Sea Sled madness. It’s in my brain.

Thanks DogCavalry.

I'm unable to figure out how to message someone. Maybe it's because I'm new and only have 4 posts?

Do you think the claim of 120 hours build time on the TX sled is reasonable? Seems crazy low to me.

 

Select inbox at the top. You can start there. Or select their name, similar process. But you may be too new.

 

If you are already quite skillful, 120 is doable.

 

Cool. I wonder if the TX-18 stitch and glue design could be modified back to the original higher gunwale height?

I'm not qualified to do that but easier is always better for me as I tend to make things harder than they need to be.

I guess I need to buy a set of plans and look at them first.

Do you have a build thread I can look at DogCavalry?

 

Just this one. I took what I needed from the tx18 plans. No more. The set comes with panel layout for a taller, narrower sea sled if that's what you want.

 

Taller is what I want - and maximum beam which is 8'+/- here.

I really didn't want to build but it looks like I may have to as I hate center consoles and every cat hull is at a premium price point. Any that I can find would need to have the console removed and the cockpit reworked for a standard helm or a dual console. There are almost no small cats anyway - plenty of 22' and up which are way too heavy for me.

I've used a 2000 model 18' McKee Craft dual console for ten years and it's getting too heavy for me to launch and recover (3000 lbs. +/- at least partially waterlogged) in my old age, is a wet ride and pounds my passengers to death in snotty seas (the helm has a suspension seat). I mainly run 20-40 miles offshore to fish. I already have a single 2000 model Johnson Ocean Pro 150 that has been a wonderful workhorse, all of the accoutrements (bait tanks, hatches, fish box, seats, 80 gallon fuel tank, rails, cleats, windscreen, folding ladder, VHF, chartplotter, GPS controlled trolling motor, etc.) from the old McKee Craft. She will live on her trailer under a metal carport.

I thought I needed a cat but it looks like a sled may be easier to build and handle the short wave period 2'-6' very steep chop we get every day in the Gulf of Mexico even better. Is that also your opinion?

Off to read 200 pages. Be back shortly.

 

@Geno67 the Thread Sea Sled Information is very informative, and less about me being a doofus.

 

Whew. That took a while. You need a thingie on the stern bottom. I saw one in a study plan for a cat. Hold on a minute and I'll find it again.

No worries. You're far from a dufus my friend. You make my head hurt with calculations that are correct. She's built and in the water and earning her keep.

This is from Glen L Marine Auqacat build notes (it has a very low hull at the back to compress the foam to reduce pounding in much the same way as the sled). Look all the way to the bottom. This is for an 18' or 5.5 meter so would need to be scaled up proportionately of course.

Knock one together from 3 pieces of scrap lumber and glue it in place. If it works, make another one just like it, add three coats of epoxy and glass it in place.

 

Well now. That's very interesting.

 

Everyone that built a cat with a single on their forum had to use one to stop cavitation and they all said it works a treat. You see the same thing on many of the fiberglass cats of later models with singles.

 

It wouldn't let me edit a pic in my last post without a url. You can see it from the stern on this one.

Also - I hit ten posts and now "start a conversation" shows under your name when I click it. Looks like you need ten to message here.

 

So there seems to be two approaches to managing the water against leg:

1 Sharpen the front of the outboard with a fairing, of aluminum plate or wood/epoxy with a horizontal component across the top to stop water blasting up the front of the engine.
2 direct the water around the leg with a wedge or half arrowhead or ramp.

I can see advantages and disadvantages to both, and both have been suggested by folks with vastly greater knowledge and experience (and probably intelligence) than me. I can make a list of attributes but not assign relative weight to them.

Adding plate to the front of the leg increases steering forces and side load on the leg.
Vs
Adding something to the hull. That will possibly reduce steering response a little.

The space between the leg and the transom is pretty limited. I can't get much "axe head" in there. Something on the hull underside can do a better job in that regard.

 

If you can accept adding a small wedge to the hull, it is preferable "flow-wise". Questions are, how do you fit it safely, and how deep is necessary to have its bottom level with the underside of the AV plate? This is the solution I've used both for cats and inverted-vee's, but in those cases the center-line level has been above the keels, så no problems with beaching or "parking on the dry".

 

I don't think beaching Serenity is likely. The aft cross beam on our grid is at about 4', 1.2m so as long as the wedge is shorter than that, it's fine.

From a drag perspective, it seems like the elongated tetrahedron should be best.

 

That's why we take independent quantitative data.
Without which, it falls into subjectivity..and once in that realm...ugh, even God has an answer for you!!