The 18 Foot SeaSled

[DogCavalry]

Well, my results aren't worth much yet. I need a leg extension, and to clean the bottom of a hundred pounds of barnacles and muscles.
But yesterday I was out at about 7000#, planing.

 

[Darkzillicon]

Well, my results aren't worth much yet. I need a leg extension, and to clean the bottom of a hundred pounds of barnacles and muscles.
But yesterday I was out at about 7000#, planing.

I can understand that my sea-ray had a full carpet on the bottom when I left her in the water for 9 months. Little barnacles tunneled into the underwater lights. You might consider epoxying copper sheet metal to the bottom lol.

that’s pretty impressive, based on my numbers if I turn my sled into a bathtub it’ll displace 6000 pounds of water roughly.

 

[DogCavalry]

No, bottom paint is commonly available here. But where I live we have a tidal grid, so the intent was to regularly clean her bottom. But a neighbor broke the grid by being... not smart. And low enough tide only comes at midnight this time of year.

 

[Darkzillicon]

No, bottom paint is commonly available here. But where I live we have a tidal grid, so the intent was to regularly clean her bottom. But a neighbor broke the grid by being... not smart. And low enough tide only comes at midnight this time of year.

I will admit to being completely clueless about marine growth in those northern climates however, down here in Florida if you don’t have bottom paint, you will very quickly be covered in green slime within a few days. Monthly hull scraping is the norm. At least for my big girl, this sea sled will probably be a trailer queen.

 

[fallguy]

do you think I should give up on the alternating layers and just make it a thicker Coosa board and then do my lamination entirely on the outside or do you like the idea of the alternating sandwich?

A friend of mine in Alaska knew these guys who did a transom repair. The boat broke open and everyone perished. Most likely they failed to tab the transom layers into the hull well enough.

The way the transom on this boat is designed gives me major pause because you cannot tab glass to the hull around the 1x4s.

My friend and I both tend to be willing to throw the red flag, but we are both not comfortable providing laminate schedules. Someone inevitably will do poor work or poor tabbing back into the hull and end up at the bottom.

My boat has a much narrower hull, a slightly poorer core of 1.5" and was built with 4 layers of db1700 on each side with overwraps over the top to 8 layers and wraps to the hull of 10,8,6,4 all around, inside and out.

So, you need to exceed that for a wider transom.

But I really am not qualified to do more than get off the boat before it leaves the dock if I don't like the way it is built.

Since the construction method here is not monocoque; I am even less suited to tell you how to build it.

Someone here may jump all over me for this is pof vs monocoque and core, but the mix and match of coosa and pof is the hesitation for me..

Basically, you have a light glue bond holding the transom on.

 

[fallguy]

You really probably need to stop. What was the original power plant on the as drawn boat?

Not to alarm you, but the transom needs some planning before you start working on gunwhales.

It is sort of the most important structural element and you are underthinking it.

 

[Darkzillicon]

You really probably need to stop. What was the original power plant on the as drawn boat?

Not to alarm you, but the transom needs some planning before you start working on gunwhales.

It is sort of the most important structural element and you are underthinking it.

There is probably quite a bit of wisdom in what you’re saying however, I was planning on tabbing the transom into the rest of the boat. I’ll make a drawing so you can see.

Also, the original boat was entirely spec to handle a 90 hp outboard and was simply screwed plywood no fiberglass whatsoever. However, I’m not the designer, so maybe he was incompetent.

again I’ll make the drawing and we can revisit.

 

[DogCavalry]

@Darkzillicon you should invest in the TX18 plans from bateau.com You are building a different sea sled, but the TX18 plans include professional scantlings and layup schedule for an 18' sea sled. Just for that, definitely worth the money. Costs less than half filling Serenity's fuel tank. I bought them to see how they ( and Jackson in 1954) handled non tripping chines. Worth every penny. And I may well build one some day.

 

[Darkzillicon]

@fallguy

I considered tabbing in the transom to go naturally with glassing it in. However I have additional stringers to add that I needed to get in place before fiberglass could go in. I Imagined in my head this sort of arrangement. Transom is also tabbed to the hull on the outside as well.

also I got the impression from this that coosa was comparable to the Douglas fir marine ply I am using. https://www.thehulltruth.com/boatin...-plywood-test-added-marine-grade-plywood.html

 

[Darkzillicon]

@Darkzillicon you should invest in the TX18 plans from bateau.com You are building a different sea sled, but the TX18 plans include professional scantlings and layup schedule for an 18' sea sled. Just for that, definitely worth the money. Costs less than half filling Serenity's fuel tank. I bought them to see how they ( and Jackson in 1954) handled non tripping chines. Worth every penny. And I may well build one some day.

I tend to think I’m using the Jackson design but I haven’t found a definitive answer on the source of my plans other than it was in boatbuilder magazine. But I’ll definitely look into acquiring a copy. I looked at their boat design on the website as well as yours, and they’re both a bit more slab sided however, the twin keels on mine are just as straight.

 

[fallguy]

That looks like some of the most difficult hodge podge of glasswork I have ever seen.

I think @Rumars may have some knowledge of pof construction, but you wouldn't be starting off with 1/2" coosa and then building the internals to it unless you intend to layer on all the other ?
I'm too confused to add much value. You need more wisdom than I can offer here. Sorry.

 

[Darkzillicon]

Got it thanks.

 

[fallguy]

In general, I think you ought to hold off until you get a few more contributors to comment. This is an international forum, so contributors come from both sides of the time zones and guys have free time variables, so be patient.

 

[Darkzillicon]

I'll share the updated drawings once they are complete.

 

[Ad Hoc]

It looks like, on the face of it at least, you are missing some important structural elements, noted here in black:

These of course would be tailored to the number of and size of O/B eng you are having too.
Because you need to stiffen up the transom and also the top edge that supports the verticals too.