Thread: Start Building Another Dutch GIS

Ralph,

I like what you are doing with your GIS, and I admire your workmanship.

Here is one possibility to minimize water flowing into the boat from the drain-tubes.

Duckworks Boatbuilders Supply

Might not be the right size?

Thanks for your posts and ideas.

Bob

Originally Posted by Watermaat

Hi Bjorn,

Thanks for you nice comments, I agree with your pro's and con's.
I decided to go for the boxed seat since you probably have a more stabil boat after returning it from capsize ?

Regarding the drain-tubes, I was thinking to keep these tubes horizontal ( or even a bit downward ) to avoid water comming in ? These corkballs will stop splashes, but are certainly not water-tight.
Placing them more to the sides could be nice to empty when heeling, but would they let water in if you are heeling in light winds?
That square tube / step idea is certainly worthwile to consider. Some dinghies used square plexyglas hinged flaps to stop water and that could work well in this case.
Smart to consider placing tubes but not opening them before you have tested GIS . But it is still a complex question were to place them anyway

Thanks

Hi Ralph,

nice work you did, and thanks for the thanks.

With the tubes my idea is to start low in the boat, floating level or heeled, and end in the transom up and central, so good drain with weight = sailor shifted in the back quarters, and transom opening well out of the water with normal trim, again heeled or level. Therefore the diagonal way for the tubes from bulkhead to the transom.

Flaps are part of the game, but for the looks probably just the cutout, if I can manage.
for waterproofing there is clear tape (again for the looks )

Greetings from Bonn - Jörn

Originally Posted by BobWes

Ralph,

I like what you are doing with your GIS, and I admire your workmanship.

Here is one possibility to minimize water flowing into the boat from the drain-tubes.

Duckworks Boatbuilders Supply

Might not be the right size?

Thanks for your posts and ideas.

Bob

Hi Bob,
thanks for your kind words .
Great tip!
That seems close to the right size if I use 2inch tubes.

best regards
Ralph

Originally Posted by joern

Hi Ralph,

nice work you did, and thanks for the thanks.

With the tubes my idea is to start low in the boat, floating level or heeled, and end in the transom up and central, so good drain with weight = sailor shifted in the back quarters, and transom opening well out of the water with normal trim, again heeled or level. Therefore the diagonal way for the tubes from bulkhead to the transom.

Flaps are part of the game, but for the looks probably just the cutout, if I can manage.
for waterproofing there is clear tape (again for the looks )

Greetings from Bonn - Jörn

Hi Bjorn,

I better understand now and it probably works well draining. I guess you have a dinghy background? That's indeed the way it should empty quickly. Get some speed, move your bodyweight aft and the bulk of water flows to the back and out.

I still have my doubts about some water draining in? These tubes are directed a bit downward to the front. Since they are diagonal, when you are heeling this downward angle does even increase for the lower one. That means that every drip or splash will drain towards inside.

I also would like to avoid any flap or valve, so that's why I was thinking about two parallel and horizontal ( or even slightly downwards to the back ) 50-60mm tubes centered about 20-25 cm from the midline. Alternative could be one 70-80mm tube just off center passing the rudder mountings.
These would probably not drain as much as your solution, but have a greater chance to keep the boat dry under normal conditions.
As far as I talked with Joost, GIS is not the type of boat that flips over regulary ( even doing the Caledonian, he was never able to capsize GIS........so he thinks it's nuts to bother about that anyway ) I would not like a set-up that gives me a wet behind under most conditions .
Clear tape is actually a nice solution ( forgot about that ) , works really well without aft-deck when you can simply push it out. But for GIS you need to reach out or swim............but you get wet anyway capsizing .
What do you think about additional selfbailers ? http://http://www.martinvanleeuwen.nl/Zelflozers.htm ( in Dutch, but being German you probably understand a bit )
I probably make those tubes now ( before closing te deck ) and have these as an extra if it appears I need to them. You can fit them later, two ones in both sidecorners will keep GIS completely dry.

Best Regards
Ralph

Hi Ralph,


thanks for the link, but the site is currently not aviable. I will try later again.

