LB26

[jacquesmm]

Correct. That final layer is not structural or play a only a small role. It's function is to end up with a fine weave, easy to sand. You can use something lighter than 200 gr if available.

[fallguy1000]

100g woven is probably available, easy to work with as well.

[les2021]

Hi Dan

Thanks for the last lot of info.

Sorry it has been a busy week, trying to get all the spring house and garden stuff done before I disappear into the workshop....

If all goes well I should start the molds end of this coming week !!! I have read and re read all the threads and studied the plans, I think I am happy apart from a couple of points that may affect the molds.

JACQUES / GUYS

I have drawn the stations to scale and I am ok with the transom mold attaching to 9+ this then gives the correct boat length.

As per REEFIE'S masterpiece I am planning to fit a bow thruster any thing I need to know beforehand ???

IMPORTANT ONE... Are there any structural details regarding the towing hook for winching the boat onto a trailer ???

The CHINE SPRAY rail I understand it can be fitted later. BUT Jacques mentions the LB26 has a CHINE STEP !!! I can not find this detailed anywhere ( it could be me ) If this is so surely it will affect my station molds ???

JACQUES / GUYS HELP can anyone enlighten me ? A SMALL SKETCH LOOKIN THROUGH FROM THE TRANSOM WOULD BE GOOD ! ( chine spray rail and chine step )

I am still tackling the Greeks regarding the fibreglass !!! but think I am almost there.... It seems though due to Covid supplies are low and prices are high !!! WHAT A SURPRISE.....

Cheers

Les

[fallguy1000]

Hi Dan

Thanks for the last lot of info.

Sorry it has been a busy week, trying to get all the spring house and garden stuff done before I disappear into the workshop....

If all goes well I should start the molds end of this coming week !!! I have read and re read all the threads and studied the plans, I think I am happy apart from a couple of points that may affect the molds.

JACQUES / GUYS

I have drawn the stations to scale and I am ok with the transom mold attaching to 9+ this then gives the correct boat length.

As per REEFIE'S masterpiece I am planning to fit a bow thruster any thing I need to know beforehand ???

IMPORTANT ONE... Are there any structural details regarding the towing hook for winching the boat onto a trailer ???

Well, it would be wise to lay in some 20 pound or higher density coosa in the area of the hook. On my boat, it was an afterthought and cost me a small fortune. I spent about $700 on two machined eye bolts made 10" long and a butterflied piece of 12" stainless for bow hooks. My Skoota has a very narrow bow and in order to glass it up, it required 10" long bolts plus the 2" eye. Since I failed to get the proper core in there, I also needed to butterfly stainless to give the hook some lateral strength. Even a pull at sea might pull port or star and damage the core. For you, same concern. So, put a core in there before you start that is strong enough to not smash. The hull core is too light. I don't recall of JM catches this in the plans. Since the transom of the LB can be made lighter iirc; the same is true back there. Make a section of the transom with core material of 20#/cuft minimum density. I would say a piece of core about 8"x8" would be nice, but perhaps even 6"x6" would suffice. If you don't have access to such cores; you can also make them from solid glass, but that can't be done in a single go or they might catch fire. And solid glass chunks like that are a ton of work to make to say 15mm. I believe the 600/225 glass is about 1mm per layer, so you'd need 15 layers to get the thickness. But is an option if no alternative. Also, if you must build solid frp, measure and just build it 2" beyond the hook holes each way to reduce the effort. Solid frp is also stronger than coosa.


The CHINE SPRAY rail I understand it can be fitted later. BUT Jacques mentions the LB26 has a CHINE STEP !!! I can not find this detailed anywhere ( it could be me ) If this is so surely it will affect my station molds ???

I am not sure. I don't recall a chine step. I believe what you read is that a chine flat/step can be added. This is a touchy subject with boats and can create problems. I would only follow JM advice; otherwise add a rail. A step can create chine walk. It does reduce the spray quite a bit, but again, Mertens is the guy unless someone with the LB26 has done it. PS-JM calls the edge of the hull a tumblehome step. I think he will not advise a flat and only a rail. A rail is added after glassing the entire hull, and after fairing the hull, but before paint. Paint bonds are very weak vs epoxy.

