Keelbox height and other questions

[someoneON]

Hi!

Im building the long cabin version, the hull almost done, but i have some quick questions since the weather is still epoxy-friendly and will be for a week or two, so i have to act fast.

1.The keelbox in the plan is about 8.3 inches high, and i did it by the plan, but its not yet glued in. I have plenty of room to make it higher, but its nice and low in the cabin now. I wonder if that is enough or should i make it higher, would i benefit any off of it? Or is it sufficient as it is in the plans? I was concerned cause of a video on youtube with a pulldown test and the keel was bendind quite much. Keelbox wont have a sleeve, the keel will be rectangular on the top to fit the rectangular box.

2.Compression strut-i did a wooden one, its also not yet glued in, its dry and hard oakwood, one piece, lathed to 60mm in diameter. Should this be enough or should i consider the aluminum one? the rigging will be the same as on Seascape 18, which has only front stay and two sidestays so the force under the mast is larger that on 5 point.

3.Berths-i went with full berths option, supports are 2 pieces on the bottom and cleats on frames, should i make supports (cleats?) on the sides too?

Thanks in advance, i have to go to glass some pieces in now

[Kevin]

First, Hello and welcome.

I know that TTB had a short keel box and never complained about it. I have a 10" keel box and it works fine. Any flex of the keel you saw in a pull down test was probably because of the keel strut not being quite strong enough. In general, I think you need lots of things to going wrong to get the boat on it's side. I was out in 15-20 last Wednesday 2-up and we never got close to getting the keel out of the water.

Compression post sounds like plenty to me. But your concern should be the amount of tension you need to get and keep your desired pre-bend. My rig needs 550 lbs on the shrouds to get me into the ball park. I also have a single spreader rig. The Uppers will have most of the load and the diagonals will be there to limit how much bend you get.

I just used a fillet and tape to the hull side for my bunks. I did not see the need for a cleat there because of the angles involved.

Cheers. Kevin.

p.s. Where are your located?

[someoneON]

Thanks for the reply, im located in Slovenia, Europe. I think that mine is the only one in our country nearing completion, i know for 4 people that purchased the plans, but none seem to finish the project, some didnt even start. I bought my plans from a friend in Croatia, five guys building five boats one for eachone of them in their garage, good people.

Mine is also heavily modified, me and my cousin, who designed Seascape 18 made some modifications to the plan for practicality and performance, mods include dry ice fridge, complete electrical wiring with fusebox and control panel for lights, sound system, cabin and cockpit illumination as well as underwater lights, power outlet, solar panel and all that stuff, mounting points for everything to fit seascapes rig and all the gear, gennaker sock and rudder. Instead of 3 bunks as in plan im going with one double and two trunks for luggage.

"I just used a fillet and tape to the hull side for my bunks." -ill leave watertight compartments under the bunks, that means bunks are taped only from the outside, and are just glued to the supports, since i cant get in through inspection ports, cause there will be none. Should i make supports wider for the bigger contact area? Or is the 6 or 12mm at some points enough contact with supports?

Sorry for too much questions but i want to do as much as i can during these few warm days that are left.

[Kevin]

I fully understand the desire to get things done while it's warm.

I put inspection ports in my bunk compartments because I was warned to not leave a compartment that I couldn't inspect. I don't know if that was perfect advise, but so be it. I didn't tape the underside of the bunk to side panel joint. I doubled the top of the stringers with 2nd strip of ply to give me something to glue the bunks down to. I then glassed the top of the bunks so that center joint is in effect taped as well.

[jray]

If it helps you out I've been sailing a long cabin version for two seasons now. The keel box was built to the plan height and I haven't had any problems with water in the boat and I've had her in some interesting angles of heel. I did sleeve the box so I don't have any information on how you are approaching it but don't believe you will have any problems with the height.

No help on the compression post. I used thick gauge 1 1/2" aluminum tubing with plates welded top and bottom. Probably overkill but it has been working great. As to the bunks I did the same as Kevin just fillets and taping the edges.

[ryderp]

Welcome to the fleet.

I'm using a mahogany compression post about the same size as yours and it works fine. I notched the post and bolted it to the frame 89 instead of gluing it so that I could take it out or change it if necessary. Hardwoods like oak or mahogany can take an incredible amount of compression force so I can't see how this would be a problem.

I have a short cabin boat, so I can't comment on your keel sleeve although I've definitely had my keel out of the water (the result of trying to reach in a good wind with a 49 SQ Meter spinnaker) and haven't noticed any significant bending of the keel.

Phil

[someoneON]

So, Onwards

Weather went really bad these days, temps droped bellow 16 celsius and its raining like crazy.. So ill just have to have some indoor fun with the keel itself.

Ill have 14.5 sqm mainsail, 8sqm jib and 32 sqm gennaker, i think the short keelbox will do.

Oh, one more question, when i started the build i bought one ply board more just in case, and i have it left now. I was thinking to do the cockpit floor between frames 124 and 169 a single piece going all the way from side to side, so it would go "under" the sides. Is this a good idea? I also wanted to do that for between 169 and stern, but its already cut as in the plan.

PS: To Big_Dog, i cant send private messages for some reason, if you wish i can answer it all here.

[Chad]

Re: the cockpit sole going all the way to the hull sides-
You'll get a small benefit structurally by creating closed boxes that will be better in torsion, which is good. But, you'll add weight and create areas that are almost impossible to access. I've spent a lot of time head-aft in the space behind f124 installing hardware on the cockpit sole, and all that would be impossible with a full-width sole.

And, there's other, better ways to get the torsional benefits of the wide sole panel- installing full-depth girders under the sole to the hull bottom, for instance. This stiffens the hull bottom, stiffens the boat longitudinally, and creates a sort of torque tube as well, and with the added weight lower down in the hull.

[someoneON]

All my stringers and supports, under the bunks and under the cockpit are floor to bottom one piece without lightening holes.

[DavidD]

Hi all

A little off topic but sill on the topic of keel boxes. Has anyone got any advice on a locking mechanism to keep the keel in the "up" position. I would just feel so much more at ease when putting it on the trailer with the keel being locked.

Kind regards

[micah202]

Hi all

A little off topic but sill on the topic of keel boxes. Has anyone got any advice on a locking mechanism to keep the keel in the "up" position. I would just feel so much more at ease when putting it on the trailer with the keel being locked.

Kind regards

...I usually keep the block and tackle in place,,attached to the main halyard.

...I'm sure there's a more complicated way to do it,,but cant think what it is!?

[Chad]

A couple 1x2" sticks, the right length to jamb under your keel top plate and sit on the deck, maybe a spring clamp across the trailing edge to hold them in place? -if you don't trust that main halyard cleat...

[DavidD]

Yeah that was my thought - a couple of steel or alloy rods that jam under the top plate.

I was also thinking of some sort of collar that goes around the keel on a hinge and tightens up but that could slip.

Kind regards

[Chad]

pine sticks would be fine...

Kevin had some snazzy little inflatable wedges he used for trailer transport, that slid between the keel case and foil when it was up. He said they are sold to towing companies for wedging doors open, or something like that.