You are right, every splash that which will reach the transom opening will follow the slope downward to the cockpit.
But with the pirates and 420's I sailed earlier in my life, there were only few drops at the transom if the back edge of the bottom was sharp. OK, if you lay at a mooring and a stinker's wake comes from behind... but there is the flap for. And with a high opening in bulkhead 4, there will remain a lot of water in the cockpit after a righting. With so much water left, I think the effort of fitting draintubes may be to much.
With self-bailers e.g. Elfström-type - they are great with speed, but never really tight. for a racer they're great, and if the bottom of the cockpit is higher than water level like with a Valk or a Randmeer they're also fine for tourers - but I remember some some unfortunate effects with closed Elfströms to our sleeping bags when one of our crew stepped on the side deck preparing to jump in the water for a morning swim.

Shortly - I don't like selfbailers.

Greetings - Jörn

Originally Posted by joern

Hi Ralph,


thanks for the link, but the site is currently not aviable. I will try later again.

You are right, every splash that which will reach the transom opening will follow the slope downward to the cockpit.
But with the pirates and 420's I sailed earlier in my life, there were only few drops at the transom if the back edge of the bottom was sharp. OK, if you lay at a mooring and a stinker's wake comes from behind... but there is the flap for. And with a high opening in bulkhead 4, there will remain a lot of water in the cockpit after a righting. With so much water left, I think the effort of fitting draintubes may be to much.
With self-bailers e.g. Elfström-type - they are great with speed, but never really tight. for a racer they're great, and if the bottom of the cockpit is higher than water level like with a Valk or a Randmeer they're also fine for tourers - but I remember some some unfortunate effects with closed Elfströms to our sleeping bags when one of our crew stepped on the side deck preparing to jump in the water for a morning swim.

Shortly - I don't like selfbailers.

Greetings - Jörn

Hi Joern,

( sorry I was misspelling your name )
The link was towards these Elvstrom selfbailers, but you knew them.
I do agree that these are sometimes leaking.........that's why I wait to build them in
I am thinking about lowering these tubes so there exit will be closer to the bottum edge of the transom ( like 2 cm higher ) and still leave them a bit upwards to the front. They will probably end up 7cm above bottum level, so will drain a bigger part and still do not reverse water from outside.

best regards
Ralph

The box-seat construction is now fixed with epoxy-glue. These pictures also show the drain channels through this compartment. First I need to coat things with epoxy and than I put a ply "lid" on both channels to close them. Attachment 120406, Attachment 120407.

I have also started the aft deck construction. You will also see a similar drain-channel on the port-side which will be closed by a drainplug through the transom. This channel allows to drain water that has collected in GIS ( rain or gardenhose cleaning ) on shore. It drains if you put the bow up a bit. Attachment 120408 . I thought this was very convenient in the Dutch "wet" season.......which is about 12 month/year .
I will put a big porthole in this deck, central close to the transom. This will allow me to reach the rudder mounts and it's not in the way if you want to sit on this deck.

It is a good idea I think to put the port there.

I have done enough threading of fittings and taping nuts into spanners or on the end of adjustable spanners on the ends of sticks to have some patience with those methods. But the port makes it very easy.

MIK

I am making GIS deck construction now. I try to make it "bomb-proof " to be shure nothing breaks inside these flotation tanks in case you fall down on it. I use light fir ( pine ) and very light poplar ply, so there is not much additional weight doing this. I first make a dry-fit of all parts, at a later stage I will glue things in place with epoxy.

Front deck beam has a T-shape since a large inspection port will be in the front triangle. I will use a ply doubler around this inspection port in the deck-ply.
Attachment 120622 , Attachment 120623 .

The aft deck has two parallel beams and you see ply doublers on BH4 where both drain-tubes will pass this BH. They also give additional support to the deck-beams.
You will also see a wide ply doubler on the transom, where both drain-tubes will pass on the sides and the rudder mount will be fixed centrally.
I will also use a ply doubler around the aft inspection port in this deck-ply.
Attachment 120624, Attachment 120625 .

