The 18 Foot SeaSled

Regarding your last photo above; have you considered bullnosing that leading edge of the foredeck?
I looked on the plans, it doesn't show the thickness you have.
Building it up and fairing it round would allow it to take layers of e-glass.

I'm intrigued to see where and how the 3/8 strips are going to run.

Oh, and did you get all your deadline work done by May 1st?

 

The foredeck is two 3/8” sheets so approx 3/4” thickness. I assumed that I would eventually cover that with a rub rail.I agree it looks rough. However whatever the planking it’ll be faired and covered with 1708. I’ll probably use a combination of strips and templates.

yes I finally did get my non-boat work done.

might also be my camera angles using a very wide angle lens… but the stem plate is 3/8 plywood with the deck stringers in between (beveled) and the deck is another piece of 3/8” plywood on top of that. I had to study it closely but the tunnel is a very twisty v shaped affair.

 

You should call a surveyor and explain that you are doing a home build and see if he/she would take on a contract when you are complete. The reason being is that your bank/insurance company will more than likely want to know that the construction meets accepted build standards. When completely enclosed, it is will be difficult to confirm the construction.
Often, though normally larger boats, the surveyor will want to have a look at a few points in the construction. They put their reputation on the line when they survey a boat and will want to be confident that what they might not see when everything is closed in is adequate. Additionally they assume liability for some accuracy in the
survey exposing themselves to litigation though most surveys that I have had done preface the survey with so many waivers and notes to limitation, that you really wonder what you are getting

ABYC puts out a very comprehensive manual for small vessels. While expensive, following their guidelines will ensure that your boat will actually pass a survey. If the cost is uncomfortable,
you can sometimes find the information on line as sections sometimes appear on the internet. Following these guidelines also produces a safer boat. The manual is well worth the dollars and when your boat is complete, you could easily sell it to another first time boat builder. Wiring, venting, fuel tank design and installation etc are covered. If you install your fuel tank incorrectly, and have the surveyor reject or make note on the survey, the cost of making things conform might be many times the cost of the manual.

A comment wrt to your comment above "I would like them to be molded into the sides or bottom of the boat"
I am assuming that you are NOT intending for the outer skin of the fuel tank will be the actual bottom of the boat. If memory serves me correctly, only a diesel tank can use the outer hull structure for the sides of a tank.
If the tank is metal, you need to ensure that any (rain/bilge) water cannot pool around a fuel tank. Mentioned only because you should have some air space around the boat. Any connections, valves, sending units have to be accessible for inspection and repair.
On this form, you can probably find some relatively indepth discussion on tank mounting. Especially aluminum tank mounting

You might pass over these experienced words from Fallguy especially the part "too much weight forward"
We mounted our fuel tanks on our 21 foot jet boats against the transom. 21 feet, monohull, 80 inch chine width, 12 degree deadrise, 1100 pounds of engine/ jet pretty much at the back of the boat, no cabin. The boats ran about 4 -5 degrees nose up attitude and except for one (an 18 foot got squirrely at +55 mph) we never installed a jetovator to trim the boat)


While there have been comments about ensuring that the fuel tanks are behind the center of gravity there is a bit more to deal with. At rest, any boat ( displacement or planing)
the center of gravity (COG) coincides with the center of buoyancy (COB) but a planing hull (COB)/Center of Lift changes as the boat increases speed and with speed the
wetted surface moves rearwards and the center of lift, ie higher dynamic forces, also moves rearward. Too much weight forward then can cause the nose to come down.
(causing porpoising or a fast dangerous bow drop) For a short boat such as yours, I think that your tanks in the location shown in your sketch are too far forward. Is that a heavy a/c unit that you are also installing forward?


I also see in your drawing some foam floatation meaning that you are intending to "float your boat". |I expect that you have done the weight calculations to ensure that the foam will in
fact accomplish this. An outboard boat less than about 20 feet, ( not counting the length from the outboard and over 2 hp) requires foam to provide level and upright floatation which takes us back to the first
suggestion in this post, you should contact a surveyor as they want to ensure that there is adequate floatation to meet Coast Guard/ABYC recommendations.

I imagine that you have read Dog Calvary's thread. He has been fighting aerated water with a single outboard. It will be interesting to see how your boat is affected in this configuration.

 

For a mostly wood boat; the use of foam ought to be calculated because the need should be fairly low. Perhaps a bit aft near the engines.

Weight forward challenges must not be overlooked. Yes, you have a lot of buoyancy. No, you do not want to put the CoG forward of the CoB, or you'll end up in negative trim, like me, and the boat will sneeze always, etc.

