what should i expect?

[markymarkP]

hi chaps,

i have just got the new rib, and want to take her out for a try dive on saturday.
i understand these things are a bit of trial and error, but wondered if i post up the specs, if anyone can give me an idea of what i should be able to expect:

she is
Bombard 6.2 mtr (SB620)
max weight 1600kg
unlaiden weight 400kg
115hp mercury 2stroke 20" prop
plated to take 12+skipper

so how many divers will she take, including all the kit etc, and what speed should she achieve when laden?

any help appreciated!

will know for sure on saturday!

[SeaSkills]

As you say, it's a bit trial-and-error. There is going to be a trade-off between load and performance, and my guess is that you're not going to carry many divers plus kit in a boat that size/weight with that size engine.

If you're not going far and you want to take a bigger group and don't mind taking longer getting to your dive site ... well, try it with 8 and see what happens

On the other hand, if your dive site is a little further away and you want to get there and back comfortably on the plane ... I'd be inclined to give it a go with maybe 4 to start with and see how you get on. With full kit you may need to get weight forward and full power to get onto the plane.

Bottom line is - I think you'll find you might be happier with a bigger engine to do the job you want (I'd be very pleased for you if I'm proved wrong)

Best of luck

Ian

[markymarkP]

Hmmm... i was going to try with 6 divers plus skipper on saturday, and see what happens!

[willk]

Try the six divers and their Paraphenalia. Put the load forward (along with the spare fuel ). I think you'll get somewhere in the mid-low 20s (kts)

[Polwart]

Originally Posted by willk

Try the six divers and their Paraphenalia. Put the load forward (along with the spare fuel ). I think you'll get somewhere in the mid-low 20s (kts)

In which case is a 20" prop not massively oversized? I'd have thought something closer to 13-15" for those speeds ? And if I'm right then he may struggle to get on the plane when laden. Of course a 13" prop will rev the tits off the motor when unladen, so will need judicious use of the throttle or swapping props for the load on the day.

[markymarkP]

thanks guys, font of knowledge as always,

i will report back after saturday, and see what i get

will do as suggested


best

[Cookee]

Originally Posted by markymarkP

Bombard 6.2 mtr (SB620)

plated to take 12+skipper

They must have plated that on a particularly optimistic day!

[markymarkP]

here are the specs from them direct:

http://www.boat-finder.com/12518/details.php

[Polwart]

Originally Posted by Cookee

They must have plated that on a particularly optimistic day!

It doesn't mean its designed to take 12 - just it won't sink if you do (and makes no promises about getting on the plane). Not quite as bad as Zodiac who put it in the product name...

[markymarkP]

well, i did wonder where they would all sit! even on the tubes, it seemed a lot!

i think my idea of about 6 is better. it has seats for 7.

suck it and see. i am not wanting to take loads, just interested in the possibilities