Dick Lemke started the thread Is this really a better idea? in The Local Pub with an image of a concept 90’ IACC yacht (#1 below). The bow got me thinking how in a decade, the pointy end of my boats have gone from traditional to plumb. Is there an advantage to sweeping it backward?
I have seen some designs where the bow is somewhat of a compound, where it is narrowest at the middle (ish) and reverse below and “normal” above, which I guess would promote a straight path through waves rather than the up and down ath. As for a complete reverse bow I guess it could offer the same benefit and while it won’t offe rthe same seagoing ability. The deeper the wave, more bouyancy the bow offers so it may make it easier for the bow to rise through the wave than with a conventional bow. Thats my rambling for the night.
Bow design may offer different subtle effects on the performance of the boat. While the apparant choice would be to slice through the water with the minimal resistance or displacement of water, this type of bow gives up buoyancy and is more prone to diving under the water when sailing downwind. Never losing sight of the fact that models sail in scale conditions unimaginable for full sized boats, smaller models with shorter waterlines may design a bow which doesn’t appear to be the sharpest entry in an attempt to counter this very problem. There are also attempts in this area to provide for dynamic lifting or anti-diving in the form of a more blunt or ramp like bow to either prevent the bow from going under, or help it recover more quickly if it does.
Current thinking in the development “A” catamaran class.
It’s all about wave “Piercing” - not wave “Bouncing”. Remove the “hobby-horse” effect and retain laminar flow on the entire sail. If mast tip is swinging many degrees forward, then aft as boat goes “over” waves - if you can remove that action (or lessen) so much the better.
I was a little surprised that this topic didin’t get more replies, especially from those who choose to apply themselves to the technical side of the hobby. A reverse bow seems like either a great idea revisited or a folly while looking for minimal seaway.
You’ll see it in my next yacht build… Is anyone using this design option in their model sailboat construction?
I have never seen a reverse bow applied, I would think because it’s counter productive to the formula of any class I am familiar with. You are measured on waterline or LOA… in the waterline group…it would definitely be a bad idea because you are giving up speed. In the LOA group… you could do it without giving up any length/speed… but you would decrease the ability to prevent the bow diving going downwind.
I am trying such an bow on my new RG 65. I hope to minimise the bowmovement when sailing upwind. The only problem i expect could be the danger of nouse diving when sailing downwind in strong winds.
Hi Larry _Ludwig, As I originally posted… “Are there applications for RC yachts (in the Open Class, “not thinking of rules” category)?” And you say, “… I can’t see any reason to use it.” Gotta keep an open mind (see below).
SvenK… saw your CAD images on the other forum by way of haegar’s link… when the time comes that you have pictures of your boat, it sure be nice to see the “pointy” end of it.
I appreciate the continued dialogue here, from all.
Hi Larry _Ludwig, Just to keep this in the theory realm, I originally posted… “Are there applications for RC yachts (in the Open Class, “not thinking of rules” category)?” So I’m thinking your comment, “… I can’t see any reason to use it.”, means as rules apply. But SvenK has to deal with rules and he feels it has merit.
SvenK… saw your CAD images on the other forum by way of haegar’s link… when the time comes that you have pictures of your boat, it sure would be nice to see the “pointy” end of it.
I appreciate the continued dialogue here, from all.
Me … my F-48/Mini40 multihull class. Since photo taken, I have angled the vertical bow back slightly. Since I have yet to glass it, I may go a bit more extreme.
The photos are more representative of the Phillips multihull of a few years ago.
Have you considered anti-diving planes at the bows. Looking at the rules more closely, I notice that hull projections are only prohibited below the water line. Putting a wing on the rudder would have a similar effect but would mean fitting the rudder more forward to avoid the wing extending beyond the transom at full rudder movement.
yes i thought about such things. But i will try to solve the problem without foils (because of the added resistance). I will try a low Rig (minimise the moment) and put my akku a small wagon to pull it aft when sailing downwind. If this is not enougth i will try foils.
it has nothing to do with whether it would work on a model, just proof that it has been used under a rule, where millions have been put into design, so there is a reason for it.
interesting. i never have give much thought to it. but it could be a way to get your waterline. and lower your wieght. say you are making an IOM. you could have you water line be 1000 mm. but your deck could pull back to 900
this may have some possiblities. still think is would drag the boat under. but maybe look at a 3 rater. that boat is not a box rule. what do you say dan. do you think this would work in a 3r?
cougar:zbeer:
