Thread: Start Building Another Dutch GIS

Originally Posted by Daddles

Yeah, fitting the bottom single handed is a mug's game. I didn't have to go propping things up but I was lucky enough to have my son home at the time and got him to help lift the bottom onto the boat - that's all he did, just lifted it onto the right place then buggered off to go kick a football around but that little bit of help made a big difference.

I didn't flip it to clean up and fillet, that didnt' even occur to me I climbed underneath and just did a clean up which is really doing it the hard way. I'm still trying to work out who had the better idea (coz I'm still shy about glued bits around).

Richard

Hi Richard,

It probably would not have occured to me either.........but MIK's excellent manual told me " Flip hull upright ........and clean up any excessive ooze "
And I have three girls and a wife at home.......so I am really technically single-handed

Hi Watermaat

Haha, I like when you say you have sleepless nights thinking of solutions because either I'm normal or we're both nuts! Yes, I too play procedures over in my mind to work out how I'm going to do things, and I had thought of this method as I too will likely have to do this on my own. It's good to hear that the method works! The only difference is that I prefer polyurethane glue.

When you flipped the boat, did you find that the hull had twisted at all?

Well done, a marvelous job

I too like the idea of the tube bailers, but it's hard for me to comment without doing some measurements with a boat that is 3D like yours. I think two 2" made from plastic electrical conduit tubes is the way to go though, with maybe one medium size self bailer in the cockpit to clean out the remainder of the water. That will provide a substantial draining solution. Your idea of the cork balls attached to a shock cord is a good one, and would provide an excellent seal I would think. You could have the shock cord attched to some nylon line and run this though a loop to a cleat on the seat bulkhead. A knot will prevent it being washed out when it's released.

Sleepless nights must be part of the affliction as I, too, have been kept awake trying to figure out processes or procedures - and I haven't gotten to the hull yet!

Ralph, thanks for the commentary and pictures of your assembly method. I would not have thought of working from the middle out, but I can see how that is a good system when working alone (as I suspect I will be for assembly).

Great effort with excellent results. Thanks.

Bob

You know, with your drain holes, I WOULDN'T put any in ... yet.

You're changing the design so you can't use anyone else's experiences. So, wait until you've finished her (as in 'got her sailing'), then capsize her, tip her back upright and then work out where you want these holes, if at all.

My thinking is that the sealed, larger, centre seat is going to reduce the amount of water in the boat, it may even change how high the boat fills and once you've started using the boat, you'll have a better idea of what's a convenient place to put the holes (wouldn't it be a bugger to place one right under a natural position for a foot or your spine). Then you have the holes themselves - it's not hard to cut a hole in a hull.

Of course, I know very little about this sailing game

Richard

Originally Posted by woodeneye

Hi Watermaat

Haha, I like when you say you have sleepless nights thinking of solutions because either I'm normal or we're both nuts! Yes, I too play procedures over in my mind to work out how I'm going to do things, and I had thought of this method as I too will likely have to do this on my own. It's good to hear that the method works! The only difference is that I prefer polyurethane glue.

When you flipped the boat, did you find that the hull had twisted at all?

Well done, a marvelous job

I too like the idea of the tube bailers, but it's hard for me to comment without doing some measurements with a boat that is 3D like yours. I think two 2" made from plastic electrical conduit tubes is the way to go though, with maybe one medium size self bailer in the cockpit to clean out the remainder of the water. That will provide a substantial draining solution. Your idea of the cork balls attached to a shock cord is a good one, and would provide an excellent seal I would think. You could have the shock cord attched to some nylon line and run this though a loop to a cleat on the seat bulkhead. A knot will prevent it being washed out when it's released.

The hull is still a bit flexible, but if you turn it on horizontal places saw-horses it stays pretty much the same. But I checked again, to be shure it is okay after te epoxy has cured.
Regarding PU glue, I worked a lot with it and works well on a tight fit. Be aware that the gap-filling foamy part is not a very strong fixation ( I have experienced that )
I always used this glue in combination with stainless steel screws to be shure of overall strength.
I started using a pre-mix epoxy glue now ( tip from Joost ) and that works really well. Always the right thickness and it seems to stick more. In my area there is not that much price-difference anymore between PU and Epoxy glue. If I have a really tight fit and sufficient clamps I use Class4 PVA glue, since you can clean that before curing with water.

