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I've received my CS23 plans and have been engrossed in them for the last couple of days

I'm planning to build the Open Deck version with a Closed Transom and just have a few questions regarding how I should read the plan.

1. In document B245/3_OV, Frame A2 doesn't list a measurement for the chine. I though perhaps it might translate from Frame A in the Regular (Long Deck) version, but as it sits in a different location, I don't think this is the case. Could you please tell me where I should be looking for that dimension?

2. Also on the same doc, Frame D seems to be misaligned to the BL?

3. For the Closed Transom, I'm looking at document B245/2_CT and I can see a Frame F which should be placed 149mm from the Transom but I don't think I should be removing Station F from the Regular plans as that would leave too great a distance between bulkheads? If I leave Station F in the original position, does it need to be converted to Frames and if so, Frames specific to the Open Deck version?

I've done a mock up of the Regular version and everything seems to line up, so my hopes are high I'm going to be able to achieve this



I know others have built the Closed Transom already so I'm sure it's just my understanding of the methodology that is holding me up. Any assistance you could provide would be greatly appreciated.

Cheers,
Reagen

Before we discuss each point, let's note that every version has exactly the same hull, the same shell. the decks are different and a few frames are different.
Because the hulls are identical, they are all built with molds based on the stations drawings. The plug is made from molds that use the stations drawing.
Later, we will drop frames in there that are slightly different and located in other places but use only the stations drawing to build the mold.

To the questions:
B245/3_OV, Frame A2 and A: I do not show the outside (perimeter) dimensions for the frames, only the inside parts. You should take the outside dimensions from the assembled hull. I could show them but after the fiberglassing, they will be different anyway. There is a small difference in location from the molds but since we do not use those frames to build the hull, it does not matter.
If you want, I will supply a station drawing for those two but, please, not use them for the molds and do not cut hem in advance, you would waste good plywood. With the slits for the flared bow and the fiberglass build up in the corners, my dimensions will not fit. Those dimensions are usefull for the nesting but when time comes to cut the frames, take the dimensions from the assembled hull.

Frame D misaligned: yes, the BL should be the lower face of the sole but on that drawing, no dimensions are taken from that BL. As for the other frames, those drawings show the inside cuts of the frames and those are taken from the proper line, they are correct. Thank you noticing that, I will slide the whole thing down a little bit, it is annoying.

Closed transom, frame F: there is an additional frame. You guessed correctly, the panel span would be too long without it. You add a frame behind F for that version but you do not remove the original, standard frame F, the one at 583 mm from the transom.
In other words, you have one more frame, behind F and the transom. I show the dimensions and location for that frame.
I should have named that additional frame F2.

Hi Jacques,

Thanks very much for getting back to me so quickly.

The plug is made from molds that use the stations drawing.
Later, we will drop frames in there that are slightly different and located in other places but use only the stations drawing to build the mold.

Got it, thanks! That does clear things up.

I was planning on using the marine ply to make up the molds and then cut down the frames from them once I do the flip. However "B245/3_OV, Frame A2 and A" are going to be larger than Frame 0 and Station A, due to being placed further back from the origin, so I guess those molds will have to be made from throw away material? Or would you recommend all molds be made from thow away material?

B245/3_OV, Frame A2 and A - If you want, I will supply a station drawing for those two

If it's not too much trouble, that would be great. It would be very useful as a starting point for cutting those frames and cross-referencing to the the actual hull dimensions, as well as nesting.

but, please, not use them for the molds and do not cut hem in advance

I wont

but you do not remove the original, standard frame F, the one at 583 mm from the transom.

Are there dimensions for converting Frame F (not F2) into an OV version, or should I plan to extrapolate that from the assembly once the deck, etc is in place?

Also, there seems to be a funny extra line on the top right of "E245/4 Station F". Is that anything to worry about? Is the camber of 79mm from the externals (1083mm), or off centred?



Again, thanks very much for your help. Really loving everything about this process (planning, support, community) so far. I'm sure my enthusiasm will drop some once I begin glass sanding

Cheers,
Reagen

Further to my questions above, I was reading the build notes and it says for the Transom on the "bracket version":

use 5 layers (of 1/2" plywood) for the transom, no clamping board.

However the Motorwell Side diagram on B245/2_CT, clearly shows a step where the clamping board would be.

Which way should I build it?

Edit: Would doing a full transom at 2 1/2" be enough reinforcement to allow installing a transom door?

Cheers
Reagen

Molds: I recommend throw away molds for all of them. It would be easier to stick to the standard method.

Now, you say that you will not use those 2 frames as molds. In that case, use the standard molds to take dimensions for the frames. With the fiberglass thickness added, they are very close to the frames shape. This was reported by a builder that did build two of those CS23's.

Are there dimensions for converting Frame F (not F2) into an OV version, or should I plan to extrapolate that from the assembly once the deck, etc is in place?

I don't understand that question, sorry. Do you plan to customize something?

The camber of F is an arc measured from the middle but, do not cut that camber on the mold unless you want to use it as a jig later when cutting the upper frames.

Transom thickness: 5 layers but some builders have used a 5 layers clamping board only to save plywood. Check the bolting pattern of you bracket and choose what you prefer.

Door: possible but will require braces on each side. Ideally, the opening should be above the level of the clamping board even if you do not use a clamping board.
You get that dimension from any of the transom drawings.

Thanks for you help so far Jacques.

The BOM for the CS23 lists some 9oz 4" woven tape but I cant see that specified anywhere on the lamination schedule.

Is that for splicing the larger panels?

Cheers,
Reagen

It is for what I call "cabinetry": the inside of boxes above deck. It gives a cleaner finish than biaxial.

Ok, thanks.

As to Frame F cut it out per Frame E. You may need to make a slight adjustment on the top edge as to the length of it to support the top deck.

Tom

Thanks Tom.

If I have another question relating to this build but targeting another area, can someone tell me if I should post that in this thread or open a new one?

I'll post it here and if I get it wrong I'll know for next time

---

I've got the bottom hull panels on and mostly they are aligning really well. There are a couple of spots near the bow where the panels are sitting off the station molds and stringers by quite a bit.

I'll let the pictures do the talking:

Stations Transom to C align really well, no concerns (see below).



Station B sits up a little, due to the hull curvature, which I suspect is to be expected (see below).



Station A also up a little but still to be expected (see below)?



My biggest concern is between Station B and A the hull panels are off the stringers by a lot (see below):



I suspect when it comes time to install them, I'll need to splice some more ply into them to fill this gap?

You are correct do not go by what the gaps are in the inside at this point, when you add the frame for the final time you will cut off the 3 points so that they fit better. You want the outside to have a fair and neat curvature at this point. Make it look pretty on the outside.

Tom

I've run into my next issue

I'm having trouble with getting the chine step right. The bow and stern section of the chine fit great but the middle section seems to be a different curve to the hull.

Stern section of the chine step:



Bow section of the chine step:



The middle section of the chine step:





I've checked twice against the plan and it does match up.



I can go and modify it to suit but I'm worried if I do that, I might run into problems down the road. I would prefer to know where I've gone wrong and try to rectify that.

The discrepancy is the same on the port and starboard side.

Could anyone suggest where I should be investigating to identify the cause?

Cheers.

I went ahead and cut a piece to fit and it looks a lot better now.



A few measurements along the curve were definitely different, perhaps that is just due to the unique shape the hull panels take when being bent into shape?

Hard to be sure, and you've already come up with a solution. It could be the hull panel is slightly off, but to me it looks like there's something slightly off about the curve of the chine strip at the gap; there's a nice curve leading in and out, but some waviness and a bit of a kink in that area . . or it could just be the photo. Build on!

Yeah, when I cut the second one I ignored one of the measurements (7,64) and focused more on letting the PVC pipe create the curve.

This meant the measurement I ignored was around 10mm "off" the curve I created, but it fit really well so I went with that.

What size radius should I be aiming for on the chine step and transom?

I've read it should be sharp but also believe a non radius bend weakens the glass?

I think you round it over to the correct radius, glass it, then built a sharp edge with filler. There are several topics on building sharp edges on the chine.

More experience builders will chime in with the correct radius and specifics.

It depends on what glass you're using, but 3/8" works for most cases, 1/2" is easier if your ply is thick enough to take it. Of course, sharpen it back up after the glass is done.

Is cool to see another one of these come together.

Specs call for 9mm or 12mm material for the hull?

Right now for glassing you need a 3/8"-1/2" curve on the edges for the 12oz fiberglass to take the curve. It will not take a sharp bend, so round any edges to 3/8" at this point. Then go back and make a sharp edge at the transom and on the sides where you will be on plane. Make a mix of epoxy, cabosil and wood flour, build a dam of cheap ply where you are building up the edge, tack it in place, and you will get a nice sharp edge. Hope I have been clear ask any questions if you have any. This is just for the where the side and transom meet the hull. The hull seams should be smooth, before taping.

Tom

Is it worthwhile fairing the "curviness" of the flare before the glass goes on?

I'm thinking by doing it that way, it will provide a tougher hull to have less fairing compound "outside" the glass.

You don't want any fairing compound underneath the glass, it would weaken the assembly. You could build up with epoxy and structural fillers, but that's going to be hard to sand.

Yes, no fairing, your next step would be to precoat the wood with a thin layer of epoxy so that it does not draw all of the epoxy from the fiberglass when you lay it down. Just go with what you have and then fair afterwards, for the easiest way to go.

Tom

I've got a question regarding the taping of the seams.

The plans I have say:

- Build the outside seams.
For this boat, we will build several longitudinal seams: keel, two seams at the chine step,
one long seam between the upper and lower topside and seams over the slits.
Do not aim for a complete lamination schedule right away. Build a single tape seam along
each seam including the bow and around transom, then check the hull and bottom for
fairness.

Is this saying there are two seams to tape at the chine, or the chine should have two layers of tape?

I found in another thread a builder who seems to have used 3 at the chine and keel?

I've just found my answer.



Is there any reason I couldn't do the following?



I had always planned to do an extra layer on the outer hull anyway. We have a lot of reef around my area and the extra layer would give me that little extra piece of mind

You don't ever tape on top of each tape; they are staggered.

Lay longest first in this scenario. If you have enough glass a 1" stagger is best.

Sure. The drawing was a rough approximation. I would ensure staggered joints as I progressed up through the layers.

How would you fair that hump?

How would you fair that hump?

Wouldn't the hump be greater with only 2 layers and the extra seams?

fallguy1000 wrote: ↑Sat Apr 30, 2022 8:01 am Lay longest first in this scenario. If you have enough glass a 1" stagger is best.

Do you mean option A over option B?


I've seen advocates for both and never really established an answer for which is best. My past glassing I've always done B.

B is incorrect unless you are fixing a hole or low area.

Here is all the rationale.

1. Laying longest first avoids potential air entrainment at overlap edges in b and poor bonds.

2. Sanding thru b can result in sanding the stagger off completely.

3. Strength in fiberglass is not achieved by shingling or effect of shingling. The strength in fiberglass happens with thickness. People generally get the intuition wrong here.

There are a few times other than hole repair where you may consider the other way..if, for example building up 3 layers allows the 3rd layer to go over a ridge or rise, anytime we end up fairer, we'd go shortest first, but then caution to fill the voids is important, etc.

Wow, that was fun. I got a and b confused in my reply and had to go back and fix it twice!

Thanks heaps for that info.

1. Laying longest first avoids potential air entrainment at overlap edges in b and poor bonds.

I've already noticed how hard it is to get the air out, so it makes a lot of sense.

OK, I thought I had my head around it but now I'm beginning to question myself.

If someone would be able to clarify if I've got this right, it would be greatly appreciated.

So going by this lamination schedule:



The completed outer layers would look like this?



Also, where it mentions:

A. Hull Bottom: 2 layers fabric, inside and out

I assume fabric means biaxial cloth (as that is all I have on the BOM)?

Yes, fabric and cloth are interchangeable here in the states. Also, I see three other problems. fallguy caught one, the second is you did not carry the first layer of fiberglass cloth up the side the 152mm and the third is on the chine you only have one of the tapes wrapping the corner, you need to change the second one so it has a short side on the bottom and a long side up the side. As it is providing no strength to join. Well I hope that helps you a bit. Feel free to ask questions.

Tom

Thanks Tom, I think I understand.

Is this more accurate?



(First layer of cloth would wrap 177mm up the side to ensure the 2 cloth layers are staggered)

It looks good. Tom

I've just realised why some of the fabric doesn't wrap (as per the lamination schedule by Jaques) - the fabric isn't wide enough.

If you draw what you have now, we can tell you how to get to finish. Overlaps are part of life in bigger boats.

It should all fit, if not you are making some of your overlaps to big. For example, in your last post you mentioned a 172mm overlap. Much to wide when a 148 would work just fine or 156. I did not realize that by going up that far you would not have any overlap on the other side.
Tom

This is what I ended up going with (just finished putting the last sheets on now) but would still love to hear your opinions.

My only comment is that overlaps can replace tapes, so a generalization here would be that you have too much tape/glass on the chines/keel.

If the overlaps are consistent enough, you could theoretically eliminate a tape for an overlap.

Obviously, this is a check with designer issue, but what happens is the heights get big when you tape and overlap same places.

When the stuff cures, take a straightedge from keel to chine at 90 or 45 aft toward bow and see the gap? That will be increased by so many laps on the chine.

Thanks fallguy.

When the stuff cures, take a straightedge from keel to chine at 90 or 45 aft toward bow and see the gap? That will be increased by so many laps on the chine.

I certainly do see the gap but I'm a little confused. Doesn't the lamination schedule specify a thickness of:

Chine:
- 2 layers biaxial tape each side, staggered 51mm = thickness of 2
- 2 layers fabric, offset edges = thickness of 4
Total thickness = 6 layers
Minus the 2 layers across the hull make for a differential of 4 layers

Keel:
- 3 layers each side, staggered = thickness of 3
- 2 layers fabric = thickness of 2
Total thickness = 5 layers
Minus the 2 layers across the hull make for a differential of 3 layers

I've put on:
Keel: 7 layers - 3 hull = differential 4 layers
Chine: 6 layers - 3 hull = differential 3 layers

So aren't I still in the same position as if I followed the lamination schedule?

(I've actually not put on the final hull layer yet so could I potentially lay that "within" the chines and keel, so still get the added thickness on the hull but not push up the seams?)

And I guess now, how can I address that gap?

The thing is that more overlaps in the same place raise up the seam.

So, your chine shows 7 layers of glass on the bottom edge, less 3 is a differential of 4.

4 layers thickness of db1200 is about 1/8"...

Had you moved the overlaps off the chine; you could have built two overlaps on the bottom; then the chine would have been 4 and the hull bottom 5...Or chine one overlap is 5 and 4 on hull bottom I like better, then you are fairing thickness of 0.030" versus 0.125".

As it is now, you will use more fairing compound, but you did ask for a critique.

what layer is not done? Can you move the overlap off the chine? I would. But if you only have the bottom panel done, not much you can chance cuz you need 2" overlap..unless say a 1.5" overlap gets you lower..

Sometimes things are counterintuitive. 7 layers of glass on the chine is not any better than 4-5..

Thanks fallguy.

The gap is around 3 mm at it's largest.



It's the final layer that isn't done.

I have 100 mm edge at chine and keel that I can overlap onto, is 50 mm enough overlap?



Or is it crucial that this layer also come 150 mm above the baseline? In that case I could do this:



Also, can I build up the gap with more cloth rather than compound (initially)?

Cloth is of little benefit. Once you get to the designer spec; adding cloth is adding weight and expense because fairing compounds are more solids than epoxy. And fiberglass is 1:1. So, adding glass is a bad idea unless it is in a place of certain benefit. A low spot on a keel, for example, could be glass because it'd be stronger than compound. But 3mm of glass and epoxy is a shit ton. You do not have to full fill that and you can fill each edge, but I'd find the angle that makes sense and full fill, personally.

50mm is the minimum overlap for structural elements.

The goal of ending and overlapping is first strength, but never forgetting to minimize fairing. This is why overlaps are often moved off the chines as I stated earlier.

Did you ever look for any hook? I usually ask the larger boat builders to watch out for it.

Did you ever look for any hook?

Yep, I've been on the lookout for hook and hog from day 1 and pleased to say there is none.

I have a few little areas with "blistering" beneath the glass.



Can anyone suggest a good way to deal with this?

The rest of the lamination looks good.

Those bubbles suck. They are caused by not enough work with a quality consolidation roller.

Any areas of air on the bottom and bottom edges to waterline need special attention because they can delam under extreme water pressure from waves and speed or both.

Any areas should be ground out and repaired or injected after drilling two holes with the perfect sized blunt needle.

You really want to address them as a matter of continuity. So, any place where delam can grow should be repaired well.

OK, I've sorted out all the bubbles and am ready to put on the skeg and strakes.

I'm wondering if there are alternatives to using timber for these parts? It would be great to have something a bit more durable.

I've seen one idea of making up a form and filling it with chopped glass and epoxy. This might be a little tricky on the curved parts of the hull.

Also there was a post from Jacques where he mentioned using "HD plastic (Aquaplas)". I've searched for Aquaplas but not found anything.

Is there another type of plastic which would bond well to the epoxy?

I personally think that a couple of layers of glass over wood would be absolutely fine.
Or you could do as I did and glue some UHMWPE strips to the hull. I have details on the prep work to glue that in my C17 thread.

I took a piece of 1 inch angle iron and used it as a mold. Wax it and level fill with epoxy and glass fibers. When you pull it from the mold and still green it is pretty flexible. You can bend it to shape and glue it to your hull.

rsiedl wrote: ↑Thu Aug 11, 2022 8:34 pm OK, I've sorted out all the bubbles and am ready to put on the skeg and strakes.
I'm wondering if there are alternatives to using timber for these parts? It would be great to have something a bit more durable.
I've seen one idea of making up a form and filling it with chopped glass and epoxy. This might be a little tricky on the curved parts of the hull.
Also there was a post from Jacques where he mentioned using "HD plastic (Aquaplas)". I've searched for Aquaplas but not found anything.
Is there another type of plastic which would bond well to the epoxy?

I made my stakes from 1.5" x 1.5" hoop pine, cut in two on the diagonal, glued and screwed onto the hull initially then screw removed and the holes filled with epoxy/woodflour. I then covered them with 2 x layers of 6" 6 oz biax 'tape'. 6 yrs later they are doing just fine! That said, I mostly operate over mud or sand, rarely stones, rocks or oyster beds.

Fuzz and Barraman's way are the easiest way to go. Round over the skeg and do as Barraman did also. Tom

Thanks for the advice on the strakes. I think I'll go down the path of milled glass/epoxy in some angle.

I am after some advice on mixing my own fairing compound.

Wood flour is hard to come by here so from my research I've settled on a mixture of Cabosil and Q-Cel 5020 (hollow sphere glass micro balloons).
https://www.cfsnet.co.uk/acatalog/Q-Cel_Range_TDS.pdf

The reading suggested a mix of 3:1 Cabosil to Q-Cel, so I made up a test piece to try it out. On the right was a mixture of Cabosil/Q-Cel and on the left was 100% Q-Cel.


Cabosil/Q-Cel


Q-Cel


Both held their shape during application but the Cabosil mixture "ran" after some time and flowed down.


The Q-Cel mixture stayed as it was applied.


I'm sure if I try and apply the Cabosil/Q-Cel mix to the hull it will just run out of the areas that need filling and make things worse.

The 100% Q-Cel mix would stay in the lows but it didn't have the smoothest of finishes.

Has anyone got any advice?

My questions:
- What consistency should the fairing compound be when applied?
- Should it the "run" afterwards, or hold the same shape as when it was applied?
- How thick should I be applying it?

Thanks in advance!

I mix 10 grams of cabosil and 40 grams of spheres..

Thanks fallguy.

Is it worth colouring it with anything?

Also, would the build up on the chine and transom (to get the sharper edge) be 100% cabosil?

rsiedl wrote: ↑Wed Aug 31, 2022 10:22 pm Thanks fallguy.

Is it worth colouring it with anything?

Not really. After awhile, I like to switch to Quikfair. It is pink and mixes up nice in small batches, but what I really like is that it fills cleaned pinholes well. To avoid lotsa pinholes; avoid too dry a mix. To avoid sag; avoid too wet. I pile the compound up and if it sags in 10 seconds on my hawk; it is too wet. Eventually, I had a formula. I can share it, but you'll need to tweak it for spheres and epoxy variation.

After you get lotsa colors; it gets too hard to see anything. This is why people do mist coats with spraypaint...to get uniform color to see sirface variation.

rsiedl wrote: ↑Wed Aug 31, 2022 10:24 pm Also, would the build up on the chine and transom (to get the sharper edge) be 100% cabosil?

