Can we get some really basic basics?

[JaredD]

I feel like the boat talk around here becomes a second language that I don’t fully comprehend. It may be a limited group that needs it… but it would be great if we could get some definitions and context around some of the nomenclature and acronyms that y’all boat building geniuses know like I know finance (my area of specialty).
I know I could Google, ask ChatGPT, or ask ForaFrank- but would rather hear it from experts who can add the context.
I would imagine I am not alone.

Some examples:
Deadrise- I kinda get it, but not really
0 degree vs 12 degree
The “pad”
Vacuum Bagging vs cold molding

And maybe even some silly things like splash rails (do they actually help?!?)

I really want to do a @Chris_Morejohn build but feel like I know how to run boats and fish off them, but have no idea of the basics to know ‘what’ to build.

[Birdyshooter]

I try my best to get out of acronym hell. I’m a govt employee…. that’s all we talk. Wife is pharma… more of the same. I equate it to the kids saying lol, wtf, brb, or whatever they say these days. If you have questions, we’ll respond in proper English as best we can. Fire away!!

[coconutgroves]

Easiest way to view deadrise is to get behind the the back of a boat and face the stern.

From the drain hole (center line, or center keel), draw a straight horizontal line outward to the side of the boat (port or starboard). If the bottom of the boat is flat, and imaginary line going outward stays flat, that is a 0 degree deadrise.

A 12 degree would have an angle slightly rising higher to the water line at the side of the boat.

Some people mix up dead rise is measured from, which confuses things. I won’t confuse that here.

One other factor is that poling skiffs have a V hull at the bow and taper to a flatter bottom mid-ship, with some keeping an angle like the 12 degree, or going near flat like the 2 degree.

The benefit of a low deadrise is poling super skinny. The drawback is getting beat up in chop. Higher deadrise handles waves and chop much better. That’s why bigger water skiffs typically are 12 dergree, while the super skinny, lagoon, back country boats are 2 degree.

[PanaceaFlats]

I learned something today. I can confidently say now that my skiff has zero dead rise. Maybe even some negative dead rise in places.

[PanaceaFlats]

Based on the collection of talent here. Just post your question. Almost certain you’ll get your answer with a healthy dose of context

[MikeCockman]

It’s like getting into fly fishing..lol.. Gurglers, Maribou, Saddle hackle, roll cast, ect..

Deadrise is essentially the V at the stern.

Stern is the back of the boat.

Transom is also the back of the boat but where the motor mounts.

Sole is the floor/boat bottom sorta. Gets misused a lot, and can change with the type of vessel.

Decks are elevated floors.

Freeboard is the height of the sides of the hull.

Spray rails are extensions from the hull above the waterline, under the rub rail, to deflect water. Yes they work

Sheer is a bit more difficult to explain.

Keel is the center line of hull bottom

Strakes are the 1/2 circle shaped things either side of the keel

Chines are the outer edge of the hull bottom

Gunwales (gunnels) are top side and generally extend deck to deck along both sides of the boat.

Bulkheads connect the decks to the sole, or hull.

Vacuum bagging is just that. In its simplest form, you lay the glass out dry. Encase it in a bag. Apply a vacuum to it to remove all air and moisture. Then you “inject” the resin into it. This does several things. One being the proper amount of resin is used. To much resin, especially polyester can become brittle, not enough and the glass isn’t fully saturated. Excess resin is also excess weight. The pressure involved is kinda mind boggling, even though it doesn’t seem like it.

Laminating is basically glueing.

Hand lay up is laying fiberglass by hand.

And it goes on..

[StSpartina]

Very informative , thanks.
Funny, I thought hand lay ment something else

[Zika]

Some excellent definitions already shared. You also mentioned pad. It is a hull design element amidships to stern that allows more speed and performance. Pads or flattened sections of the keel are most commonly used in bass boats with lots of horsepower to get up on the surface and scoot.

There is also notched or pocket transoms and tunnel hulls. The former are smaller indentations on the aft centerline that serve to funnel water up to the engine’s lower unit. Tunnels are typically longer and more pronounced to also allow water re-direction and shallow operation. As @Smackdaddy53, @coconutgroves, @hipshot and others will tell you, a combination of tunnel, jack plate, compression plate, low water pick-up systems and a cupped prop allow the engine to be raised up to run as shallow as possible without hitting the skeg and sea bottom.