The central box-seat has two extra deck-beams to get some additional support in the deck-ply. Attachment 120626

Making this is a nice real "woodwork" job, but time-consuming to get it done well.
Don't do it in a late afternoon rush if you have promized to go out for dinner with your wife.................

I have started making the gunwales for my GIS. They are made of one 18mm european fir plank, covered with 15mm hardwood. I did not make a bevel, but made them both 27mm high. I used clamps to fix them and get the right alignment. They are brought up 3 mm to the bow and 2 mm to the transom as per plan to get a nicer look. After that I used stainless steel machine-screws to fix them dry.
Attachment 121219 and Attachment 121220 .

I also made both straight side-arms on BH4 and dry-fitted them in place after measuring and cutting the aft-deck ply. Attachment 121216.

Both curved side-arms on BH2 are also made to fit existing curve of both ply sides.
They are dry-fitted in place after the front-deck ply has been measured and cut.
Mast parters and step are made and will be fully epoxied before gluing them in place.
Attachment 121217 and Attachment 121218. ( In general I try to epoxy most parts before fitting them in place if possible. It's a much nicer job to do that standing on a workbench, in stead of being bend over in your hull )

Next step is to fix these parts with epoxy-glue.
NB: I personally like to have things measured, made and fixed with screws without glue. This gives me more time to have things done well, without the time-pressure of curing glue. After that I remove screws, put epoxy-glue and re-screw things back in exactly the same place. This takes a bit more time, but I can avoid lots of stress messing around with loose bits of wood, clamps and messy epoxy everywhere

Originally Posted by Watermaat

NB: I personally like to have things measured, made and fixed with screws without glue. This gives me more time to have things done well, without the time-pressure of curing glue. After that I remove screws, put epoxy-glue and re-screw things back in exactly the same place. This takes a bit more time, but I can avoid lots of stress messing around with loose bits of wood, clamps and messy epoxy everywhere

I'm the same, though I prefer to use clamps when I can - I don't hesitate to reach for screws if needed but will use clamps by preference (fewer holes to fill). Apart from that though, I always dry fit and practice to make sure the impending disaster is fully planned

Richard

Originally Posted by Daddles

I'm the same, though I prefer to use clamps when I can - I don't hesitate to reach for screws if needed but will use clamps by preference (fewer holes to fill). Apart from that though, I always dry fit and practice to make sure the impending disaster is fully planned

Richard

You are right about clamps preference, but I still like to use at least a few screws ( or pinholes with nails ) to avoid parts to slip away ...........and have an unplanned disaster

Originally Posted by Watermaat

I have started making the gunwales for my GIS. They are made of one 18mm european fir plank, covered with 15mm hardwood. I did not make a bevel, but made them both 27mm high. I used clamps to fix them and get the right alignment. They are brought up 3 mm to the bow and 2 mm to the transom as per plan to get a nicer look.

Hi Ralph. Nice work going on there.

This is probably one of those things in the plans that becomes more apparent when you get to that stage and have an “aaah” moment. Well, I’m hoping so in my case!

Do you lift the gunwale above the 33mm line or above the sheer?

Originally Posted by woodeneye

Hi Ralph. Nice work going on there.

This is probably one of those things in the plans that becomes more apparent when you get to that stage and have an “aaah” moment. Well, I’m hoping so in my case!

Do you lift the gunwale above the 33mm line or above the sheer?

Since I did not make the bevel, I started with 27+mm wood in stead of 33+. So I also started with a 27mm below shear line. That whole 27+mm plank is lifted above the 27mm line at the bow and transom. If planed down flat with the designed shear ( edge of plywood ) this will result in a light taper towards both ends. ( similar will happen if you do that with the 33mm bevelled plank as per plan ) . I hope that's clear?

NB I will make a slightly different gunwale and inwale. The gunwale made of 18mm softwood and 15 hardwood capping; square 33mm wide by 27mm high. The inwale made of 18 mm softwood on 27 mm softwood spacers; square 45mm wide by 27mm high. This gives a wider rail that eleminates the need to bevel the 45mm side-arms. Since overall height is less than plan, it also keeps weight down and gives a slender look. There is nothing wrong with the original plan, but this is just my personal idea to slightly adjust things to "perfection"