I use cab and milled fiber. I rarely use fairing compound for edge buildup. It is a bit soft is all. If you have no milled fiber; you can use cab.

Make sure you round over the edges to at least 1/8" round so the paint will stick to the edges. Otherwise, the paint will come off over time there. Tom

Made up a test piece for my strakes.



I layed up some glass in a mold and gave it a coat of straight epoxy. Then filled that with epoxy/milled fibres and microspheres.

Will that do the job? My only concerns are the corner which is straight epoxy and the holes in the microsphere mix.

For the corner, perhaps I should lay down a bed of cabosil/epoxy first and embed the glass in that?

That will work fine as you will will be covering them with 12oz biax anyway. Tom

Bonding that to the hull will be the critical bit. All secondary bonds. So, you'll need 40 grit sanding on the hull side of the formed strake and something rough on the boat side, say 60 min. Then bonding them to the hull would be done by applying 1/16" vee trowel to both the strake and hull to avoid a dry joint. It'll be a bit tricky to hold the strakes on the hull and in position, but you can probably hot glue some blocks on and remove them with a bit of heat later.

Cross post with Tom. You can't laminate over them easily. More discussion needed.

The hot glue blocks will work. You need to come up with a way to put some weight on them while the epoxy glue sets. Just enough weight to ensure good contact.

You can hotglue small pieces of 3/4" by 3/4" pine and then put a piece across or make pieces with a dado for the strake, then a shim pushed gently would hold it.

There is no need to glass over these, but you can. But not the hull glass; that is too complex. To glass over these would require a light woven like 6 oz and then you need vacuum. I did this on the 13' Whaler and then cutout for the strake already there on a secons go for the whole hull. Bottom line is do not add these before hull glass or you are creating a nightmare and the hull will not be monocoque.

You made that sample in a mould off the boat, but you will build it in place, right?

I agree about the straight epoxy being too brittle to use for sharpening the edges, some milled fibers or structural filler added to the resin would be good.

pee wee wrote: ↑Wed Sep 07, 2022 9:40 am You made that sample in a mould off the boat, but you will build it in place, right?

I agree about the straight epoxy being too brittle to use for sharpening the edges, some milled fibers or structural filler added to the resin would be good.

He can mold that off the boat.

He doesn't need a sharp edge on his strakes, the shape he has now will work just fine, I don't know how much sharper you can get them and still cover with the fiberglass. If he wants to, he can add some cabosil or fiberglass fibers to the epoxy to strengthen it, but again they will be covered with fiberglass, and this is not a flats boat and will not be hitting anything where they are placed. Tom

Only covered with the glass from his mould...no hull glass on these!

Thanks for all your replies.

To clarify, I plan to make these up off the boat, epoxy glue them to the boat, then lay some glass over it (strips, not the full sheet glass that covers the hull panels - is that what you mean by "hull glass" fallguy?).

I'm also toying with the idea of making the form using glass, half filling with spheres/milled glass/epoxy, then flipping and using spheres/milled glass/epoxy to fill the rest and achieve a bond at the same time. Maybe a picture will explain that better:



Or perhaps spheres/milled glass/epoxy will not create a good bond and I'm better sticking to a cabosil/expoxy mix?

I don't like the proposed method because it will be hard to shape correct before applying it to the hull.

Just mould them and bond them, but the boat and part need to be scratched good, like I said.

And honestly, I see little reason to glass over them on the boat. You can and it is insirance, but to do it well is hard due to the shape.

Fairing compounds have lower shear ratings than cab and milled fiber. They sand away easy on purpose. This is easy to shape any errors, so I'd use cab.

I would not use glass spheres but use cabosil instead. I would also just build it in one piece and make sure your form is well lubricated, so it comes out easily. Unlike fallguy I recommend you fiberglass them on for easier fairing and better holding power at high speeds. I have been on here longer than fallguy and remember a commercial guide building 3 of these and he fiberglassed his down. Remember with a 250HP motor on this boat you will be reaching speeds in the high 40's to 50's with a lot of force on anything on the bottom. Tom

Don't care to argue. It will be hard to glass over the shape unless you have a 3/8" radius on top and fillet the sharp inside edge.

Even under vacuum, the bag will like to bridge the inside turn which would leave voids under the glass without a fillet, but would make the top turn.