[coconutgroves]

That negative dead rise you mention could be hook. But hook can run aft to bow and also keel to side. It is typically at the stern and the theory is it helps with planing. It’s is pretty uncommon on shallow skiffs.

[MaverickMA]

I learned a few things based on a post about a Blackjack from @TidewateR - Tumblehome - very simply, tumblehome is when a hull curves inward above the waterline. If you look at a black jack, or @Zika’s macroskiff pic, both boats hulls cure inward towards the stern. Older sailing ships also had this design element - originally done for stability, it is a very attractive element, especially when combined with bow flare like both boats mentioned above.

[PanaceaFlats]

The Negative dead rise was meant to be funny. But you bring up a good point with Hook.
During the construction I built in a slight hook unknowingly. Unfortunately its hooking more like a dolphin
With all its faults, she has been a wonderful learning project and I thoroughly enjoy every minute on the water with her. Basically, for those dreaming of a build regardless of skill,

Just get out there and start. You wont regret it.

[Brandon-Beers]

Cold mold: boats build around stations, typically used in custom sport fish boats, but not always. Basically profile shapes are laid up upside down and then the boat is built upside down. This is a one at a time Boat building method. This is typically what you’ll see with the home builders building CMJ boats.

Gunnel: I typically use this term as the area on the inside of a boat below the top cap to the floor, where you would see rods horizontally mounted. But some people refer to it as in walking the gunnel so more of the top cap in my opinion.

Three part boat construction vs 2 part boat construction. When building fiberglass boats in molds a three part boat would be the hull, liner and top cap.
Two part would be the hull and then a top cap that is also the liner. My personal preference is for three part boat Construction verse two part. Two part is a cheaper faster way of building a boat and provides less access to rigging later.

Pre-peg: not really used in what we’re doing, but more used to for Formula One and high-end sailboat racing and rockets, fishing rod blanks and golf clubs etc. This is when carbon fiber is already infused with epoxy and then is laid into a mold, vacuum bagged or shrink wrapped, and then put into an autoclave. This is the best and most expensive way of making carbon fiber parts, but it is typically reserved for corporations with deep pockets and fancy equipment.

Sheer: let’s describe this as the shape of the boat from the rub-rail.

[MaverickMA]

Okay - this is getting funny. Everyone on here has avoided explaining sheer in detail. I saw reference to “sheer lines” in the same post about that Blackjack and looked it up right after I looked up “Tumblehome” - the internet wasn’t very clear about it either.

Is it sheer coincidence that nobody can explain sheer? Or are we sheering the knowers from the ignoramousi based on their understanding of sheer? Personally, I’m sheerly confused, but it was described as the profile of a hull - though it was unclear on whether from a side view, bow view, stern view, or any view.

Sheerly, someone on here can explain . . .

[Zika]

@boothboatworks might be able to shed some light on sheer.

[boothboatworks]

Sheer is just a measure of deck curvature in the longitudinal (bow to stern) direction. It’s best observed when looking at the profile (side) view of a boat. It can also be viewed in the body plan but that’s not the best place to view it.

The below deck barge has no sheer.

This deck barge has forward sheer.

[boothboatworks]

I put a red line on the sheer of this 256 blackjack

[MaverickMA]

Great explanation, @boothboatworks - really appreciate it!

[lemaymiami]

Here’s one more element that probably confuses folks. Hard chine vs soft chine. This is the shape of where the bottom of a boat meets the sides. Hard chines are in general dryer running than soft (rounded) chines -but the soft or round chine hulls while being much “wetter” when running are much quieter when poling. As always everything in boat design are trade-offs (you get this feature while giving up or minimizing that feature..). Old time hulls like the original Challengers had very soft chines and were quite wet riding as a result. That lead old timers to add spray rails to compensate for the tendency… Nowadays spray rails have migrated to the top edge of the gunnels on some very high end skiffs as a result of wanting the silent poling while not ending up with a skiff where you needed a full rainsuit if there was any chop on the water’s surface…
“Aren’t boats fun?”

[JaredD]

Wow, this has turned out to be MUCH more informative than I was even hoping for.

Sheer makes sense now as well.

Thank you for all the great information and clarification.

I hope others benefit as much as I have.

[MaverickMA]

@JaredD - I know I have. Would be very cool if @boothboatworks and @Chris_Morejohn and any others involved in boat design would be willing to keep this going with other misunderstood concepts as they think of them.