JACQUES / GUYS HELP can anyone enlighten me ? A SMALL SKETCH LOOKIN THROUGH FROM THE TRANSOM WOULD BE GOOD ! ( chine spray rail and chine step )

I am still tackling the Greeks regarding the fibreglass !!! but think I am almost there.... It seems though due to Covid supplies are low and prices are high !!! WHAT A SURPRISE.....

Cheers

Les

[les2021]

Hi

Cheers Dan

Jacques can you come back with any comments.

Thanks

Les

[TomW1]

The chine is where the side and bottom meet. A chine step is a indentation of the bottom so that there is a cut out from the chine usually at a slight angle and then downwards to the bottom. You should be able to see this on your frame plans. This helps in steering and in handling rough water as they help stabilize the hull. Please post some pictures as you build your LB we have never seen a complete one built.

Keep posting and don't be afraid to ask questions Jacques will be following your build and all of us can help. Fallguy is getting close to finishing his foam boat, though he used vacuum bagging on a lot of his parts.

Good luck and keep posting.

Tom

[jacquesmm]

One item at a time:
- chine and chine step: there is a chine and if you add a rail, it becomes a chine step. There is no true chine step in the design but I think one builder has added one. Not necessary IMHO.
- at the transom, along the side, the swim platform extend along the sides. That edge can be be called a chine fender. It protects the side along a dock and acts as a chine step. I recommend to build her that way.
- towing hook: she is not designed to be towed but she can be towed and have a towing/trailer hook. In that case, the core should be replaced with high density foam or build up thick in single skin just as I show in the foam sandwich tutorial.
- bow thruster: the same way: where a bow thruster tunnel is fiber glassed to the hull, the hull must be either a thick single skin or the core must be HD foam.

[fallguy1000]

I found that Mertens answered this a bit in another thread.

The hull of the LB26 at the dwl has tumblehome which will act as a splashrail.


The thing I would be more concerned about is what impacts the dock.

I am not by the plans now, but check the plans on the aft stations and if the hull can get dock rash; add a splash rail.

[les2021]

Morning All

Thanks Tom / Dan / Jacques

Bit of a worry that nobody has posted past building the hull ( divorce maybe !!! )

Jacques thanks for your input. Let me see if I have this clear in my head ( empty head )

On the Deck and Superstructure drawing. On the top detail you show the swim platform only, on the bottom detail you show the swim platform only, on the middle detail if I read this correct you show a 102mm thick swim platform approx 160mm above DWL going to station 9 BUT the lines continue to the bow ? Is this the spray rail you are describing in your post tapered to the bow ? I am not sure my assumption is correct as the top and bottom detail clearly show just a swim platform....
If I decide to build the swim platform in teak or similar what would be the fixing connection of the side arms to the hull ?

Regarding the tow hook. Inserting high density not a problem, should I also build up layers of high density inside to create a thicker block, if I try and describe it... a triangular block in the bow 80mm thick ?

Tom I will start posting photos the second I get started, thanks for the encouragement.

Cheers

Les

[fallguy1000]

Be a bit careful on the thickness of the bow hook area. If you buy a standard hook of say 3", you can't go to 80mm thick. And paying for a custom made hook is super expensive. Mine were ridiculous; it was like 700 for the two. Still a bit mad about the cost.

Buy the hardware and then build to it.

Usually, you want a considerable backing plate for the hook as well. Mine are stainless about 14"x2". What you want to do is a calculation of the hulls mass.

For example, my boat is about 10,000# or a bit less.

At 25 square inches of backing plate, this is 200 psi, if two tow hooks are used 100 psi, but in towing, one hook can do all the work now n then.

No backing plate and one inch washers is 5000 psi.

The thickness of the core is less important than putting plenty of glass up there and making it flat enough for the backing plate. For you to achieve 100 psi on the hook, if the boat and gear is 4000#, you need say 3" wide by 14" long backing plate. The backing plates are best made with scraps of leftover glass. You can make them from 6 layers of 1708. I am going to remake some of mine as a kaizen later. Solid frp is best. So get the hook and make a flat spot however you can and wide enough for a backing plate that can get your psi ratings low enough. I grasped at straws on numbers I felt were reasonable.

My back hooks are four hooks with about 9" of backing plate each. So, a total of 36" of backing plate of you bridle rope the tow which you must. The worst is pressure on one bridle or 18", I'd be comfortable pulling something at 200 psi or say 3600 pounds. Not sure whether I am correct a bit on the ratings, but was my approach.