Check your Humber elephant tube!

HUMBER P4VWL · 30 November 2011, 19:51

Our rib has sat on the mooring since new (ex demo). Ever since we had it, after a few days or so it would have water in its anchor locker and inner hull. We assumed it was water coming in through the anchor hatch and water seeping past the bung from the rear well. Ian Sharlot who aftermarket fitted it out and Humber advised this may be right and told us to remove the bungs so it flowed thorugh the inner hull, to the rear well where we have a bilge pump. All has been fine, but we always thought there was too much water, especially if it hadnt rained much. However we thought it could be the U bolt on the bow.

The u bolt on the bow, entering the anchor locker, was slightly loose after each season and we thought that might have let the water in over time as the waves rose up and down.

Anyways, we got her home today and put the bung in the anchor locker and filled it with water, a dribble came out through the U bolt, but not enough.

Next thought was more worrying, a delaminated hull, or a crack, as it was a demo boat, not entirely new, your mind runs away with itself. So we filled the inner hull with water with rear bung in and watched..... nothing. Hmmm, at least our worries re the hull were ill founded.

The old man then decided to fill the whole boat........ Jesus! It was pissing out of the lower part of the elephant trunk plate on the back of the boat. On further inspection, we also noticed the bottom lip of the circular plate attached to the hull extended about half an inch past the flush lower hull line. At speed, obviously the water flow puts pressure on this and will have undoubtedly loosened the plate. At rest on the mooring, the plate is under the water line, so water has dribbled slowly in, drains to the rear well and once full seeps past the rubbish rubber bung in the rear of the inner well.

Ah well, problem solved, we're shaving the plate where it extends past the hull line to make it flush, re gasketing the plate and screwing in tightly. We will then put a brass screw in the rear drain of the inner hull to the rear well.

Thought I'd share our experience so people can check theirs. No idea if fitted by Ian or Humber to be fair.

9D280 · 01 December 2011, 13:41

Am I reading this right that you have a "top hat" screwed to the transom with the flange poking down below the bottom of the hull?

For what its worth, mine consists of a short length of plastic pipe that is resin / sikaflexed into a hole not much bigger than it is. The trunk is then gooped onto the protrudng pipe. No flanges / gaskets.

The inside diameter of the hole is glassed so it is absolutley watertight & the transom won't rot when the glue gives up.

alystra · 01 December 2011, 14:24

Mine seems to be a piece of pipe through the transom, no flange. No obvious problems as yet, though the trunk itself is a little short - only an inch or so above the waterline and prone to scooping up a bit of water when stopped in any waves.

I have the same problem with the anchor locker collecting rain water and despite a couple of attempts haven't made the hatch waterproof yet. However, the bungs at each end of the inner hull do keep the water out. Never found more than a cupful in there at the end of each season.

Ah 9D280, beat me to it.

captnjack · 01 December 2011, 18:29

Can you guys post some pictures?
I just built a trunk on my boat (and will post some pics soon). I'm not imagining the issues completely
Thanks!

9D280 · 02 December 2011, 09:37

Quote:

Originally Posted by alystra

though the trunk itself is a little short - only an inch or so above the waterline and prone to scooping up a bit of water when stopped in any waves.

Ironically I have the opposite problem - Having already cut about 2" off the end they still catch the wake wave coming back to centre off the toob and are pushed back up the face of it so it forms a U bend & never completely drains! Removing another 3-4" is on my long list of jobs & tweaks....

My theory is when up, matching the height of the engine cutout is high enough. If the wave is big enough to get over there the trunks are going to make no difference to the deck puddle!

alystra · 02 December 2011, 12:11

Quote:

Originally Posted by 9D280

Ironically I have the opposite problem - Having already cut about 2" off the end they still catch the wake wave coming back to centre off the toob and are pushed back up the face of it so it forms a U bend & never completely drains! Removing another 3-4" is on my long list of jobs & tweaks....

My theory is when up, matching the height of the engine cutout is high enough. If the wave is big enough to get over there the trunks are going to make no difference to the deck puddle!

Ah. Never thought of that. Mine's a bit lower than the engine cut out. Actually, I rarely use the thing, relying for the most part on the two bilge pumps in the well, one the standard switched one and the other with a float switch for use on the mooring. I suppose if I sorted out the string so I could reach it from the helm I might use the trunk more, but I'm sure to forget it and end up paddling as soon as I stop moving.

9D280 · 04 December 2011, 00:49

Quote:

Originally Posted by alystra

Ah. Never thought of that. Mine's a bit lower than the engine cut out. Actually, I rarely use the thing, relying for the most part on the two bilge pumps in the well, one the standard switched one and the other with a float switch for use on the mooring. I suppose if I sorted out the string so I could reach it from the helm I might use the trunk more, but I'm sure to forget it and end up paddling as soon as I stop moving.

Aye, having them workable from your seat is useful. Mine are. (apilogies if this goes randdom, I'm a bit laphroig'ed tonght). TBH I've never found they ingest a lot even if I forget to pull them up. The trunks float, and the open end is not entirely underwater so as ong as you half remember it's arrite. Wellies usually solve the smallamount of water problem!

HUMBER P4VWL · 04 December 2011, 09:08

I agree, ours are up to the engine cut out. When at rest, the tube floats up as the water line rises, it then doesn't really let any in. Rear well with bilge is the best for dry decks. Ours has float for mooring use, but it works while used to. The old SR didn't have a well and it was always wet.

Only put trunk down when in rough weather and there's risk of a wave coming over.