Bavaria 30 Cruiser keel offset

[catlotion]

Hi everyone,

Does anyone know the keel offset for a tandem keel Bavaria 30 cruiser please?  (Standard Raymarine transducer)

Thanks

Toby

[PEA-JAY]

Keel offset is the measurement from the face of the transducer to the ground if your boat is resting on its keel/keels, so what your instrument displays is clear water beneath the keel. For the purpose of calibrating your Raymarine depth sounder you’re probably looking at a value of between 1.0 to 1.5 metre. I would rather over than understate the value.
Regards,
Raph.

[Salty]

I’d suggest if you are worried about how much offset to apply to your echo sounder reading to allow for the depth of the keel below the hull, then make a decent estimate of its depth and add on whatever you think would be a reasonable safety margin for those situations when you might be near enough to touch the sea bed. Then next time you get lifted out measure and correct your original setting, but still add on a bit for safety, and always slow down when in shallow water so that if you do run into something you do it very gently. The last thing you need is to damage the keel mounting arrangement.

[Yngmar]

I find it best to calibrate in the water. Either stand under the keel or use a lead line if the water is too cold/deep for that Make sure you're on a level bottom with no growth for accuracy.

[catlotion]

I’d suggest if you are worried about how much offset to apply to your echo sounder reading to allow for the depth of the keel below the hull, then make a decent estimate of its depth and add on whatever you think would be a reasonable safety margin for those situations when you might be near enough to touch the sea bed. Then next time you get lifted out measure and correct your original setting, but still add on a bit for safety, and always slow down when in shallow water so that if you do run into something you do it very gently. The last thing you need is to damage the keel mounting arrangement.

sorry - I should have clarified. I'm sailing on Windermere and the depth is marginal on a lot of jetties (but not that serious).  It's always a slow process coming into these places but would be good to have an accurate offset to see where you can sneak into without bumping the bottom.  Although I realise accuracy at this level is probably pretty poor.

[Symphony]

My 33 has a shoal draft keel giving a draft to waterline on 1.5m. I measured the keel recently and it is exactly 1m from the hull to the bottom. The transducer I estimate is probably 10cm higher than the junction of the keel to the hull. I think your total draft is a bit less at 1.4m so the distance from the transducer to the bottom of the keel will be 1m.

Like you I spend quite a lot of time in shallow water (in Poole Harbour and parts of the Solent) but my personal preference is to set the echo sounder from the waterline, with an offset of .4m.

[catlotion]

That's great. Just what I was after. Thanks!