Outdoor build of GA Kodiak, Orange, CA

[Todd j]

It’s not cast iron yet.  Yes it would be for the flip. I might get a pile of 6x6x1/2  Ibeam. It’s way overkill,  it it’s free to me.... maybe. This stuff is 25# per foot and my shop is 20 feet wide.  I don’t trust the structure to hold the the beam.  If I did I would use it to flip the hull.  If your Interested read my “a house for a GA “ thread here.  It chronicles my dogshit to honey boat shed Reno/build.   

[json]

It’s not cast iron yet.  Yes it would be for the flip. I might get a pile of 6x6x1/2  Ibeam. It’s way overkill,  it it’s free to me.... maybe. This stuff is 25# per foot and my shop is 20 feet wide.  I don’t trust the structure to hold the the beam.  If I did I would use it to flip the hull.  If your Interested read my “a house for a GA “ thread here.  It chronicles my dogshit to honey boat shed Reno/build.   

Right, ya, I read that towards the end of when you were doing it. Now that I remember you also have those canted beams too, so ya, attaching a 500lb beam to those guys doesn't sound very safe haha. I was going to use my cranes that I built to do my flip but then realized that my hull won't fit under them on it's side. So 10 dudes + pizza and beer sounds like it's going to be the way for me.

[json]

Brian, quick question about fairing the bottom and chine Seam with the transom (pre-glass). Should I try my best to keep that edge as sharp as possible? I was reading somewhere (maybe on fishyfish) that if you don’t have a sharp exit of your bottom assembly you will lose lift and possibly not be able to get on plane. I doubt such an extreme scenario would happen from rounding the edge some but what should I be aiming for for a radius between the aft end of the bottom and chines to the transom?

[Todd j]

There was a ton of discussion on this subject not long ago on fishy fish.  From what I remember.  Radius the transom for glass and make the edge sharp.  Sounds like it makes a big difference. 

[json]

Cool cool... thx Todd.

[Brian.Dixon]

If you want a sharp stern transition (bottom to transom corner), you'd do it last.  Radius as necessary for the glass to make the bend OK, scrape and fair all overlapped glass in prep for final epoxy coats.  THEN you can form a sharper edge with thickened epoxy ... it'll take a few passes and you'll want to use a metal ruler or other straight edge to verify that the new 'edge' prescribes a straight run off the bottom of the boat.  Fill defects, repeat.  The corner doesn't need to be razor sharp .. a small radius is fine.  Some think it improves efficiency ... and it may when on smooth water (lake or similar), but offshore it won't make a measurable difference.  Some say it'll help the boat get on plane ... but unless you've hugely rounded that corner (!!), it won't help on a Great Alaskan .. the GA only raises it's bow by about 4 degrees and then it lifts onto plane like an elevator ... and the bow-up trim reduces once on plane ... finally reducing to just over 2 degrees when at speeds around 40 knots and faster.

Bottom line: Sharpen up the corner if it makes you feel better, but in a practical world, this would be more an a 'polishing the apple' exercise than anything.  If it were me and mid-winter, waiting for Spring, then maybe I'd do it.  But if the calendar is zooming by and another boating season approaches then I'd skip it and go boating ... and decide later on if I felt it was still worth it to me or not (I suspect not).  Oh .. one other thing.  The sharper edge may allow the boat to go a couple knots faster, say, having top speed of 42-43 knots instead of 40 knots.  Previous experience with one other GA (slightly stern heavy) says the boat picks up a slight porpoising above 40-42 knots or so ... that's FAST!  The sharp edge may let you go a little faster without any instabilities showing up.

Brian

[Jim_Hbar]

My 2 cents worth.

I suspect that once the hull has passed the speed where the flow separates cleanly at the stern and the chines, the stern/transom radius has virtually zero effect - all other things being equal.  However, the sharper the edge, the slower the speed possible before the boundary layer turns the corner and re-attaches to the stern, and the hull stops planing.

But the chines (at the rear of the boat) need to be equally as "sharp" as the stern.  Sharpening the stern won't be as effective if the water climbs the sides and attaches to the sides of the hull.

The lighter the bottom loading, the more effective the sharpening will be.

[json]

Interesting, ok, thanks guys. I am not going to worry about it right now then. Going to focus on getting the glass to follow the edge and lay flat.

