Splash rail profile

[fallguy]

It can do if not positioned correctly.
Make sure you have a minimum 5 deg downward angle (-ve) from horizontal.
This will encourage the flow to be downward and not to attempt to stay attached and go around the rounded apex.

The down angle will be 13.4 degrees below horizontal, then the radius will be on the outer edge. I was hoping to prefinish it all; so if it fails; it would fail on the boat, so want to give it a a best try. As the video shows it is a Lot of water at times. The front of the boat has quite a bit going on. I won’t put anything on the bow extension because it sometimes dips into the oncoming wave, etc.

There is a lot of motion in the x plane, so I worry the boat velocity will push the water back and around the radius…

Maybe I ought to sharpen back the first 10 feet of all of them…this would reducc the fairing to half..

 

[Skip Johnson]

Yeah, but I gotta build like 160-200 feet of it..

If you're bagging the foam triangles on a table it's not that much hassle to line the glassed triangles along the edge of the table and butter and trowel goop along the edge of the table. with my 20' table I could do 160' in two or four days depending on set time of the mix and my speed assuming you have access to both sides of the table. In my case it'd be four days, I'm slowing down as I age ;-)

 

[Ad Hoc]

or simply over do the epoxy/resin at the apex...and then grind it sharp afterwards.

 

[fallguy]

or simply over do the epoxy/resin at the apex...and then grind it sharp afterwards.

Doesn’t really work that way under vac bag. In fact; to bag it well, the rail needs to be stood up off the table and then the edges trimmed. So, I might even skip bagging it and hand laminate. But the issue is the glass will not lay down well on the terminations.

Maybe I am just being lazy and need to build them and build back like Skip says.

I’m also going to build a glass knife at the bow..this might do a lot to keep the water from ever starting up the sides. The tricky area is the extension/hull junction.

 

[fallguy]

I zoomed in a drew a theoretical placement of the lower splashrail. I cannot run the splashrail all the way onto the extension.

Does this make sense as planned?

the waterline is the scumline

also, the leading edges of the bow extensions are built up with G10 fiberglass and pretty sharp .. a couple small dings from the 2000 mile river trip

 

[Ad Hoc]

....Does this make sense as planned?...

Should start at a positive distance above the resting DWL.

Otherwise it will be constantly grinding/graunching in waves, which creates noise and becomes a pain. ...

 

[fallguy]

Should start at a positive distance above the resting DWL.
View attachment 208593

Otherwise it will be constantly grinding/graunching in waves, which creates noise and becomes a pain. ...

Very much appreciate this comment as I was already planning it. It does change the notion of a 2nd rail as proposed by baeckmo as that panel will be maxed out at the top forward thus.

I am going to build a set of two more rails to have ready if the inside still has water run up. I think they will be shorter like 12’ long. I’ll only apply them if some water gets by.

I am also going to make two glass ‘knives’ 12” long for the lower part of the bow.

The bad bit is I cannot find anywhere to take the boat for the work and so have to try and work off my 1969 13’ Boston Whaler unless I can hang planks, but the boat is just not ideal for hanging plank as the top deck is not as wide as the hull and so would need to use top planking and it would get very complex…

 

[fallguy]

I started to build these and build constraints resulted in a bit smaller bond area. But I think it’ll be okay.

The squiggly line is the glass. The arrow is my oops. I didn’t think it mattered where I put the radius, but the saw is limited to tilt one way. I will have to fill that in after glassing.

The hull bond side is 2.25” long only; not 3”. The x direction is 2.075”. You can see the radius I made for glass wrap (as well as the errant ones). Sucks because I radiused 80 feet wrong.. Could have made the thing 3”, but wanted to yield 8 pieces from 24” panel. It was dumb because I have the materials on hand and sunk cost.

 

[BoatBuildLog]

Are you shaping the rail directly into the hull or planning to add it as a separate piece after the hull is finished ?

 

[fallguy]

Are you shaping the rail directly into the hull or planning to add it as a separate piece after the hull is finished ?

The hulls were done without a rail specified. So, I built the rails off the boat and will bond them on with 5200. The challenge is how to keep them in good contact with boat during the cure. Since the face of the rail is angled, screwing into the composite hull would be difficult. Bolting is relatively impossible as most of the back area is in watertight compartments.

Even the dry locating is difficult as they are 20 feet long. All suggestions are welcomed. The rails are made and ready for primer. Will add a pic now.

 

[fallguy]

About 2.25 back x 3.375 hypotenuse, bottom is like 2.5 or so, iirc.

Camera is fooling us a bit; the back is 90 degrees to the bottom. It will be like minus 13 degrees to water installed, iirc. The ends have a 45 to the back to avoid any water blasts from a direct hit. The thing has a light glass wrap over the exposed faces and a reinforced front edge for any small impacts.

Credit for this shape goes to @baeckmo and credit for location help to @Ad Hoc, these two men have really helped this boat go from epic failure to respectable on the water, although my vcg is perhaps a bit higher than it ought to be due to bdeck build weights and double bottom.

My current plan is to shape locate the thing with masking tape; also difficult because I want to tape on my antifouling paint and it may lift some on removal. Then I was going to spot hotglue foam blocks to the hull and mask at the top. Then perhaps apply adhesive like 5200 and spot bond a shaped block. Or perhaps a combination of that and some screws for my sanity; although would prefer not to punch thru the hull. At 3” above dwl and angled up at the front, I won’t always have tabbing behind, so risk delam when screwing. I expect a drilled hole will reduce that, but the screws would pull easily.

It is pretty hot here in Texas (upper 80s and low 90s here on coast and I have been a bit off and just starting to think bp meds may be the cause, so been avoiding the heat and napping and seeing doc today. Maybe I can paint next week.

Again, ideas welcome. Ratchet straps are not gonna work; just too much grease on the part and would result in uneven bonding.

Truth told, these belonged on the hull design.

 

[montero]

I would glue the aluminum profile , angle bar and not mess with the foam.

 

[montero]

What I still find problematic is the lack of trimming options. Therefore, I might want to make an adjustable rail for testing purposes, which might be difficult to do, but not impossible.
in addition, there may be a segmented rail with sections at different heights, at different angles or with different curvature on individual sections.

 

[fallguy]

What I still find problematic is the lack of trimming options. Therefore, I might want to make an adjustable rail for testing purposes, which might be difficult to do, but not impossible.
in addition, there may be a segmented rail with sections at different heights, at different angles or with different curvature on individual sections.

The video does a good job of showing where the rail is needed and a seasoned NA advised a correction to the original plan.

There is no temporary attachment method that can withstand the forces at play here.

Furthermore, boats have splashrails and they all follow the same general locating.

These choices are further limited by the hard chine on the panel at dwl.

The only question for me is after install and a good cure period to see if the bow extensions need sharpening, but they seem good except for a log or lock ding on the tip of one.

 

[montero]

I can't find the thread about when you converted your Skoota into a sidewalled hovercraft .Deck wave slamming plate.