starboard dive

[gonfishing]

i went out on a mates boat today a pilot 17 just to blow out the cobwebs had an unerving experiece, i am familiar with the cathedral hull and small planing boats, so was putting this thing through it's paces, when on a relatively flat sea at 15knts the boat took a serious dive to starboard nearly got thrown out of boat!!! so we stopped checked engine leg for rope /nets /general fouling nothing, so carried on our way boat came up on plane at about 10/12 knts at about 15/16 knts same again hard dive to starboard,!!!!!!now i keep all decks clear ,only the required equipment for journey envisaged stowed and secured thers was no free flow of water in the bilges , no shifting of heavy weights, and the little thrust tab on the sacrificial anode on the leg was still offset by about 10 degrees same as last year, we went shoreside pretty quick and could find nothing wrong has anyone any ideas???? please !!!! i just got to go fishing !!!!

julian

p.s engine is a 55 johnson

<hr width=100% size=1>Summer is going to pass before i find a boat!!

 

[DavidJ]

Is the engine set too high or at the wrong angle. I know the situation is very different but I had a 19 footer with a stern drive but if the trim tabs were set too low then at speed a slight turn of the wheel would send the boat diving to one side alarmingly.
David

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[byron]

<font color=blue>I think I know the answer but hesitate to put it here in case I am off on the wrong track. Can I suggest you pose the question on <A target="_blank" HREF=http://www.oceaneagle.fsnet.co.uk>http://www.oceaneagle.fsnet.co.uk

<A target="_blank" HREF=http://www.alexander-advertising.co.uk>http://www.alexander-advertising.co.uk</A>

 

[DavidJ]

Just had a look at Boatmadforum (Byron junior member??) I notice that their photo space dimensions are far more pleasing than ybw and more suited to the proportions of boats. Any interest out there to get the dimensions changed for us (will this cause B1 problems since he hosts most of the pics)
David

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[jfm]

baffling......

Most odd. I know this hull well - the mould has been cloned by many builders and I have had the open (non-cuddy) version with double skin foam filled construction - an excellent boat. I had one built with reinforced transom and ran it with 125hp (which is way more than manufacturers say - I think they sed 85hp maximum). IIt did 45knots on the GPS.

Never had any problems that you describe, I'm completely baffled. It is hard to think it could be weight moving around, you would need a lot of weight to get that much heel. In fact, I find it very insensitive to weight distribution.

On a high power-to-size set up I mount the outboard about 1.25 inches to starboard of the centre line (assuming a R/H prop), mostly to balance the steering pull, but even if you didn't do that it would not induce the heel you describe.

Your problem must be caused by a hydrodynamic effect. It can't be the prop becuase on the Johnson it's a right hander (I'm pretty sure) so the boat would tend to spin anticlockwise viewed looking forwards from the transom, and yours is going clockwise. Anyways, the turning effect will only be slight with a 55hp.

Did it do this when going straight or were you doing tight turns and digging the outer keel in?

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[ArthurWood]

Is there one of those Doel Fin thingies fitted to the anti-cav plate? I had the same thing happen when I fitted one (not Doel) to a 165hp on a 19ft boat. Very disconcerting!

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