LB26

Power Boats only. Please include the boat type in your question.
jacquesmm
Site Admin
Site Admin
Posts: 28215
Joined: Wed Aug 14, 2002 1:00 am
Location: Florida USA
Contact:

Re: LB26

Post by jacquesmm »

les2021 wrote: Fri Aug 20, 2021 10:21 am Afternoon Guys

Question for Jacques

1. Is it possible to move Frame D 300mm to the aft to make the cabin slightly larger ? Or is this structurally positioned.
I'll reply before Monday. I just came back from a trip.

2. Do I need to put any high density inserts in the hull for pipe exits, air intake, exhaust etc.
Yes, always. I will comment later.
Jacques Mertens - Designer
http://boatbuildercentral.com

fallguy1000
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 10198
Joined: Tue Jan 12, 2010 12:25 am

Re: LB26

Post by fallguy1000 »

Just so you know Les, you can always insert thickened resins in place of low density core, if needed.

It is never as nice and does not compensate for an entire section.

The hull to deck joint can also be made with hd and even the hull bottom to hull side (hull side, first portion can be made with hd). This is to take load impacts from bottom when wave jumping which you probably will largely avoid.

I tried to plan all my hardware. Unfortunately, I failed to account for tow hooks on the bow or transom. Got lucky on the transom.

Almost impossible to account for everything for the designer. And I just want to point that out for your benefit Les. Something like hawse pipe is rarely spec'd.

On my build, recently, I painted the helm riser. No idea why, but all my cabosil fills grew when the boat got heated to above 100F. Be warned.

Best of luck. And I waited for JM to respond.
My boat build is here -------->

viewtopic.php?f=12&t=62495

jacquesmm
Site Admin
Site Admin
Posts: 28215
Joined: Wed Aug 14, 2002 1:00 am
Location: Florida USA
Contact:

Re: LB26

Post by jacquesmm »

1. Move frame D : The part below the sole (= floor frame) must stay but you can move the upper frame. It is tricky, you will have a weird step going down in the cabin.
Jacques Mertens - Designer
http://boatbuildercentral.com

jacquesmm
Site Admin
Site Admin
Posts: 28215
Joined: Wed Aug 14, 2002 1:00 am
Location: Florida USA
Contact:

Re: LB26

Post by jacquesmm »

2. Yes, inserts or as Fallguy writes, a transition to a thick single skin.
Look at this page:
https://www.amateurboatbuilding.com/art ... h/jig.html
Image

I wrote that article years ago, the pictures is from an old Airex manual. I show the transition for a keel but you can use the same principle.
It's single skin or HD foam or a filler made from resin and milled fibers.

I had a dry exhaust made that way and it never burned but for the exhaust, I prefer a fiber insert.
Jacques Mertens - Designer
http://boatbuildercentral.com

fallguy1000
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 10198
Joined: Tue Jan 12, 2010 12:25 am

Re: LB26

Post by fallguy1000 »

Another thing to be careful of with thickened resins is post cure change.

Solids change at different rates under heat.

Les-I put each hull of my boat in a shipping container and cooked it for 8 hours to get 150F average for two hours and cool down two hours.

You don't have toi get as fancy, but you can heat the boat up to 110F for a day prior to fairing, but after any thickened inserts are done to avoid experiencing print through and post fairing post paint changes.

Another trick that can be used in foam is you can purposely step the inserts proud of the hull. I did not, but this is valuable for finding them later if you expect they can get lost. Glass must be considered if so and transistion is not a step, of course, but a ramp. Preglassing may also be needed.

The post cure strengthens most epoxies.

I did not post cure my helm riser and it hit 110 in the tent last week and some filled screw holes expanded permanently in the finish. Oh well. But just letting you know it can happen. Using some milled fiber in holes may help the issue; not sure..
My boat build is here -------->

viewtopic.php?f=12&t=62495

les2021
Active Poster
Active Poster
Posts: 229
Joined: Fri Mar 05, 2021 8:21 am
Location: Crete, Greece

Re: LB26

Post by les2021 »

Hi Dan / Jacques

Not sure I put the question over very well.

I have used Corecell M200 on the full length of the keel and chine, 300mm so I think I am ok here. I have also constructed the transom in M200, once again I think that will be fine for exhaust etc.
It is really things like air intake location, head tank pump out point. cooling water intake.

Dan your method is fibres and resin which sounds fine, can I use a straight M200 inserts ?

Jacques regarding moving frame D, I will draw it up and see if is worth the move. Cheers for having a look though.

Final day of fairing tomorrow.... and yes I will be pleased !!! Hope to get the skin coat of glass on this weekend.

Once again thanks for the input Dan. ( by the way my workshop is over a 100 degrees every day at the moment , it's killing me) Keep the beer coming....

Les

fallguy1000
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 10198
Joined: Tue Jan 12, 2010 12:25 am

Re: LB26

Post by fallguy1000 »

For things like the pumpout and water fill and the $700 worth of required electrical connections, I did nothing. The electrical had their own gaskets and I simply cut holes into regulat core.

For deck fills, if you bed them in butyl, they should be fine over regular core as long as you don't go crazy on torque.

The m200 is fine. I prefer aquaplas for screw holding.

I planned all cleat locations on the Skoota, but botched on the bow eye. The cleats have hardfills and all will have backers. I read somewhere each cleat should be backed to support a minimum of half the boat, and I did some calcs and decided on 24 inch square backing minimums which takes my 10,000 pound design to 416 pounds per inch (too high, but what I am using). I have plywood decks in place for two of them, hindsight would have been M200 as one locker filled with water last year and the ply swelled post finish and cause some issues and broke the laminate in one spot. That locker simply did not have a drain installed and we got hammered with rains last August.

Here is the electrical and water. The stuff is on the foam just above a plywood core which we did because the ply gets narrow at the beam..

There is extra glass here and I got lucky because only on raw core, but because on extra glass (this is a chine), nothing is needed. The vent hole is bedded on a big black rubber washer.

If you end up over 4-5# core, and you are worried; decore 2-3x the bolt sizes and refill with milled fiber and epoxy and cabosil and bed in butyl. Limit is about 3/4" hole or it'll heat up and crack on you.

You can always, as a matter of last resort, build an M200 block and make it proud of the hull. I am doing this option for a camera mounting base on the cabin roof. Not done yet.
676E7F37-4DFD-4173-B874-D474656CBFBB.jpeg
Rubrails are simply screwed onto raw core every 6". I am nervous about them failing and I bolted them on where I could access behind and bedded/sealed in 4000//4200/5200.

Those hull windows, only bedded in butyl. I did not even decore the raw edge. If I see any issues, I will take them out and chop out the edges and fill with thixo. Top windows are bedded with sase neoprene foam, no core modification, in corecell either pvc or m80. Under the middle window up/escape hatch, there is a diesel heating system fill and vent, also raw core, bedded in butyl, just screws in core where there was extra glass. No access behind it to do much..
59EEA6D2-4779-4F55-AFEE-9894A4D8D705.jpeg
My boat build is here -------->

viewtopic.php?f=12&t=62495

les2021
Active Poster
Active Poster
Posts: 229
Joined: Fri Mar 05, 2021 8:21 am
Location: Crete, Greece

Re: LB26

Post by les2021 »

Cheers Dan

I feel happy now, that all makes sense. Boat building is new to me but asking questions is always the right way. No doubt there will be a lot more.

The hull is going well, I am taking the approach the better I can get the foam core the easier the glassing will be and the fairing. The lines are looking good.

All the best .

Les

les2021
Active Poster
Active Poster
Posts: 229
Joined: Fri Mar 05, 2021 8:21 am
Location: Crete, Greece

Re: LB26

Post by les2021 »

Afternoon All

I think I have finished fairing the hull prior to laminating. I will attach some photos, if anyone has any comments please let me know.
I have tried to get the hull as near as perfect as I can so as to save masses of after laminating fairing. There are a couple of areas I will just fill a little but basically I think I am there..... Unless someone tells me different !!!! Also will re mark the DWL.
1EA913A5-03E7-4703-BA54-79835E60229C.jpeg
Fibreglass ready to go.....

Cheers

Les
Attachments
8BA7C01F-B9FD-4DF2-B8E2-07715DCE1600.jpeg
A52D2E58-0B9A-4045-AC6B-0A6D4E562B82.jpeg

fallguy1000
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 10198
Joined: Tue Jan 12, 2010 12:25 am

Re: LB26

Post by fallguy1000 »

Looks ready, but make sire you have no sharp edges.

After you glass, you want the transom to exit cleanly with a sharp edge and I sort of believe in a sharp bottom chine edge as well.

Make sure you are pretty roughly sanded. Most studies are for 40-60 grit, any higher and you risk delamination. If you went to say 120, go over it again with 40-60.

Also, make sure the surface is super clean, sanding dirt also is a terrible bond surface.

Forgive me if this is all no brainer advice.
My boat build is here -------->

viewtopic.php?f=12&t=62495

Post Reply

Who is online

Users browsing this forum: Amazon [Bot] and 13 guests