See my pencil marks for the warnings is all. The top will be almost impossible to glass over no vac.

Again, fallguy that top edge can be rounded to 3/8 easily enough it is already 1//8. He can build the 3/8" rounding in his mold. Your rounding is 1/2" or more. Sorry to disagree. Tom

TomW1 wrote: ↑Thu Sep 08, 2022 9:22 pm Again, fallguy that top edge can be rounded to 3/8 easily enough it is already 1//8. He can build the 3/8" rounding in his mold. Your rounding is 1/2" or more. Sorry to disagree. Tom

We didn't disagree.

I drew a finger sketch and told him the 1/8" was too sharp! You are gauging my finger sketch as 1/2". Stop it!

Wood flour is hard to come by here so from my research I've settled on a mixture of Cabosil and Q-Cel 5020 (hollow sphere glass micro balloons).

You can buy a 9kg bag of 75 micron woodflour from Micromilling Pty Ltd for A$45 plus freight. It cost me A$115 to land a bag in Townsville - more than enough to complete my build.

Micromilling Pty Ltd
89 Cathcart St, Goulburn NSW 2580
sales@micromilling.com.au

I dealt with Danny Zylsra (02 48221886 danny@micromilling.com.au)

Q-Cel hollow spheres are mostly air, and therefore not suitable for anything structural. Intended for fairing only!

If you must have wide strakes rather than sharp ones like mine illustrated earlier, I would construct them directly on the hull as I did my reverse chines with a timber edge filled in with woodflour/epoxy, covered with 2 x staggered layers of 6oz biax tape.

Thanks for the info re wood flour barraman.

I'm now working on the layout for the strakes. Is there a preferred orientation for the strakes at the bow?

The other CS builds I've followed dont show much of an upturn at the bow, but every boat I've checked out near me has strakes coming up to the chine around the bow.

This one by Walkers Run:


This one by peter-curacao:


I've come up with this detail which seems ok for me, just want to make sure it wont cause any issues:




And last question, at the stern, should the strakes be parallel with the keel or slightly curved?

Seems that the desired function of the strakes determines how far forward they should run. I always assumed their purpose is to keep the boat from slipping from side to side, in which case they would offer little for effectiveness curving up the bow, and best to run parallel to the keel.

The curve up the bow is for elimination of any undesirable turbulence in higher seas, and looks nice.

You did not need to carry them all the way to the bow as the will be out of the water when on plane, but they look nice. As far as the transom it is best to end them 15-18" short of the transom, they have done their work and need that distance to let the water come back together for a smooth exit under the transom. The same with the skeg leave it short the same amount so you have smooth water flowing to the prop.

Tom

I'll start by saying that "I know nothing", but I have built a boat that works! If it were moi, I would do the strakes as per the pics of my boat on page 6 of this thread. That probably comes as no surprise!

I'd put one strake on each side - midway between the chine and the keel. I would taper it at the bow end and follow the sweep of the chine around to near the bow/cut water (or whatever the front of the boat is called! )
I would run the strake parallel to the keel from the widest part of the boat back to the transom.

If your putting twin motors on the boat then I would follow Tom's advice to stop the strakes short of the transom, but if your going with a single then I don't think it matters. You can see that mine run right to the transom.

By good luck more than anything (Jasques said my boat doesn't need strakes!) my boat handles very well in all the conditions I have had it out in, and it seems to have NO vices at all. It corners like its on rails! If I run it at say 30kts and pull it into a tight turn then feed all 250 hp into it, I can just get it to start to power-slide.

Your call on the skeg! I don't have one but maybe it may help give some protection if you are beaching it regularly or in danger of hitting shingle or oyster beds. I am usually over mud or sand!

Cheers
Lee

Lee the only thing I can reply to your response is remember you have the Mangusta with a much deeper/sharper keel than the CS23. Jacques talks about the skeg in the CS23 and the need for it in the study plans. Tom

TomW1 wrote: ↑Fri Sep 16, 2022 5:03 pm Lee the only thing I can reply to your response is remember you have the Mangusta with a much deeper/sharper keel than the CS23. Jacques talks about the skeg in the CS23 and the need for it in the study plans. Tom

The Mangusta has 18 degrees of deadrise at the transom, while the CS23 has ............................. 17 degrees!