Elephant Drains

[captnjack]

Originally Posted by two stroke mick

I retro fitted my trunk to the Valiant DR 490. It is about 1 hrs work. Time well spent and very easy to do.

Do you have pictures of how you did this? I would love to find a kit which provides a trunk attached to a plastic fitting I can just glue into the proper size hole.

[whisper]

I used one of these on my first searider:

http://www.rib-shop.com/product.asp?...hFor=&PT_ID=29

[captnjack]

Originally Posted by whisper

I used one of these on my first searider:

http://www.rib-shop.com/product.asp?...hFor=&PT_ID=29

Awesome, seeing if they will ship internationally...

Besides the Avon's which sometime come with trunks, most RIBs over here don't have them. I am asking my builder if he'd be will to make up something exactly like this too.

[MI3GTO]

Would any of the folks that have fitted a trunk to a SR4 care to share the position and dimensions they worked to please. e.g. was the bottom of the hole flush to the deck surface, how far from center line? thinking of fitting one (two?) as I really don't trust electric pumps on their own. GS

[Jizm]

We used to fit these scuppers, can't comment on longevity but they seemed to work ok.

[Smithyyy]

Originally Posted by Oscarguitar

Boris,

The trunk creates a big hole in the transom and my worry is that the trunk will tear without me knowing and fill the boat up with no way of easily stopping flow!

Can happen - first time I left my boat on a mooring overnight in wind and waves we came back next morning to find a split had developed near the end of the tube (ie the higher end with the tube hitched up on the transom), had been dipping under the water, and the boat had progressively swamped. Cue a big bucketing session...

But I've still got the trunk (with a new tube!). Best way by far of getting rid of lots of water in a hurry.....

[captnjack]

Originally Posted by Jizm

We used to fit these scuppers, can't comment on longevity but they seemed to work ok.

I have something comparable right now, its not a big enough hole to move out water FAST. Post-stuffing the bow into a wave you are riding so low that subsequent waves like to come aboard for the party too...

[two stroke mick]

I) I filled a tablet box with Firbregrass resin.
2) I placed the tablet box into the original 2" hole and sealed it into position with sika flex.
3) I cored out a 70mm hole with a core bit on a drill
4) lined the sides of the hole with sika flex.
5) Inserted the pipe section.
6) placed some sikaflex on the outside of the pipe section and placed the trunk over it.
7) used a clip to hold the trunk in place.

NB drill from the inside out not the other way around or you may get your levels wrong and cut up the deck.

TSM

[9D280]

Originally Posted by MI3GTO

Would any of the folks that have fitted a trunk to a SR4 care to share the position and dimensions they worked to please. e.g. was the bottom of the hole flush to the deck surface, how far from center line? thinking of fitting one (two?) as I really don't trust electric pumps on their own. GS

Most ribs with the "Searider shaped" floor (i.e it's not flat all the way to the toobs) have them as far apart as geometry will allow. Bottom of the trunk hole needs to be flush or thereabouts with the floor, and in the case of the SR, the slopey bit of floor tangentical to the bit of the hole that is nearest to it, although that is not hugely important - it's just that the closer you get to the corner, the more water you get out.

Originally Posted by captnjack

Do you have pictures of how you did this? I would love to find a kit which provides a trunk attached to a plastic fitting I can just glue into the proper size hole.

I'm sure there are plenty out there, but you still need to drill the hole & more importantly seal it!


TSM has a very good point about drilling, however just to throw a spanner in the works, mine has the hole drilled with the cutting diameter about a plastic pipe's wall thickness below the deck, in order that the bottom of the inside of the pipe is level with the deck. Mine was drilled, resin coated to seal, then the plastic tube sikaflexed in. (hypalon trunk ditto to the plastic) That has the advantage that when the sika finally time expires, you still have a sealed transom.

[two stroke mick]

Photos of trunk as installed

[captnjack]

Originally Posted by 9D280

I'm sure there are plenty out there, but you still need to drill the hole & more importantly seal it!


TSM has a very good point about drilling, however just to throw a spanner in the works, mine has the hole drilled with the cutting diameter about a plastic pipe's wall thickness below the deck, in order that the bottom of the inside of the pipe is level with the deck. Mine was drilled, resin coated to seal, then the plastic tube sikaflexed in. (hypalon trunk ditto to the plastic) That has the advantage that when the sika finally time expires, you still have a sealed transom.