And I guess most boatbuilders are nuts?

Originally Posted by Watermaat

And I guess most boatbuilders are nuts?

Only the Dutch

Richard

Originally Posted by Daddles

You know, with your drain holes, I WOULDN'T put any in ... yet.

You're changing the design so you can't use anyone else's experiences. So, wait until you've finished her (as in 'got her sailing'), then capsize her, tip her back upright and then work out where you want these holes, if at all.

My thinking is that the sealed, larger, centre seat is going to reduce the amount of water in the boat, it may even change how high the boat fills and once you've started using the boat, you'll have a better idea of what's a convenient place to put the holes (wouldn't it be a bugger to place one right under a natural position for a foot or your spine). Then you have the holes themselves - it's not hard to cut a hole in a hull.

Of course, I know very little about this sailing game

Richard

I would like to wait untilI have some experience with this GIS before putting any "experimental" drain tubes...............but they need to go right trough my aft compartment so I need to get them in before closing the deck

I guess indeed Dutch are more nuts......................and it is stuffed with boats here

Originally Posted by Watermaat

I would like to wait untilI have some experience with this GIS before putting any "experimental" drain tubes...............but they need to go right trough my aft compartment so I need to get them in before closing the deck

I guess indeed Dutch are more nuts......................and it is stuffed with boats here

The worst that can happen is that you have to plug the holes. Easier than fixing Dutch Edam

Originally Posted by Watermaat

Hi MIK,

as we discussed before, I am very keen to get my GIS optimized in case of capsizing. I will probably sail 99% single handed and sometimes on bigger stretches of water with more severe conditions.

First thing: I will make a "boxed" central seat; one extra bulkhead that closes the front of the existing seat, placed left and right of the centerboard case. I will make this seat 40cm wide in stead of 30cm. Overall this will add significant flotation volume in the wide center of the boat, especially effective if capsized.

Second thing: I would like to use one or two draintubes through the aft compartment above normal waterlevel. These drains should be able get rid of a big amount of water after capsizing and leave much less water to bail out. These tubes will be in 2-3 inch range to have sufficient flow of water.

I found a picture where draintubes are seen in a Finn dingy Attachment 120036 , be aware that the Finn's floor is double, but still below water level ( they keep it low to optimize your hiking position ) . These drains take care of a mayor part of water, the rest is drained by a selfbailer in a well. It seems that Wayfarers have similar drains, but could not find pictures.

I would like your opinion ( and ofcourse from anyone else ) about where to position these two drain tubes.
Vertically : I am considering to have them placed just above the bottum wood in the transom ( bottum of tube about 5 cm above bottum of the hull ) and get them parallel to the seat top through BH4. This should make them almost parallel to normal waterlevel ? The bottum of the tube will enter through BH4 at about 10cm above the bottum of the hull.
I do not dare to place them much lower to avoid inlet of water in normal conditions, I will make a valve kind of closure at the transom end that keeps splash or waves out ( flap-type or perhaps cork-balls on shock-cord )
I do expect they will drain out lots of water, if you put your bodyweight in the back of the boat? Don't forget that this boxed middle seat will leave significant less water after capsizing.

Horizontally: Since GIS is floating deep on the side I probably need to have those tubes pretty close to the center-line centered at about 40cm from each other ? An option is to have one bigger tube in the center, but I need to sort out how that works together with fixing the rudder. One big tube slightly offset would be another option?

Any comment? idea's ? Tips ? Do's and don't's!

Thanks in advance
Ralph

Hi Ralph,

here some thaughts about flotation. Pro's and con's with additional flotation in the centre seat:
Pro: less bailing.
Contra: More windage and faster drifting capsized, daggerboard less reachable while swimming.

A possible solution for that dilemma could be a double bottom instead of the boxed centreseat ( only few additional flotation capsized, but more after righting, and fits good with draintubes). BUT that's far more changing of the plans and makes the hull a lot heavier. For myself I decided to stick with the orginal.

