Skegs
tahalsted
Jan 1, 2021 #28320

So, after deciding NOT to get blown down to Locust beach today, I stole another Larry B idea, and cobbled together a skeg for both of my boats. At roughly 9“ long, and 1-1/2” high (that was the size of my available plexiglass scraps), I Christie-Taped them below the cockpit (butt-pit) of each boat. The plexiglass strips are semi-stabilized by 1/2“ plastic quarter-round molding.

I'm curious about where other folks have tried mounting skegs to their surfskis, and how they've behaved (the skegs/boats, not the paddlers).
Especially in my old Evo, I am very interested in reducing the amount of long axis rotation, in the hopes that I can also stop swimming as often, and have a more-controlled, more relaxed ride. I think the V8 doesn't really need it, but I want to see how it feels with one.

On a side note, I kinda wished I'd gone out around 9 or 10am, when the wind was steadier. At 12:30 or so, I kept getting salt spray in the face (up on shore) from the 60mph gusts, and watched the tops blow off for quite a ways. Several of us kept saying “hey, it's flattened out - we can do this”, followed by “holy crap - where did that come from”.

I'll see what tomorrow is like.

Duncan Howat
Jan 1 #28321

Look out tomorrow afternoon. Also while your all warm and toasty huddled over the heat vent, to night, read Rufus's The Weather Cafe, for the next 20 days of weather coming at us. I find him quite accurate on longer range stuff. May need to take up trail running —in Airzona. Snow guy

Reivers Dustin
Jan 1 #28322

Hope LB sees this. We were talking this week about placement. He's trying things … doing the whole mad scientist with skegs.

David Scherrer
Jan 1 #28324

Tom
my unsolicited suggestion is to get more stuff out of the water…I did find when I was beginning to race in S.F.Bay, that attaching via Velcro, a standard 4lb. Divers weight to the lowest part of the bilge really helped in the stability department…
The more rudder or skeg the greater the resistance. Try dragging a pencil through the water. Fairly convincing.
D

tahalsted
Jan 1 #28325

Well this proof of concept skeg is just taped on, so removal is also an option - when I'm more of a stable guy. Maybe I should try velcro or some sort of track so that I could slide it back and forth

Larry Bussinger
Jan 2 #28327

The rudder should be as close under the paddler as possible, but the retractable one and taped on one were behind because that’s either where they would fit or stay out of the way when carrying the boat. I don’t like your ½ “ quarter molding as I think its too much resistance, I glued the skeg (2-1/2” x 12” x 2 mm) to a 1” wide by 2mm thick strap and used double stick tape to hold it down. Covered with Gorilla tape. Its not going anywhere. A 1-1/2” high skeg probably isn’t high enough. The resistance to roll is there, but rather subtle, like adding an inch to the width of the boat. It slows the roll and gives you a split second longer to react. I have found that it also helps to prevent the boat from getting blown off when going upwind. It also helps in the turns going downwind as the boat will tend to rotate around the skeg. Really haven’t found any disadvantage to having it there. Other than image.

In response to David, I don’t feel any drag as my skeg is only 2 mm wide (a thick postcard) whereas I can feel the drag of my drain scupper.

tahalsted

Jan 2 #28332

Thanks, Larry - I'll try out what I have so far, to see what it does. If it really feels like it helps, I can redo it wider, and maybe lose the 1/2” “berms”.
I would've been happy with 1/4“ stock, but went with what was available and cheap. Maybe a nice little 1/4” cove mold - tapered at the leading and trailing edges to reduce drag (as these are) will be my next test.

And it might be time to get a bandsaw. My chop saw and bench grinder/sander are a bit cumbersome for this level of tweak-work

tahalsted
Jan 2 #28333

The Weather Cafe is a great site! Thanks, Duncan

Tyler Irwin
Jan 2 #28338

Why don’t you guys just try mounting a mini foil? It’ll at least provide a tiny bit of lift and add the vertical stability that you’re talking about.

gsouthstone

Jan 2 #28342

Tom;
The rotomolded Edge 15 has two opposing fins positioned just aft of the bucket, images. The boat response was immediate when leaning hard on the rail and doing a hard “white-water” brace. I typically paddled the boats “bare” without any rudder or fins. I figured the fins cost about 10% hull speed at least. I surfed this boat model in the Caribbean and found the fins re-assuring when caught offshore in monster trade winds and reef breaks. The positioning of the fins reminds me of the stabilizer fins found on ferries and cruise ships. I hope that helps.

Side note; After a fluke wind gust took and split my new Nelo open on the big Birch tree at the MP beach edge this week- look for embedded green colored chips- I'm about ready to go back to a rotomolded ski.
Gary

tahalsted

Jan 2 #28345

They look like oddly placed orca pectoral fins!

But I do understand the concept. One of my earlier thoughts was to try a pair of smaller ones like yours (or more elongated, like my current ones), in the vicinity of the cockpit. Who knows what other nautical nuttiness will spring forth during the pandemic? Maybe a bow-bulb…

David Scherrer
Jan 3 #28346

Ha! Bow bulbs have been tried on racing canoes, back in the 70s ( lots of things were tried in the 70s) somehow just wasn’t worth it….A real weed collector as you can imagine!
D

gsouthstone
Jan 3 #28348

I once experimented with taping skegs in various numbers and locations on waveskis'. I I ran a small string to each of the taped on fins to the cockpit, I got tired of fabricating them. Acrylic works, but it also slices the birthday suit effectively. I ended up thermoforming polystyrene into a “T”, the rounded edge usually only left a bruise.
G

Nicholas Cryder

Jan 6 #28364

When I was new to surfski I did some experiments with a custom ski I made (18' x 19“, very similar to a V8Pro), and used a deep tuttle box (wind surf / sup use this for fins). It worked really well, but required a fin of at least 5” to be noticeable… which was a LOT of drag in a craft that was fundamentally meant to be highly responsive and low drag (fast). The skeg also reduced the turning response of the ski considerably. In the end I found that the rudder does the exact same thing but with the benefit of directional force to make up for the added drag.

That said, a skeg is a crutch. If there is a balance issue, the skeg is just masking it. I stopped using a pure surf rudder for all but the biggest winter days in the Bay because I wanted to improve my downwind skills, and I knew the big rudder was masking some mistakes I was making (turning too often which was blunting my ability to over-glide waves and link runs). Going to a smaller rudder, weedless rudder forced me to improve my balance and anticipation skills. It's worked, and has translated to being typically :15 to 30 seconds / KM faster. That is usually four to five minutes faster on a Wildcat to Squalicum Beach run. I recently made a post on Surfski.info about improving balance through good footwork, it's linked here. (includes ten tips to improve balance). There is a follow up post on the next page that clarifies some other commenter's questions as well.

Cheers,

Cryder

tahalsted
Jan 10 #28384

I finally got my Evo on the water with the new skeg and a surf rudder, to see how they performed.
Nicholas and David - you were spot-on – ANYTHING added to the hull just slowed me down, and it felt like I was dragging a keg of cheap beer behind me.

I switched back to the smaller rudder, and tried again – still slow.
I pulled off the skeg, and voila - another mph with much less drag.

And after an eerily foggy start, it cleared off, to a beautiful, sunny paddle.

So, no skegs for me.
And I appear to be fine with the smaller rudder on that boat.
For the bigger bay stuff, I'll probably just stick with my V8, for now…

Cheers!