I'm just putting a single one in and have the luxury of not worrying about how the transom wood is encapsulated as its an Ali hull. I found an Ali drink cup holder which is the correct diameter (3-5/8"). I think I am going to cut the bottom off that and use it as a transom tube. While I could have it welded in, I think I will use sikaflex as well, gives me more options in the future. I need to find a hypalon supplier and glue still.

[9D280]

Originally Posted by captnjack

I'm just putting a single one in and have the luxury of not worrying about how the transom wood is encapsulated as its an Ali hull. I found an Ali drink cup holder which is the correct diameter (3-5/8"). I think I am going to cut the bottom off that and use it as a transom tube. While I could have it welded in, I think I will use sikaflex as well, gives me more options in the future. I need to find a hypalon supplier and glue still.

Polaris hull... of course. In that case yes, your theory will work fine. With the only real decision being "do I want to turn to port or starboard to completely empty the hull". If you have a Aux / Kicker then the decision is probably fairly easy, as the "up" trunk will likely foul the kicker.

I guess any watertight "hose" would do the trick. The hypalon on the Avon / Humbers is because it's what they have plenty of offcuts of to make them with!

[sirewan]

7) used a clip to hold the trunk in place.
TSM[/QUOTE]

Just got new elephants trunk through today. Is it worth sleaving over the old one? or Cutting the old one off completely? It looks like it goes into the transom? could this be the case? and should some sort of sealant/glue is that the flex stuff? be used between trunk and pipe as well as clip? Cheers

[captnjack]

Originally Posted by 9D280

Polaris hull... of course. In that case yes, your theory will work fine. With the only real decision being "do I want to turn to port or starboard to completely empty the hull". If you have a Aux / Kicker then the decision is probably fairly easy, as the "up" trunk will likely foul the kicker.

I guess any watertight "hose" would do the trick. The hypalon on the Avon / Humbers is because it's what they have plenty of offcuts of to make them with!

I have an L shaped bracket on the port side for the transducer so that limits my choices.

I figured a single 4" diameter trunk has double the cross sectional area of 2x 2" diameter trunks hence the single large one is more effective from that perspective too. I can't really empty the hull anyway as water can flow from the deck into the bilges and I can't mount the trunk that low. Its just to evacuate a big wave. Bilge pump can handle the residuals.

[Erin]

Originally Posted by boristhebold

Last Sunday was pretty horrible with the lareg waves up the swash, I used my time as a practice session going againts the waves at slow speed and then riding them coming back, good practice I would say, bit scary at times but helps me on experience of big waves. The Rib coped brillinatly, the trick was slow speed heading into the waves allowing them to go under the boat rathe than riding them and on way back lots of use of throttle control and going across biggest waves, it was very fun.

This has always intrigued me somewhat. If I were to end up being out in really rough conditions where the water was breaking over the bow or sides to flood the boat, the last thing I'd be wanting to do is let go of the wheel to let the trunks down. How in reality do people operate their trunks? Do you leave them trailing free whenever conditons are rough, or deploy only if needed? I've also wondered about having the bit of cord swilling around in the water near the prop.

[captnjack]

Pics of the new trunk. Works brilliantly
http://www.rib.net/forum/members/4333-albums201.html

[9D280]

Originally Posted by Erin

This has always intrigued me somewhat. If I were to end up being out in really rough conditions where the water was breaking over the bow or sides to flood the boat, the last thing I'd be wanting to do is let go of the wheel to let the trunks down. How in reality do people operate their trunks? Do you leave them trailing free whenever conditons are rough, or deploy only if needed? I've also wondered about having the bit of cord swilling around in the water near the prop.

I replaced the silly short bit of string with a length of rope that runs all the way to the helm position along the toobs. (I have the advantage of 5 grab handles along the toobs through which I can thread it - some of these stick - on eyes could do the same job).

The rope (4mm multistrand) is tied just ahead of where I sit with a slack looped bowline. I then have a small stainless hook tied to the rope at a position which hooks the hook onto the loop formed by the bowline when the trunk is up. to deploy, I simply unhook. To retrieve, I pull the hook & hook it on. Don't even need to stand up!

I found I had to splice a bit of bungee on to the rope & tie it back to the transom to overcome the friction & pull the cord out to drop the trunks when unhooked. Worth installing anyway as it also keeps the rope in tension when the trunks are up and keeps the hook in place.

When down there is not enough slack for the rope to go anywhere near the prop.


Before I rigged that I used to just deploy & ignore if it looked like it was going to be wet.

[Dr Doof]

I just put mine down before I head out. It's fine when your under way.