Draintubes: 50-75 mm diameter ore squared sounds good. Starting point for the tubes maybe lower corners of bulkhead 4, leading diagonally to the lower center of the transom some cm over the bottom, just a bit lateral of the lower rudderfitting each (gives more complete bailing than the higher entry, and works still with an angle of heel). Squaretubes give the additional benefit of a usable step while re-entering after a swim, but are not compatible with korkballs.

I'm just at his point of building and have not decided yet, wether just to proceed with the orginal and close the rear seat as next step (the nuts for the lower rudderfitting are in place now ) or to fit draintubes in. Refitting them if missed them after some capsize-tests is far more difficult.
Probably i will fit them in now but not cut the opening at the transom first, and decide later.

Greetings from Bonn - Jörn

Today I was able to try out if my outboard cut-out works well...dry ofcourse.
Seems okay? As expected I am not able to turn the outboard 180 degr for a sudden reverse action.............but if you lift it a bit, it can be turned 180, so I can use it in reverse to get GIS backwards ( to leave a ramp f.e.)
Few pictures attached

I have started a new thread regarding my flotation and drainage question .

I am making my enclosed central seat now.
I have started making an extra bulkhead that will close the front of this seat.
I made this 40cm in front of BH3 and used a similar construction as BH3 but facing towards the front. I first made this in one piece since that's easier. Attachment 120287 and Attachment 120288 I did a dry-fit, predrilled screwholes and removed it.

Next step was putting the centerboard in, following plan. I did a dry fit after carefull alignment. I made this front support and did a dry fit too. And I cut my extra BH in two symetrical halfs, after carefull measurement. In these pictures you see a complete dry-fit of all rough components including seat supports. I have cut the seat ply too to get an idea.
Attachment 120289, Attachment 120290, Attachment 120291.

As you see it is a big box, 40 cm long x 32 cm high giving about 150 liters of extra flotation and dry storage in the middle of the boat. It also gives a additional strength to the sides and centerboard case. This at a very low weight penalty; the extra weight of this bulkhead plus 10cm wider plywood seat is about 2kg finished. The rest is plan.

This is a view inside, I still need to make left and right drainage channels.
Attachment 120292.

There are some disadvantages too, you are not able to store longs things on the floor anymore and you miss a nice storage place for a big bucket.............but by the famous words of our football player Johan Cruyff " there is not any advantage without any disadvantage "

Hello all,

I visited Ralph yesterday afternoon to admire his new build and I can attest that his GIS is looking very clean and crisp.

It is nice to see some new ideas tried out like the European pine that is readily available at the local lumberyard used in the boat and spars, the arrangement in the transom for the engine, the boxed in mid-seat and the drain tube(s) that will be placed under the aft deck.

Next spring (should start early April in the Netherlands) we should be able to do some side by side sailing with our boats (we live in the same area about a 30 minute drive apart) to do some testing of the different rig set ups and sails.

Best regards,

Joost

Looks great Ralph! The curved seat top where it joins the cb case is also a nice touch.

I am wondering how you are finding the Class 4 PVA to work with as a construction glue?

Also, will you be installing tubes for drainage through the enclosed bulkhead?

Originally Posted by woodeneye

Looks great Ralph! The curved seat top where it joins the cb case is also a nice touch.

I am wondering how you are finding the Class 4 PVA to work with as a construction glue?

Also, will you be installing tubes for drainage through the enclosed bulkhead?

PVA Class 4 works well, but you need flat surfaces ( it is bad in gaps ) , sufficient pressure ( lots of clamps or screws ) and a nice temperature ( if it is cold it takes ages to dry ) . If done well it is as strong as epoxy and I found it stronger than 1 comp PU. I used PVA Class 3 too, and that works better at lower temperatures.
It's nice to use it for small jobs since you can clean things with a piece of wet cloth and you do not need to mix ( no left overs ) . I build my spars completely with PVA class 4 and last years Seagull completely with PVA class 3 exept for the glas-tape chines. But I do really soak every seam with epoxy afterwards and give it a good overall coating to close it off.
For GIS chines and final assembly I use epoxy, in a nice pre-mix glue version.

I will make wooden drain-channels on the bottum, I will probably be able to post pictures tomorrow.

Best Regards