1802.] 
boats were firtt built, will account for my 
having, paid fome attention to them.— 
W ouldhave’s model was fhewn to me fome. 
time fince ; and having particularly noticed 
fome of the boats built by Mr.Greathead, 
I am firmly of opinion, that, notwith- 
ftanding fome difference in the form and 
materials, the life-boats are conftructed 
after Wouldhave’s model, and that every 
cafe in which it has been departed from, 
has, inftead of adding any real excellence, 
been the means of rendering the veffel lefs 
adapted to the purpofe for which it was 
conftru&ted. Thefe will certainly be called 
bold (perhaps impudent) affertions, but I 
truft I fhall be able to convince the unpre- 
judiced that there has been {ome very un- 
fair play in this bufinefs. 
1. Let the capacity of Mr. Greathead’s 
boats for motion be confidered on the re- 
ceived principles of thip building. —Every 
marine architect will allow, that the op- 
pofing of a concave body to the fluid 
through which it has to pafs, is an impro- 
priety, as it muft caufe too great a quan- 
tity of eddy water, and hinder the fluid 
particles from falling on the after body 
with that impetus neceffary to make the 
veffel pafS with the greateft velocity 
through the fluid. 
Two of the life-boats which I have 
{een have concave water-lines at the ends ; 
confequently, however little the concavity 
may be, it is a defect or impropriety in 
the conftru@tion. Ina completely-formed 
veffel, all fudden turns in the timbers, as 
well as unfairnels of the water-lines fhould 
be avoided ; and if it is allowed that a 
bedy-fection fhould exhibit a fair {weep, I 
am certain the life-boats have no claim to 
excellence in their form, fince from the 
keel to the bilge they are very flat, where 
they take a turn almoit as fudden as that 
in a Dutch {chuit. 
A very flight acquaintance with the 
laws of impuifion, refiftance, &c. in the 
divifion of fluids, will enable us to deter- 
mine upon the propriety of having the di- 
viding part of the body as regular as pof- 
fible, and of a form calculated to make 
the leaft poffible refiftance. Tonly remark 
on the nature of fluids, that their mobi- 
lity is eafy, or the contrary, as the confti- 
tuent particles, by their form, are calcu- 
lated for flipping paft each other, and that 
every buoyant body moving in them muft 
difplace a quantity equal to its weight.— 
Now, from this many will be induced to 
fuppofe, that the fmaller the furface of the 
dividing part of the body, the more eafily 
will the divifion be effected ; and in a li- 
mited fenfe this is certainly true; but, it 
does not thence follow, that a cuneiform 
MontTHiy Mac. No, 93. 
Invention of Life-boats. 
319 
body, with the point oppofed to the flu- 
id, will move with fwiftnefs, (or indeed 
at all) in that direétion ; and the reafon 
why a fine entrance does not enfure a 
quick motion is, that every point of the 
furface, from the entrance to the main- 
breadth, muft operate upon the fluid. to 
effet fuch a divifion of it as is neceflary 
for the paflage of the moving body. Now 
the particles impinging on the moving 
body, will be repelled in a direétion equal 
to half the angle of incidence ; thele par~ 
ticles being again impinged upon by the 
fucceeding ones, will not be able to cicape 
in right lines, but will be carried towards 
the after-body ina kind of f{piral curve ; 
and the more regular the convexity of the 
body, the greater will be the impetus 
with which they will rufh into the vacu- 
ity made by its progreffion throvgh the 
fluid. 
In this refpeé&t, Wouldhave’s model is 
much fuperior to the boats built by Mr. 
Greathead, as there is not the moft diflant 
approximation to a hollow in any part of 
its outfide ; confeyuently his mocel is as 
completely fitted for a rapid movement, as. 
a veffel intended to row with either end op- 
pofed to the fluid can be, it being evident 
that the globous particles mult. efcape 
along a convex furface more eafily than 
along any other. 
2. With refpeé to ftrength, it appears: 
to me, that there is a greater probability 
of a boat built of timbers and plank go- 
‘ing to pieces alongfide of a fhip in a heavy 
fea, than there is of one confruéted atter 
the manner propofed by Wouldhave ; for 
that plank may be broken more eafily than 
fheet-copper is undeniable. I therefcre 
may be allowed to fay, that in this refpect 
Mc. Greathead’s boats, at leaf, are not - 
fuperior to the plan of Wouldhave’s. 
3- With regard to the curvature of the 
keel, the only thing which Mr. Greathead 
can claim in the conftru€tion, I feel no he 
fitation to affert, that it is not his inven- 
tion; and Iam not a little furprifed to 
obferve the encomiums. lavifhed upon it 
by fome who fhould have known better. 
The boats uled in the whele fifhery. 
have curved keels, (very little) not to 
make them good fea-boats, but for the 
convenience of launching them more eafily 
among the ice; the fifhers being often un- 
der the neceflity of hauling them a confi- 
derable way upon it, as may he eafily gon- 
ceived from the nature of that country. 
There is a boat.ufed. in the Weft Indies, 
called a mofes, to bring the produce, from 
fhores where there is.a conilant and heavy 
furf: this veflel has a,curyed keel, not to 
render it more fit to keep the fea, but to 
Ss facilitate 
