LB26

Power Boats only. Please include the boat type in your question.
Fuzz
* Bateau Builder - Expert *
* Bateau Builder - Expert *
Posts: 8920
Joined: Tue Aug 02, 2011 4:23 am
Location: Kasilof, Alaska

Re: LB26

Post by Fuzz »

That looks like a very good and clean install of all the running gear.
About the fuel tanks have you looked into building them out of fiberglass? Folks around here have been building their diesel tanks with glass for the past 30-40 years.

CNYBoater
Frequent Poster
Frequent Poster
Posts: 31
Joined: Fri May 27, 2022 12:43 pm
Location: Oswego County, NY

Re: LB26

Post by CNYBoater »

That is some beautiful running gear. Enjoying your thread, and good job.

Cbuf
Active Poster
Active Poster
Posts: 356
Joined: Sat Mar 30, 2019 10:38 pm
Location: Wisconsin

Re: LB26

Post by Cbuf »

very nice. I would check the forums on if your rudder is long enough. I remember somebody had an issue of the rudder being to short and that the prop shaft was propelling water on only half of the rudder which caused steering issues.

Nice work. I only mention this as I remember somebody posted a pic that extended the prop shaft through the rudder and it only covered 40-50 percent of the rudder and the fix was to lengthen. BTW I know every little about inbounds, just mentioning it.

cbuf
See my LM 18 build here.
viewtopic.php?t=64254
See my LM 18 Questions here.
viewtopic.php?f=2&t=64299&hilit=lm18\
Finished Boat Here
viewtopic.php?f=25&t=65173

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

Re: LB26

Post by fallguy1000 »

No comments on the other forum, yet, but international forum and mid week, people are busy.

Here is what I would foam. Do a calc and see how much you get. For the sides, use some polystyrene and go up say 18". Use a can of spray foam to glue it in and then pour the pour foam after the 'wall' is made. The amount of foam should be enough for the mass of the engine. Your boat would never sink this way, even if water filled it at the dock. And in a catastrophic event, like a broken sea cock, the water will stop filling the boat at about the area of the midpoint of the motor.

If 18" is way too much foam in the calculation, then you can isolate and air chamber the bigger chambers down below. Use a piece of corecell or a couple offcuts and glass it in on the top and used thickened epoxy. You may need to hotglue some supports in so the pieces don't fall in, but a well sealed air chamber is just as good as the foam. The sole is not a sufficient seal. I can see where I set my soles in nice beds of thickened epoxy and there are air voids. An airtight chamber can be made, but with intent.

The calc should be easy. Just determine how many cubic inches or cubic meters you have. If you don't want to buy foam, you can use all chambers, but all sealed with db400 minimum, plus sole.

5C0C5E0A-0851-47EF-9214-E65C88E7B5D8.jpeg
My boat build is here -------->

viewtopic.php?f=12&t=62495

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

Re: LB26

Post by fallguy1000 »

E5793151-186A-4EAC-A876-709DACA30144.jpeg
You can also use this to advantage Les.

The airtight or buoyancy chambers tops can make a sole for a side locker. A rope locker, for example would be one nice idea. I don't know if you have enough room, but fenders are always a pain to find homes for..and it looks like you might have storage enough for 4 of them back there. You could make say a 2-6" lip up above the watertight top and leave a drainhole for some nice wet lockers..that are not real wet, but you leave them open for the fender lines to dry out. Buy the fenders now, so you can design for them.

The hullsides are rather narrow, so taking the chambers up and creating a locker base higher is really top shelf construction.
My boat build is here -------->

viewtopic.php?f=12&t=62495

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 consider is sound. Buoyancy foam can also make the boat quieter. So, if you foam the hull sides say up a foot, all the water noise on the hull will be deadened.

