing 20 more hp was worth the extra money and weight.
Title: Re: Building a 27'-0 GA
Post by: Scott L on May 23, 2021, 08:30:41 AM
I am still trying to decide whether to go with twins or a larger single with a T-25 kicker. I'm adding up the pros and cons on each, weight, fuel, cost and what would work best with how we fish. I still have time and assuming the shortage thing will be worked out by that time. Yamaha is probably what I'm going with but the Suzuki motors sound interesting.I Here a lot of good things about Suzuki's.
  Here are a couple of pictures of work this week.


Title: Re: Building a 27'-0 GA
Post by: Scott L on May 23, 2021, 08:39:37 AM
Here is a trick that worked well for me and was a very simple way to hold the shelf from being moved while hanging the side panel . Screw a piece of 1/8" door skin to the shelf and have it touch the floor . It made the shelf very secure.
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on May 23, 2021, 08:50:45 AM

Wow ... you're doing beautiful work!  You're going to have hardly any fairing work to do!  Love the door skin trick too ... that's one for Facebook! (I'll post in a few hours ... church and shopping to do ... )
Title: Re: Building a 27'-0 GA
Post by: Scott L on May 23, 2021, 07:59:03 PM
Thanks , a little attention early on save labor later although I'm not building a piano just a fishing machine. My intension is to get the basic boat done and motors hung,( fingers cross this winter) then in the off season each year add a little more comforts.
Title: Re: Building a 27'-0 GA
Post by: RCPDesigns on May 23, 2021, 08:24:26 PM
Great tip, will definitely be using that one day.
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on May 24, 2021, 07:05:03 AM
Thanks , a little attention early on save labor later although I'm not building a piano just a fishing machine. My intension is to get the basic boat done and motors hung,( fingers cross this winter) then in the off season each year add a little more comforts.

I think that's the best approach.  And it lets you add and tune what the boat is according to your own real experience ... it's hard to think of every little thing in advance and to get it perfect on the first pass. 

Title: Re: Building a 27'-0 GA
Post by: Scott L on July 09, 2021, 09:49:15 AM
It has been awhile, I have been lost in the valley of glass, epoxy and sanding. the hull is getting close to bottom paint. I have decided to apply the rub / spray rail after the boat flip . The transom will be cut out after the roll and rail applied . It will be nice to get back to building again.
Title: Re: Building a 27'-0 GA
Post by: Grady300 on July 09, 2021, 09:38:41 PM
Looking good!! Wait till you flip it, she will be gigantic!!
Title: Re: Building a 27'-0 GA
Post by: Rbob on July 09, 2021, 10:44:57 PM
Scott, good to see the update, you are doing a stellar job, cant wait to see more.
Title: Re: Building a 27'-0 GA
Post by: Scott L on July 10, 2021, 09:19:09 AM
It will be nice when the boat is flipped, getting tired of glass and epoxy work ready to start cutting wood again. How long have people been letting the epoxy cure before primer coat.
Title: Re: Building a 27'-0 GA
Post by: Rbob on July 10, 2021, 09:46:05 AM
I would give it a week before priming, I think the point is the epoxy is cured which is based upon temp and time.

There maybe info in this epoxy book: https://www.westsystem.com/wp-content/uploads/GougeonBook-061205-1.pdf (https://www.westsystem.com/wp-content/uploads/GougeonBook-061205-1.pdf)
Title: Re: Building a 27'-0 GA
Post by: Scott L on July 10, 2021, 12:45:16 PM
Yeah Thanks that's kinda what I was thinking, I will give RAKA a call Monday to see what they think.
Title: Re: Building a 27'-0 GA
Post by: Grady300 on July 11, 2021, 09:09:02 AM
Yeah Thanks that's kinda what I was thinking, I will give RAKA a call Monday to see what they think.
I will be interested in hearing what they have to say! I would think a couple of days would be fine. As long as you use a compatible bottom primer/paint designed to work with epoxy/glass boats. If anything you might even get a chemical bond, don't really know. Truthfully though I have no idea if you should wait 7 days or not, those are just my own thoughts. I never asked the question so it will be good to hear what RAKA says!!!
Title: Re: Building a 27'-0 GA
Post by: Scott L on July 11, 2021, 06:01:35 PM
Thanks Chuck, I will pass along what the epoxy company says I think I'll give the paint company a call as well. It's ok if I wait a week other projects are needing some attention.
Title: Re: Building a 27'-0 GA
Post by: Scott L on July 14, 2021, 07:21:50 PM
I finally got around to calling RAKA epoxy company today. They suggested 4-5 days to let the epoxy cure before paint. Sand and wash before painting.
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on July 15, 2021, 06:10:44 AM

You can never be too careful with painting ... it's the very WORST thing if it goes wrong!

Title: Re: Building a 27'-0 GA
Post by: Scott L on July 15, 2021, 09:25:59 PM
You got that right, one of my biggest fear is the paint going sideways creating a mess. I will follow the directions to a tee.
Title: Re: Building a 27'-0 GA
Post by: Rbob on July 15, 2021, 10:46:44 PM
Fear not, it does not go sideways, but it can run strait down hill. 

 
Title: Re: Building a 27'-0 GA
Post by: Scott L on August 01, 2021, 09:46:07 PM
It was a exciting day with the boat being turned over. It went well as the boat and everyone finished in one piece. I'll be happy to start the next stage of the build.
Title: Re: Building a 27'-0 GA
Post by: Rbob on August 01, 2021, 10:11:03 PM
Exciting day for sure, glad it went well and cant wait to see more.

Title: Re: Building a 27'-0 GA
Post by: json on August 01, 2021, 10:37:18 PM
Very cool! Nice work!
Title: Re: Building a 27'-0 GA
Post by: Todd j on August 01, 2021, 10:38:51 PM
Your kicking right along!   The next bit is a lot of fun
Title: Re: Building a 27'-0 GA
Post by: Scott L on August 02, 2021, 08:35:38 AM
Thanks for the good words. I am looking forward to building the top half.
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on August 02, 2021, 10:30:05 AM
Thanks for the good words. I am looking forward to building the top half.

In terms of man-hours, you're about 1/3rd done at this point :)

Title: Re: Building a 27'-0 GA
Post by: Grady300 on August 02, 2021, 05:18:54 PM
looking good keep it up you are moving right along
Title: Re: Building a 27'-0 GA
Post by: Rbob on August 02, 2021, 09:32:14 PM
Quite a system of you set up for the flip, you must have some experience in rigging.
Title: Re: Building a 27'-0 GA
Post by: Scott L on October 27, 2021, 09:54:46 PM
Well it has been a while I had some projects this summer as well as fishing but I'm back to work on the boat. started work on the cuddy.
Title: Re: Building a 27'-0 GA
Post by: Scott L on October 27, 2021, 10:00:07 PM
more pics
Title: Re: Building a 27'-0 GA
Post by: Rbob on October 27, 2021, 10:48:02 PM
Scott,

You have a diverse skill set and it shows, good on you!  I will keep an eye on your build and look forward to more pics / progress.

Title: Re: Building a 27'-0 GA
Post by: Todd j on October 28, 2021, 08:43:21 AM
It sure is fun to see a boat come together.  It’s looking gtreat!
Title: Re: Building a 27'-0 GA
Post by: ghelland on October 28, 2021, 07:04:56 PM
You and I are at the exact same place in our builds.  I am building insulation into the house on my boat and hope it does not add too much time.
Title: Re: Building a 27'-0 GA
Post by: Dan Boccia on October 29, 2021, 12:34:51 PM
Poking my nose in here, looks like a great build and some savvy folks paying attention! 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/ (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!
Title: Re: Building a 27'-0 GA
Post by: Scott L on October 29, 2021, 03:27:31 PM
Thanks Dan and every one else for the great feed back. As for the boat weight I went with Hydrotec plywood for the hull and boy is it heavy. I was looking for some weight in the hull but I am using Okuma for the rest to keep a little lighter up high. As far as engine choice I'm going with a 250. The fuel tank is being fabs right now and is 120 gals.
Title: Re: Building a 27'-0 GA
Post by: Todd j on October 29, 2021, 04:36:05 PM
It’s my opinion that the okume takes epoxy better than the hydrotech.  I like working with it.  Had I known this I would have used it for the sides of the boat too. 
Title: Re: Building a 27'-0 GA
Post by: Scott L on October 30, 2021, 08:14:31 AM
Yes I noticed the Hydrotec did not seem to soak up epoxy as well as other material but I don't have any concerns with it. I played with some strength test on some test pieces and I'm amazed on how strong the glass and epoxy is.
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon on October 30, 2021, 08:41:03 AM

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.
Title: Re: Building a 27'-0 GA
Post by: Scott L on November 03, 2021, 03:52:17 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
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon 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

Title: Re: Building a 27'-0 GA
Post by: Scott L on November 03, 2021, 06:25:15 PM
Thanks, no hurry .
Title: Re: Building a 27'-0 GA
Post by: Todd j on November 03, 2021, 11:11:13 PM
Scott, here is some food for thought. https://www.glacierboats.net/forum/index.php?topic=808.0
It should pretty much tell the tale.  Brian has threatened to sticky this iirc.  At a glance I think it looks like you have too much weight too far back if I’m reading it right.  HTH
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon 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 (https://www.glacierboats.net/forum/index.php?topic=808.0)) 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.

Title: Re: Building a 27'-0 GA
Post by: Scott L on November 04, 2021, 10:32:38 AM
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
Title: Re: Building a 27'-0 GA
Post by: Brian.Dixon 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.

Title: Re: Building a 27'-0 GA
Post by: Scott L on November 05, 2021, 09:06:45 AM
Brian, Here is what I came up with if you could take a look and see if it looks right. As far as outboard motors it should be around 700 lbs, I don't have any plans on using a bracket of any kind.