[Brian.Dixon]

Good point on the chines.  Curves that cause the water to want to 'climb up' cause an equal and opposite reaction .. the hull is slightly pulled down.  That's a loss in efficiency.  But ... it's very small on a boat this size and undetectable in normal use.  I'd consider doing it mostly because it would make me feel more like I did the very best job I could in building the boat.  Race boats that need to eek out that list .5 mph is where you usually see these 'sharp edge' efforts being used.

bd

[json]

Sand fill sand sand fill sand sand glass fill sand... I was working on taping the chines yesterday and was breaking into a new roll of 10oz that I had bought online (maybe on ebay, can't remember). Anyways, as soon as I opened it I knew something was off. It was stiff as if if had already been wet out with resin (although it hadn't been). I went ahead and rolled up 3 meters of it and cut some tape out of it for the chines, and got busy doing a wet on wet biax+10oz layup. About 2 feet into it I had to abandon the 10oz because it wouldn't wet out or lay flat on the seams. Has anyone run into fabric like this? Is it just cheap crappy fabric or is there some other underlying problem that it was subject to (age, moisture, ??)?

I have a deadline to flip by August 30 (or one of my limited helpers won't be available for the next 2 months), so hoping to put it in overdrive and get there. Back to sand sand fill sand glass fill sand...

[Brian.Dixon]

Do you have some other 10-oz cloth to compare to?  There is a type of cloth called "finishing cloth" that has finer yarn and a tight weave .... it's designed to lay flat and have a smooth texture that is easy to finish to a smooth surface (that means "might be done after just one fill coat").  What I do *NOT* like about finishing cloth is that it won't follow a bend (like on a seam) very well and if you dare wrinkle it, the wrinkly shows through the finish later ... tough to get flat and must be faired out with a fairing mix.  Now, if you're just glassing a large flat surface such as the decks in the boat, or the interior surface of hull panels, before installation, then the stuff works fine.  You might save it for that kind of work, but normal woven fiberglass will be a lot nicer to work with on those hard corners. 

Now ... since you likely have biax curing away right now and didn't get to use woven glass on top of it, wet on wet, you likely will have hard ridges (the knitting that holds the two layers of glass together in the biax) to fair in.  The quickest way to get rid of the knitting on biax is to scrape it off with a good (Sandvik or similar) carbide scraper ... the knitting is not structural.  Scrape it off, add a fill coat, then put your next layer of glass right on it.

Brian

PS: If you lose the 2 months this Fall, choose to be OK with that ... something about trying to get in a hurry invokes Murphy's Law and mucho paino.... relax and give the boat your best, and be OK with losing a couple of months or go find another handy helper to help you turn over the hull (or be creative with chain hoists as many others have done).

[davidnolan]

Going to follow this more closely.  My buddy with a 28 Novi is going to pull the twin 200 Suzis off of it and wants a 30 ft by 9.5 Kodiak next spring.         Nice pics.    Dave Nolan

[json]

Do you have some other 10-oz cloth to compare to?  There is a type of cloth called "finishing cloth" that has finer yarn and a tight weave .... it's designed to lay flat and have a smooth texture that is easy to finish to a smooth surface (that means "might be done after just one fill coat").  What I do *NOT* like about finishing cloth is that it won't follow a bend (like on a seam) very well and if you dare wrinkle it, the wrinkly shows through the finish later ... tough to get flat and must be faired out with a fairing mix.  Now, if you're just glassing a large flat surface such as the decks in the boat, or the interior surface of hull panels, before installation, then the stuff works fine.  You might save it for that kind of work, but normal woven fiberglass will be a lot nicer to work with on those hard corners. 

Now ... since you likely have biax curing away right now and didn't get to use woven glass on top of it, wet on wet, you likely will have hard ridges (the knitting that holds the two layers of glass together in the biax) to fair in.  The quickest way to get rid of the knitting on biax is to scrape it off with a good (Sandvik or similar) carbide scraper ... the knitting is not structural.  Scrape it off, add a fill coat, then put your next layer of glass right on it.

Brian

PS: If you lose the 2 months this Fall, choose to be OK with that ... something about trying to get in a hurry invokes Murphy's Law and mucho paino.... relax and give the boat your best, and be OK with losing a couple of months or go find another handy helper to help you turn over the hull (or be creative with chain hoists as many others have done).

I went and posted a chargeback for it this morning, it was billed as #7500 style, and is very rigid vs some other #7500 I have laying around. The weave looks the same (from what I saw yesterday), it's just weirdly stiff and plasticky.

That's a good point about Murphy's law. I really want to launch on my 40th birthday (next May) but it's probably a good idea to put workmanship first and make sure this is a safe vessel for my family and others to be riding in. Point well received. 

[Brian.Dixon]

That's odd about the glass.  It's probably been treated with a wetting agent designed for a particular type of resin ... and not the standard product and/or treatment.

You can launch by then, no problem.  Just bring oars.... 

Brian

[Todd j]

Fiberglasssupply.com look on the net or call.  I often get stuff the next day.  Been  great to deal with so far.  I talk to Rich.