I figure you need about 11 cubic feet of foam. See what happens if you foam up 12" all the way around the sides and down to the hull, how many cuft you get...
My boat build is here -------->

viewtopic.php?f=12&t=62495

TomW1
Very Active Poster
Very Active Poster
Posts: 5844
Joined: Sun Apr 19, 2015 10:57 pm
Location: Bryson City, NC

Re: LB26

Post by TomW1 »

fallguy I am going to disagree the whole hull is made of foam and i would not like the looks of extra added foam on the inside of the hull. Well, that are my thoughts and as Jacques does not recommend any added foam for this boat. Boats over 23' do not require additional flotational foam per the USCG and ABYC.
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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

Re: LB26

Post by fallguy1000 »

TomW1 wrote: Sun Nov 13, 2022 4:42 pm fallguy I am going to disagree the whole hull is made of foam and i would not like the looks of extra added foam on the inside of the hull. Well, that are my thoughts and as Jacques does not recommend any added foam for this boat. Boats over 23' do not require additional flotational foam per the USCG and ABYC.
Disagree substantively then.

This was all covered awhile back. The extra foam is all hidden. The requirements for ABYC do not matter for a private builder who wants a safe boat. This boat would sink beneath the engine before it stops as is.
My boat build is here -------->

viewtopic.php?f=12&t=62495

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

Re: LB26

Post by fallguy1000 »

Each square foot (not cubic foot) of a typical 4# per cubic foot foam with 1708 laminated on each side weights 1/12th of a cubic foot or about 0.333 pounds or core, plus 100 ounces per yard or 100/9 ounces of glass and resin per yard as hand laid. Or 11 ounces plus 4 ounces or roughly one pound of weight. And that amount of foam is about 1/12th of a cubic foot or 64 pounds/12 or about 5.3 pounds of buoyancy. Or, the net is about 4 pounds for each square foot of hull, net.

So, for LB26...

About 8' behind the engine by 8m wide, bottom gives about 64x4 or 256 pounds.

Sides about 8x3x2 or 48x4 or 192 pounds

Transom about 8x3 or 24x4 or 96 pounds

Stringers are offset by lotsa tabbing and thicker bottom.

Area behind engine offers about 550 pounds. Engine and gear is about 800. Earlier, I suggested about 500 pounds of buoyancy foam. I stand by it.
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 Guys

Apologise for not responding sooner, power cuts and no internet ( joys of living on a small island ! )

Cheers Fuzz / CNYBoater / Cbuf Have at last sorted the tank issue, the main problem is getting a certified tank to pass the end survey. Anyway I found a really great company in Holland, they have made the plastic tank all certified and tested and it is on it's way to me as we speak. I have decided that the 3 tanks as per the drawing is so expensive and difficult to obtain that I have gone for one tank and it holds 175 litres, if that runs out I have bought 2 paddles :D
Cbuf Rudder, you got me worried so I went out in the dark to check.... It is exactly as per Jacques details so will trust it right.

Dan cheers for the calc's. I know everybody has their own opinion on this and in the end I will have to decide, my feeling is that more buoyancy
IF PLACED IN THE RIGHT LOCATION !!! can only make the boat safer. At at this stage it is very easy to do.

Jacques do you want to comment on this ?

Ok so next subject.... the WC :help: Jacques I can not make the wc work. Please see my lovely sketch.

You will see above my stringers of which the lower one is 140mm deep I only have 1340mm the smallest pan is 375mm this leaves me 965mm, my head touches the roof... this is without a roof lining. Also I can not put it where the plan details as there is even less height and the door would have to be left open :lol: The study plans say 1500mm but this is from the hull.

So the question is can I reduce the height of the stringer to get another 50mm or more ???

Next question... Drilling holes through bulkheads. I am going to have to drill a 120mm hole through bulkheads F / G to get the exhaust pipe through, the pipe is 100mm. Comments please.

More to follow... Next job fit fuel tank, waste water tank, fresh water tank and bilge pumps.

Cheers

Les
189723A0-C997-4649-98EC-5AAC141B1230.jpeg
2F8567C3-7FAC-4EC0-91BA-5DA84AEDA048.jpeg

Post Reply

Who is online

Users browsing this forum: No registered users and 10 guests