I found and retained a surveyor early as Barry mentioned, so I was able to consult a bit on a few items.. The reason I ask is because the surveyor will basically decide whether to approve of disapprove of your fuel tanks, based on their interpretation of US rules. Modern requirements are for diurnal tanks and a charcoal canister. Consider this early warning a gift from me.. If your surveyor doesn't approve of the tank system; you'll have to redo it all. I don't believe I would approve of a homemade tank for simple liability. Rules vary per country and interpretation varies per surveyor. @gonzo , I believe is still surveying in the US; perhaps he can expound on fuel tanks..., especially homemade ones

Electrical systems and battery business are also especially critical.

 

Agreed but there are two elements, one enough foam to keep the boat afloat and the other is upright and level floatation. ( including a portion of the passengers weight)
I suspect but am not a naval architect that there must be a way of ensuring the upright and level floatation, or maybe surveyors just ignore it. Barring filling the boat with water,
it would be difficult to ensure upright and level.

I would expect, and hope that an NA responds, that if the boats design info (data) was available that calculations would ensure level and upright.

 

One note that I missed previously unless it has been covered on earlier posts
Most states require a boat license (numbers on the boat) . You should check as to the process before you get too far along. There may be a "Home Built" category or even an "Experimental" category that can make the application for you boat license a little easier

 

Yes I have the paperwork and a binder of all my build receipts which is what they ask for. And probably more photos than is reasonable.

 

Kind of a slow go especially around the curve of the stem assembly. The plan is to keep trimming the 3/8" plywood strips and attach them with thickened epoxy. I've done plenty of tongue and groove and I think while this might be ideal for caravel-planked boats without fiberglass, I will be sanding and fairing the surface so I think that it's probably not worth the effort. epoxy between the strips will be quite strong. I am using 404 filler and priming the strips with un-thicken-ed epoxy. I am also clamping the centerline keelson to the strips to keep them fairly fair. I initially made a mistake in clamping the first strip to the large piece of plywood on the bottom and that made it look really bad so I may just have to sand it down and make some small filler strips in this area but have never done this before. I think it is improving with each lamination. I was initially using a few 18ga pin nails to hold things together till the epoxy kicked but ill be pulling those out soon. I have been able to avoid any sort of nails and keep with just the clamps which is what I prefer.

I attached a drawing of the way it will be finished in my head. Before the overall fiberglass work.

 

Well maybe not the super fast progress that I would’ve liked… but I think that I’ve got a system going that is going to produce the profile that I want. This is mostly an update post.
On this photo you can see the non-tripping chine line on the outside. The Fiberglass will wrap to the hull here.

 

Glued up another two strips today. Pretty close to being able to template. Template will let me put up bigger chunks of plywood, and speed construction.



Starting to be able to see the tunnel. If only epoxy didn’t need half a day to setup enough to remove clamps… one can dream.

 

Well, I made it far enough that I could template and do some plywood bending. Which might be kind of like spoon bending… i.e. entirely in your head and largely mythical. Albeit with some clever clamping I was able to template and epoxy up a big chunk.

Pretty decent progress for a Saturday. Nice to stress test that freshly epoxied plywood with the screw clamping… ☠️

 

Not sure why you are using epoxy for those bonds. Titebond 3 will glue up in about 30-60 minutes. That all requires sheathing anyway..

 

“Titebond III Ultimate Wood Glue is not for continuous submersion or for use below the waterline. Not for structural or load bearing applications. “

I use it extensively when doing cabinetry but compared to the amount of epoxy used laminating it’s pretty minimal. 2 pumps of west system for about every 1.5 linear feet.

I’m maybe saving 200$ on glue joints hardly worthwhile.

 

It isn't the money, but the time. All of that is under lots of sheathing..otherwise, you could pin it all with finish nails and keep on truckin..

 

yeah, some of the less onerous ones I used some 18 gauge nails, I did pull them out once the epoxy set.
however, the side joints are structural, and or the fiberglass skins are supported by the plywood. I do agree it would save time, lots of twist so needed clamps. Nails wouldn’t have held broke a few cheap screws…



The front of the SeaSled is arguably the worst, and most difficult part of the planking to do.

and who wants all that inbeded iron screwing with their compass? (Humor)


viewing from inside the bow facing port bulkhead to left bow to right.
tabbing the planking to the stem assembly (keel / keelson) the other side along the center line will take some filler and creativity.